| Pneumococcal Resistance Most S. pneumoniae strains gain penicillin resistance by altering the penicillin-binding proteins in their cell wall. Penicillin molecules that cannot find a penicillin binding site cannot interfere with cell wall synthesis. Several different types of penicillin binding proteins may be involved, explaining the various levels of intermediate resistance that may be encountered with different strains of S. pneumoniae. Because different penicillin binding proteins may be involved, the level of penicillin resistance cannot be predicted by the oxacillin screening test. Infections caused by isolates of S. pneumoniae showing penicillin resistance in the intermediate range may be successfully treated by administering high doses of antibiotic. For this reason, the level of resistance with an accurate minimum inhibitory concentration (MIC) test must be determined for all clinically significant isolates of S. pneumoniae. | View Page |
| Middle ear damage in cases of S. pneumoniae infections are caused primarily by the: (Choose all that apply) | View Page |
| Review 1 Podschun R. Ullmann U.: Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors Clinical Microbiology Reviews. 11(4):589-603, 1998 Bacteria belonging to the genus Klebsiella frequently cause human nosocomial infections. In particular, the medically most important Klebsiella species, Klebsiella pneumoniae, accounts for a significant proportion of hospital-acquired urinary tract infections, pneumonia, septicemias, and soft tissue infections. The principal pathogenic reservoirs for transmission of Klebsiella are the gastrointestinal tract and the hands of hospital personnel. Because of their ability to spread rapidly in the hospital environment, these bacteria tend to cause nosocomial outbreaks. Hospital outbreaks of multidrug-resistant Klebsiella species, especially those in neonatal wards, are often caused by new types of strains, the so-called extended-spectrum-beta-lactamase (ESBL) producers The incidence of ESBL-producing strains among clinical Klebsiella isolates has been steadily increasing over the past years. The resulting limitations on the therapeutic options demand new measures for the management of Klebsiella hospital infections. While the different typing methods are useful epidemiological tools for infection control, recent findings about Klebsiella virulence factors have provided new insights into the pathogenic strategies of these bacteria. Klebsiella pathogenicity factors such as capsules or lipopolysaccharides are presently considered to be promising candidates for vaccination efforts that may serve as immunological infection control measures. | View Page |
| Clinical History A 72- year old woman had a history of recurrent urinary tract infections over the past several months, for which she had received different regimens of antibiotics including ampicillin, trimethoprim-sulfasoxazole, and ciprofloxacin.Relapses often occurred 10 days to two weeks after cessation of therapy.The current flare up, manifest by dysuria, lower abdominal pain and cloudy urine was accompanied by shaking chills and spiking fever.A sterile mid-stream urine specimen was sent to the laboratory for culture.
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| Vancomycin Resistance Vancomycin and ampicillin resistance among Enterococcus species, particularly E. faecium have been on a steady increase. The disk diffusion screening test is used in many laboratories to detect vancomycin resistant strains. Note in the upper image that no zone of inhibition is seen around either the vancomycin or the ampicillin disk, indicating resistance to both drugs. Vancomycin-resistant Enterococci (VRE) have been divided into three phenotypes--Van A, Van B, and Van C. Vancomycin-resistant strains of E. faecalis and E. faecium are commonly of the Van A phenotype, demonstrating high level resistance (MIC's higher than 64 ug/mL), as illustrated by total resistance of the test strain in the E test and the VA disk, as illustrated in the lower image. The strain shown in the lower image, however, is ampicillin susceptible at the level of 1 ug/mL (see lower set of yellow arrows), indicating that this drug may be effective in treating the urinary tract infection. | View Page |
| Review 1 Garbutt JM. Littenberg B. Evanoff BA. Sahm D. Mundy LM. Enteric carriage of vancomycin-resistant Enterococcus faecium in patients tested for Clostridium difficile. Infection Control & Hospital Epidemiology. 20(10):664-70, 1999 OBJECTIVE: To identify independent risk factors for enteric carriage of vancomycin-resistant Enterococcus faecium (VREF) in hospitalized patients tested for Clostridium difficile toxin. PATIENTS: Convenience sample of 215 adult inpatients who had stool tested for C. difficile between January 29 and February 25, 1996. RESULTS: 41 (19%) of 215 patients had enteric carriage of VREF. Five independent risk factors for enteric VREF were identified: (1) history of prior C. difficile infection, (2) parenteral treatment with vancomycin for > or = 5 days, (3) treatment with antimicrobials effective against gram-negative organisms, (4) admission from another institution, and (5) age > 60 years. These risk factors for enteric VREF were independent of the patient's current C. difficile status. CONCLUSIONS: Antimicrobial exposures are the most important modifiable independent risk factors for enteric carriage of VREF in hospitalized patients tested for C. difficile. | View Page |
| What is the most important modifiable risk factor for enteric colonization with vancomycin-resistant Enterococcus faecium (VREF)? | View Page |
| Gas gangrene may be seen in infections with all the following clostridia EXCEPT: | View Page |
| The Gram stain shown in the image was prepared from a positive anaerobic blood culture bottle after 36 hours incubation. Based on the morphology of the bacterial cells (some with spores, noted by the blue arrows), what the most likely identification? | View Page |
| Review 1 Lorimer JW. Eidus LB.: Invasive Clostridium septicum infection in association with colorectal carcinoma. Canadian Journal of Surgery. 37:245-9, 1994 The association between invasive Clostridium septicum infection and colorectal carcinoma is examined by the presentation of three cases and a review of the literature. In the first two cases the patients presented with nontraumatic metastatic clostridial gas gangrene. In the third case a patient with chemotherapy-induced myelosuppression from concomitant multiple myeloma had a necrotizing transmural infection of the right colon. The apparent portal of entry of Clostridium septicum was an occult carcinoma of the ascending colon. The increasing evidence for a strong link between this organism and some cases of neutropenic enterocolitis is reviewed. | View Page |
| Review 2 Citron DM. Appelbaum PC.: How far should a clinical laboratory go in identifying anaerobic isolates, and who should pay? Clinical Infectious Diseases. 16 Suppl 4:S435-8, 1993 Identification of anaerobic bacteria in specimens from sites of infection due to mixed organisms can be time-consuming and expensive. Laboratories should limit anaerobic workups by testing only those specimens that have been properly collected and transported to the laboratory. Use of selective and differential media for initial processing can provide rapid and relevant information to the clinician. Anaerobes isolated from normally sterile sites and sites of serious infection should always be completely identified. Group-or genus-level identifications may suffice in other instances. The Bacteroides fragilis group of organisms should always be identified because of their virulence and resistance to many antimicrobial agents. Some of the other organisms that warrant identification include Clostridium septicum (associated with gastrointestinal malignancy); Clostridium ramosum, Clostridium innocuum, and Clostridium clostridioforme (which are resistant to antibiotics); Clostridium perfringens (a cause of myonecrosis and gas gangrene,potentially serious infection); anaerobic cocci (which may be resistant to metronidazole and clindamycin); and fusobacteria (which may be virulent and resistant to clindamycin and penicillin). | View Page |
| Review 3 Kornbluth AA. Danzig JB. Bernstein LH.: Clostridium septicum infection and associated malignancy. Report of 2 cases and review of the literature. Medicine. 68(1):30-7, 1989 We report 2 patients with myonecrosis due to Clostridium septicum and associated colon carcinoma and have reviewed the English language literature for all reported cases of atraumatic C. septicum infection. A total of 162 cases of C. septicum infection have been reported. Eighty-one percent of these patients had an associated malignancy. Thirty-four percent of all patients had associated colon carcinoma, while 40% had a hematologic malignancy. Thirty-seven percent of reported patients had an occult malignancy at the time of their infection with C. septicum. In many patients, the portal of entry was found in the large intestine. In a particularly lethal form (79% mortality) of C. septicum infection, known as "distant myonecrosis," infection metastatic from the initial site of infection causes severe myonecrosis, gangrene, and often death within hours of clinical detection. Overall, survival of patients with C. septicum infection is only 35%. Review of all cases of C. septicum infection suggests several conclusions. 1) Patients with malignancy, particularly colonic or hematologic, and patients with cyclic neutropenia who develop signs and symptoms of sepsis, especially with associated findings of abdominal pain or pain in an extremity, should be treated for possible clostridial infection. 2) C. septicum infection does not appear to be a result of a single specific defect in either humoral or cell-mediated immunity. Rather, it may occur in patients who are granulocytopenic and therefore prone to an enterocolitis. 3) Patients in whom an infection with C. septicum is found must undergo a vigorous search for malignancy. | View Page |
| Match the species of anaerobes and frequently associated conditions. | View Page |
| Each of the following statements is true concerning Clostridium septicum infections EXCEPT: | View Page |
| A Gram stain of the serous exudate is shown in the image. The appropriate report would read: | View Page |
| Review 1 Francois P. Vaudaux P. Foster TJ. Lew DP.: Host-bacteria interactions in foreign body infections. Infection Control & Hospital Epidemiology. 17:514-20, 1996 Persistent staphylococcal infections are a major medical problem, especially when they occur on implanted materials or intravascular catheters. This review describes some of the recently discovered molecular mechanisms of Staphylococcus aureus attachment to host proteins coating biomedical implants. These interactions involve specific surface proteins, called bacterial adhesins, that recognize specific domains of host proteins deposited on indwelling devices, such as fibronectin, fibrinogen, or fibrin. Elucidation of molecular mechanisms of S. aureus adhesion to the different host proteins may lead to the development of specific inhibitors blocking attachment of S. aureus, which may decrease the risk of bacterial colonization of indwelling devices. | View Page |
| Review 2 Hershow RC. Khayr WF. Smith NL.: A comparison of clinical virulence of nosocomially acquired methicillin-resistant and methicillin-sensitive Staphylococcus aureus infections in a university hospital (University of Illinois at Chicago). Infection Control & Hospital Epidemiology. 13(10):587-93, 1992 OBJECTIVES: To compare the clinical virulence of nosocomially acquired methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) infections in 1989. DESIGN: A retrospective comparison of host factors, in-hospital exposures, sites of infections, and outcomes of patients with nosocomial MRSA and MSSA infections. PARTICIPANTS: Forty-four adult patients with nosocomial S.aureus infections. RESULTS: The 22 MRSA-infected and 22 MSSA-infected persons were similar regarding mean age, gender, underlying diseases, and exposure to surgery. Before developing infection, MRSA-infected persons were more likely to have received antibiotics and to have stayed in the hospital > 2 weeks. Bacteremia was the most common presentation in the MRSA and MSSA groups (55% and 59%, respectively). Infectious complications and death were infrequent in both groups. CONCLUSIONS: MRSA and MSSA strains infect patients with similar demographic features and underlying diseases, but MRSA infections are significantly more common among patients with previous antibiotic therapy and a prolonged preinfection hospital stay. Clinical presentations and outcomes did not differ significantly between the 2 groups. Thus, similar to studies in the early 1980s, our findings do not suggest greater intrinsic virulence of MRSA. | View Page |
| Factors predisposing to infections with methicillin resistant Staphylococcus aureus (MRSA) include: (choose all that apply) | View Page |
| Decreasing the risk of staphylococcal colonization of indwelling catheters in the future may involve: | View Page |
| Patients with infections with MRSA have uniformly poorer outcomes than those infected with sensitive strains. | View Page |
| Most infections caused by S. anginosus can be effectively treated with penicillin or a first generation cephalosporin. | View Page |
| A clinical condition often associated with Streptococcus anginosus ("milleri") is: | View Page |
| Review 1 Piscitelli SC., Shwed J., Schreckenberger P., Danziger LH. Streptococcus milleri group: renewed interest in an elusive pathogen. European Journal of Clinical Microbiology & Infectious Diseases.11:491-8, 1992 The following review examines the bacteriological characteristics, epidemiology, pathogenicity and antimicrobial susceptibility of the "Streptococcus milleri group". "Streptococcus milleri group" is a term for a large group of streptococci which includes Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. Usually considered commensals, these organisms are often associated with various pyogenic infections including cardiac, intra-abdominal, subcutaneous and central nervous system infections, particularly with the formation of abscesses. Organisms of the "Streptococcus milleri group" are often unrecognized pathogens due to the lack of uniformity in classifications and difficulties in microbiological identification. Penicillin G, cephalosporins, clindamycin and vancomycin all possess activity against these streptococci. Use of agents with poor activity may promote infections with "Streptococcus milleri group" and allow it to exhibit its pathogenicity. An understanding of these organisms may aid in their recognition and proper treatment. | View Page |
| Review 2 Gelfand MS. Bakhtian BJ. Simmons BP.: Spinal sepsis due to Streptococcus milleri (anginosus): two cases and review. Reviews of Infectious Diseases. 13:559-63, 1991 We have recently cared for two patients with spinal sepsis secondary to infection with Streptococcus milleri (anginosus). One patient had a spinal epidural abscess and the other had meningitis as well as a spinal subdural empyema. A review of the English-language literature revealed only two previously reported cases of spinal epidural abscess due to S. milleri (anginosus) and no cases of spinal subdural empyema due to S. milleri (anginosus). We report two cases of spinal sepsis due to S. milleri (anginosus) and discuss pertinent literature. | View Page |
| The epidural and subdural abscesses in the two patients reported by Gelfand, et al, are clinical manifestations uncommon for S. anginosus ("milleri"). | View Page |
| Review 1 Spencer RC.: Invasive streptococc European Journal of Clinical Microbiology & Infectious Diseases. 14 Suppl. 1:S26-32, 1995. Before the introduction of antibiotics, serious infections caused by Streptococcus pyogenes (Lancefield Group A streptococci) were common. Before World War II, this bacterium was responsible for as many as 50% of postpartum deaths and was the major cause of death in patients with burns. Also common were the sequelae of streptococcal infections-rheumatic fever and post-streptococcal glomerulonephritis. With the use of penicillin, however, Streptococcus pyogenes was believed to be virtually eliminated as a pathogen. The organism was consigned to the history books, but not for long. In the mid-1980s, focal resurgences of rheumatic fever began to be reported from different areas in the USA, such as Salt Lake City, Utah. In such communities, where increases in cases of rheumatic fever had been reported, the serotypes M-1, 3, 5, 6 and 18 were isolated which, on culture, produced characteristic mucoid colonies. At the same time, reports of increases in invasive streptococcal disease began to surface in both the US and Europe. Two syndromes were described; invasive streptococcal infection, occurring in previously healthy children and adults, commonly associated with septicaemia resulting from a deep focus of infection such as bone or lung; and streptococcal toxic shock syndrome, involving a cutaneous focus, accompanied by necrotizing or bullous soft tissue changes. Septicaemia is rare in streptococcal toxic shock syndrome, but the most characteristic feature is one of rapidly progressing multi-organ failure. A high proportion of the strains of Streptococcus pyogenes associated with this condition are serotype M-1, and fatality rates approaching 50% have been reported. | View Page |
| Review 2 Cunningham MW.: Pathogenesis of group A streptococcal infections. Clinical Microbiology Reviews. 13):470-511, 2000 Group A streptococci are model extracellular gram-positive pathogens responsible for pharyngitis, impetigo, rheumatic fever, and acute glomerulonephritis. A resurgence of invasive streptococcal diseases and rheumatic fever has appeared in outbreaks over the past 10 years, with a predominant M1 serotype as well as others identified with the outbreaks. Emm (M protein) gene sequencing has changed serotyping, and new virulence genes and new virulence regulatory networks have been defined. The emm gene superfamily has expanded to include antiphagocytic molecules and immunoglobulin-binding proteins with common structural features. At least nine superantigens have been characterized, all of which may contribute to toxic streptococcal syndrome. An emerging theme is the dichotomy between skin and throat strains in their epidemiology and genetic makeup. Eleven adhesions have been reported, and surface plasmin-binding proteins have been defined. The strong resistance of the group A streptococcus to phagocytosis is related to factor H and fibrinogen binding by M protein and to disarming complement component C5a by the C5a peptidase. Molecular mimicry appears to play a role in autoimmune mechanisms involved in rheumatic fever, while nephritis strain-associated proteins may lead to immune-mediated acute glomerulonephritis. Vaccine strategies have focused on recombinant M protein and C5a peptidase vaccines, and mucosal vaccine delivery systems are under investigation. | View Page |
| Review 2 Low JC. Donachie W.: A review of Listeria monocytogenes and listeriosis. Veterinary Journal. 153:9-29, 1997 Following the initial isolation and description in 1926, Listeria monocytogenes has been shown to be of world-wide prevalence and is associated with serious disease in a wide variety of animals, including man. Our knowledge of this bacterial pathogen and the various forms of listeriosis that it causes has until recently been extremely limited, but recent advances in taxonomy, isolation methods, bacterial typing, molecular biology and cell biology have extended our knowledge. It is an exquisitely adaptable environmental bacterium capable of existing both as an animal pathogen and plant saprophyte with a powerful array of regulated virulence factors. Most cases of listeriosis arise from the ingestion of contaminated food and in the UK the disease is particularly common in ruminants fed on silage. Although a number of forms of listeriosis are easily recognized, such as encephalitis, abortion and septicaemia, the epidemiological aspects and pathogenesis of infection in ruminants remain poorly understood. The invasion of peripheral nerve cells and rapid entry into the brain is postulated as a unique characteristic of its virulence, but relevant and practical disease models are still required to investigate this phenomenon. | View Page |
| Review 2 Low JC. Donachie W.: A review of Listeria monocytogenes and listeriosis. Veterinary Journal. 153:9-29, 1997 Following the initial isolation and description in 1926, Listeria monocytogenes has been shown to be of world-wide prevalence and is associated with serious disease in a wide variety of animals, including man. Our knowledge of this bacterial pathogen and the various forms of listeriosis that it causes has until recently been extremely limited, but recent advances in taxonomy, isolation methods, bacterial typing, molecular biology and cell biology have extended our knowledge. It is an exquisitely adaptable environmental bacterium capable of existing both as an animal pathogen and plant saprophyte with a powerful array of regulated virulence factors. Most cases of listeriosis arise from the ingestion of contaminated food and in the UK the disease is particularly common in ruminants fed on silage. Although a number of forms of listeriosis are easily recognized, such as encephalitis, abortion and septicaemia, the epidemiological aspects and pathogenesis of infection in ruminants remain poorly understood. The invasion of peripheral nerve cells and rapid entry into the brain is postulated as a unique characteristic of its virulence, but relevant and practical disease models are still required to investigate this phenomenon. | View Page |
| Review 1 Rocourt J. Jacquet C. Reilly A.: Epidemiology of human listeriosis and seafoods. International Journal of Food Microbiology. 62:197-209, 2000 While rarely diagnosed prior to 1960, more than 10,000 cases of listeriosis were recorded in the medical literature between 1960 and 1982, and thousands more have been reported annually world-wide. This widespread increase in reporting is most likely due to demographic trends and changes in food production, processing and storage, especially the extended cold food chain and the ability of Listeria monocytogenes to grow at low temperatures L. monocytogenes is a bacterium responsible for opportunistic infections, preferentially affecting individuals whose immune system is perturbed, including pregnant women, newborns, people over 65 years, immunocompromised patients, such as cancer victims, transplant recipients, people on hemodialysis and AIDS patients. Thus, the increasing lifespan and medical progress allowing immunodeficient individuals to survive, partially explains the increasing incidence of listeriosis. Moreover, L. monocytogenes is ubiquitous and can grow at temperatures as low as 0 degrees C. At this temperature growth is very slow. The expansion of the agro-food industry, the widespread use of systems of cold storage and changes in consumers demands have led to a large increase in the pool of Listeria that can cause food-borne infections. | View Page |
| Review 3 Rouquette C. Berche P. The pathogenesis of infection by Listeria monocytogenes Microbiologia. 12:245-58, 1996 Listeria monocytogenes is a Gram-positive bacterium responsible for severe infections in human and a large variety of animal species. It is a facultative intracellular pathogen which invades macrophages and most tissue cells of infected hosts where it can proliferate. The molecular basis of this intracellular parasitism has been to a large extent elucidated. The virulence factors, including internalin, listeriolysin O, phospholipases and a bacterial surface protein, ActA, are encoded by chromosomal genes organized in operons. Following internalisation into host cells, the bacteria escape from the phagosomal compartment and enter the cytoplasm. They then spread from cell to cell by a process involving actin polymerisation. In infected hosts, the bacteria cross the intestinal wall at Peyer's patches to invade the mesenteric lymph nodes and the blood. The main target organ is the liver, where the bacteria multiply inside hepatocytes. Early recruitment of polymorphonuclear cells lead to hepatocyte lysis, and thereby bacterial release This causes prolonged septicaemia, particularly in immunocompromised hosts, thus exposing the placenta and brain to infection. The prognosis of listeriosis depends on the severity of meningoencephalitis, due to the elective location of foci of infection in the brain stem (rhombencephalitis). Despite bactericidal antibiotic therapy, the overall mortality is still high (25 to 30%). | View Page |
| Which of the following result in most Eikenella cellulitis infections? | View Page |
| Review 1 Newfield RS. Vargas I. Huma Z.: Eikenella corrodens infections. Case report in two adolescent females with IDDM. Diabetes Care. 19:1011-3, 1996 OBJECTIVE: To alert physicians caring for patients with diabetes to the microorganism Eikenella corrodens and to discuss the appropriate preventive and therapeutic measures to take against this potentially morbid opportunistic gram-negative bacilli. CASES: We present two cases of extra-oral E. corrodens infections in adolescent females with IDDM. The first patient had diabetes of four years' duration, which was moderately well controlled. Chronic finger biting resulted in a complex felon that evolved gradually and worsened while the patient received cephalexin orally. Delay in seeking further intervention resulted in necrosis of her distal fingertip and nail bed. The second patient had poorly controlled diabetes for five years. She developed an acute thigh abscess at an insulin injection site that resolved after drainage and intravenous antibiotics. CONCLUSIONS: E. corrodens commonly inhabits the human oral cavity and becomes a pathogen mostly when host defenses are impaired, causing abscesses and infections that are at times fatal. Patients with IDDM are compromised hosts and with daily microtrauma to their skin via glucose monitoring and insulin injections, are prone to develop E. corrodens infections that can be introduced through oral secretions by licking or biting their skin. Educational efforts aimed at preventing exposure of traumatized skin to oral secretions can minimize the risk of E. corrodens infections in compromised hosts. Early intravenous administration of antibiotics, bearing in mind E. corrodens resistance to clindamycin, metronidazole, and other antibiotics, coupled with prompt surgical intervention, is essential in successfully managing E. corrodens infections. | View Page |
| Review 3 Robinson LG. Kourtis AP.: Tale of a toothpick: Eikenella corrodens osteomyelitis. Infection. 28(5):332-3, 2000 Tale of a Toothpick is a case of Eikenella corrodens osteomyelitis in a young woman, that resulted from puncture of her foot with a toothpick. The epidemiology, microbiology, common clinical presentations and therapy of E. corrodens are reviewed. A brief summary of the extent of toothpick injuries and their infectious complications are also presented. | View Page |
| To avoid infection with E. corrodens, what are patients with insulin-dependent diabetes mellitis (IDDM) advised NOT to do? (Choose all that apply) | View Page |
| Review 2 Griego RD. Rosen T. Orengo IF. Wolf JE.: Dog, cat, and human bites: a review. Journal of the American Academy of Dermatology. 33:1019-29, 1995 It is estimated that half of all Americans will be bitten by an animal or another human being during their lifetimes. The vast majority of the estimated 2 million annual mammalian bite wounds are minor, and the victims never seek medical attention. Nonetheless, bite wounds account for approximately 1% of all emergency department visits and more than $30 million in annual health care costs. Infection is the most common bite-associated complication; the relative risk is determined by the species of the inflicting animal, bite location, host factors, and local wound care. Most infections caused by mammalian bites are polymicrobial, with mixed aerobic and anaerobic species. The clinical presentation and appropriate treatment of infected bite wounds vary according to the causative organisms. Human bite wounds have long had a bad reputation for severe infection and frequent complication. However, recent data demonstrate that human bites occurring anywhere other than the hand present no more of a risk for infection than any other type of mammalian bite. The increased incidence of serious infections and complications associated with human bites to the hand warrants their consideration and management in three different categories: occlusional/simple, clenched fist injuries, and occlusional bites to the hand. This article reviews dogs, cat, and human bite wounds, risk factors for complications, evaluation components, bacteriology, antimicrobial susceptibility patterns, and recommended treatments. Epidemiology, clinical presentation, and treatment of infections caused by Pasteurella multocida, Capnocytophaga canimorsus, Eikenella corrodens, and rhabdovirus (rabies only) receive particular emphasis. | View Page |
| Human bite wound infections are categorically more severe and more often lead to complications than infected bites from other animals. | View Page |
| Chemical Urinalysis Reagent Strips A chemical urinaylsis reagent strip, also called a dipstick, for screening urine is a narrow band of paper which has been saturated with chemical indicators for specific substances or properties. Depending on the product being used, chemical urinalysis reagent strips may include test indicators for glucose, bilirubin, ketones, specific gravity, blood, pH, protein, urobilinogen, nitrite, and leukocyte esterase. The results obtained from urine screening using chemical urinalysis strips can indicate the patient's carbohydrate metabolism status, kidney and liver function, urinary tract infection, and acid-base balance. Most chemical urinalysis reagent strips can be read visually and do not require instrumentation for automatic reading, though many laboratories utilize instruments for this purpose. When performing chemical urinalysis reagent strip analysis, the directions must be performed exactly. Accurate timing is paramount in order to achieve appropriate and optimal results. In addition, the reagent strips must be stored properly in their containers with the lid tightly closed to maintain reagent reactivity. It is always essential to utilize well-mixed urine which has been collected within 2 hours of analysis.Always read the package insert for your particular brand of chemical urinalysis reagent strip, as each manufacturer may have slightly different instructions and interpretations. | View Page |
| Urine pH: Acidic and Alkaline Urine pH results must be evaluated in conjunction with a patient's medical condition and clinical history. Factors to be considered include:Respiratory and metabolic statusRenal functionCrystal or calculi formationDietThe table below summarizes dietary and medical conditions as well as preanalytic and analytic errors that may affect urine pH:ConditionAcid pHAlkaline pHHigh meat dietXVegetarian dietXRespiratory/metabolic acidosisXRespiratory/metabolic alkalosisXHypochloridemiaXHigh concentration of urine glucoseXBacterial infection caused by urease-producing bacteriaXProlonged storage of specimen at room temperature, allowing multiplication of urease-producing bacteriaX (above 8.0)Improper procedural technique; excess urine left on reagent strip, allowing acid buffer in protein pad to run over into adjacent pH pad (refers to some reagent strip configurations)XKidney failureXUrinary tract infectionsXVomitingXDiabetic ketoacidosis XDiarrheaXStarvationX | View Page |
| Clinical Significance of Glucose in the Urine In a healthy individual, almost all of the glucose filtered by the renal glomerulus is reabsorbed in the proximal convoluted tubule. The amount of glucose reabsorbed by the proximal tubule is determined by the body's need to maintain a sufficient level of glucose in the blood. If the concentration of blood glucose becomes too high (160-180 mg/dL), the tubules no longer reabsorb glucose, allowing it to pass through into the urine. It is important to note that glucose may appear in the urine of healthy individuals after consuming a meal that is high in glucose. Fasting prior to providing a sample for screening eliminates this problem. Conditions in which glucose levels in the urine are above 100 mg/dL and detectable include: diabetes mellitus and other endocrine disordersimpaired tubular reabsorption due to advanced kidney diseasepregnancy - glycosuria developing in the 3rd trimester may be due to latent diabetes mellituscentral nervous system damagepancreatic diseasedisturbances of metabolism such as, burns, infection or fractures | View Page |
| False Positive and Negative Urine Bilirubin Results False Positive BilirubinFalse positive results may occur when patients are on large doses of chloropromazine, and may occur in the presence of metabolites of phenazopyridine. When these compounds are present, the urine becomes red. Metabolites of Lodine® (etodolac) may cause false positive or atypical results. False Negative BilirubinFalse negative bilirubin dipstick results are often due to testing a specimen that is not fresh. Bilirubin breaks down when exposed to light. Indoxyl sulfate (Indican) can produce a yellow orange-to-red color response which may interfere with the interpretation of a positive or negative reaction. Positive nitrites due to a urinary tract infection may also cause a false negative result. | View Page |
| Urine Analysis for Nitrites The nitrites portion of the chemical reagent strip provides a rapid screening test for the presence of gram-negative bacteria that are often responsible for urinary tract infections. Urine cultures are still needed to confirm the diagnosis and monitor any urinary tract or kidney infection. Diagnosis and treatment of cystitis (bladder infection) is important because, if left untreated, it may result in kidney damage, impairment of renal function, hypertension and/or septicemia. | View Page |
| Nitrite Test Sensitivity This test is sensitive to 0.06-0.1 mg/dL nitrite ion in urines with a low specific gravity and with ascorbic acid concentrations of less than 25 mg/dL. Pink spots or pink edges should not be interpreted as a positive result because some medications can color urine red or turn red in an acid environment. Any degree of uniform pink color should be considered positive, suggesting the presence of 105 organisms/mL. Detection of low levels of nitrite ion may be enhanced by comparing the activated test strip to a white background. It is important to note that color development is NOT proportional to the number of bacteria present. The test is specific for nitrites and does not react with any other substances normally present in urine. Negative results do not necessarily rule out a urinary tract infection with yeasts or gram-positive bacteria unable to reduce nitrites. | View Page |
| Clinical Significance of Nitrites in Urine Early detection of bacteria is important in order to prevent cystitis from developing into inflammation or infection involving the kidney and renal pelvis. The nitrite portion of the test strip can be used to screen individuals who are at risk for developing urinary tract infections, such as diabetics, persons with recurrent infections, or pregnant women. The test is also useful in evaluating the success of antibiotic therapy that is used to treat a bladder infection. | View Page |
| The nitrite portion of the test strip can be used to: (Choose ALL correct answers) | View Page |
| Presence of Granulocytes in Urine Granulocytic white blood cells in a urine sample suggest the presence of a urinary tract infection. Granulocytes, which include neutrophils, basophils and eosinophils, contain esterases. These esterases catalyze the urine chemical reagent strip reaction where indoxylcarbonic acid ester releases indoxyl. Indoxyl reacts with a diazonium salt to produce a purple color. The intensity of the color produced is proportional to the amount of enzyme present. | View Page |
| A patient suspected of a urinary tract infection has a negative nitrite test, but bacteria is present upon microscopic examination. What may have caused this discrepant result? (Choose ALL of the correct answers) | View Page |
| Match the following reagent strip tests to the disease or disorder that would most likely cause a positive test result. | View Page |
| A voided urine specimen is delivered from the women's clinic to the laboratory six hours after collection. The following results are reported:Color: yellow Protein: negative Bilirubin: negativeClarity: cloudy Glucose: negative Urobilinogen: 0.2 mg/dLSp. Gravity: 1.020 Ketone: negative Nitrite: positivepH: 9.0 Blood: negative Leukocyte esterase: negativeWhat might these results indicate? | View Page |
| Acid and Alkaline Urine pH Urine pH results must be evaluated in conjunction with a patient's medical condition and clinical history. Factors to be considered include:Respiratory and metabolic statusRenal function Crystal or calculi formationDietThe table below summarizes dietary, medical, and artifactual conditions that may affect urine pH:ConditionAcid pHAlkaline pHHigh meat dietXVegetarian dietXRespiratory/metabolic acidosisXRespiratory/metabolic alkalosisXHypochloridemiaXHigh concentration of urine glucoseXBacterial infection caused by urease-producing bacteriaXProlonged storage of specimen at room temperature, allowing multiplication of urease-producing bacteriaX (above 8.0)Improper procedural technique; excess urine left on reagent strip, allowing acid buffer in protein pad to run over into adjacent pH pad (refers to some reagent strip configurations)X | View Page |
| Clinical Significance cont'd Conditions in which glucose levels in the urine are above 100 mg/dL and detectable include:diabetes mellitus and other endocrine disordersimpaired tubular reabsorption due to advanced kidney diseasepregnancy - glycosuria developing in the 3rd trimester may be due to latent diabetes mellituscentral nervous system damagepancreatic diseasedisturbances of metabolism such as, burns, infection or fractures | View Page |
| False Negative Results False negative bilirubin dipstick results are often due to testing a specimen that is not fresh. Bilirubin breaks down when exposed to light. Indoxyl sulfate (Indican) can produce a yellow orange-to-red color response which may interfere with the interpretation of a positive or negative reaction. Positive nitrites due to a urinary tract infection may also cause a false negative result. | View Page |
| False Positive Results A false positive result for blood on the reagent strip can occur when oxidizing contaminants, such as hypochlorite (bleach), remain in collection bottles after cleaning. Contamination of the urine with provodine-iodine, a strong oxidizing agent, used in surgical procedures can result in a false positive reaction. Microbial peroxide found in association with urinary tract infections may also cause false-positive results. Capoten® (Captopril) can cause decreased reactivity. The muscle tissue form of hemoglobin, myoglobin is a well-known cause of false-positive reactions on the blood portion of the reagent strip. When tissue hemoglobin is present, the urine specimen has a clear red appearance. Patients suffering from muscle-wasting disorders or muscular destruction due to trauma, prolonged coma, or convulsions or individuals engaging in extensive exertion may have myoglobin in their urine. Specific tests for myoglobin, such as immunodiffusion techniques or protein electrophoresis, are needed to confirm the presence of this substance in a urine specimen. Levels of ascorbic acid normally found in urine do not interfere with this test. | View Page |
| Clinical Significance No blood is found in the urine of healthy individuals although samples from menstruating females, frequently, but not always, test positive for blood. Hematuria is associated with renal or genital urinary disorders in which the bleeding is the result of irritation to the involved organs or trauma. Examples include renal calculi, pyelonephritis, glomerulonephritis, tumors, trauma or exposure to toxic chemicals or drugs and/or strenuous exercise. Hemoglobinuria may be due to the lysis of red cells within the urinary tract. If it is caused by intravascular hemolysis, the hemoglobin is then filtered through the glomeruli. In the normal individual, the hemoglobin molecule attaches to haptoglobin and in this way bypasses the kidney filtration system. When the hemoglobin/haptoglobin system is overwhelmed, as in cases of hemolytic anemia, severe burns, transfusion reaction, infection or strenuous exercise, hemoglobin passes into the urine. | View Page |
| Nitrite Test The nitrites portion of the reagent strip provides a rapid screening test for the presence of gram-negative bacteria that are often responsible for urinary tract infections. Although urine cultures are still needed to confirm the diagnosis and monitor any urinary tract or kidney infection, the need for a culture may not be obvious because in some cases of early bladder infection, the symptoms may be vague or the patient may be asymptomatic. Diagnosis and treatment of cystitis (bladder infection) is important because if left untreated it may result in kidney damage, impairment of renal function, hypertension and/or septicemia. | View Page |
| Bladder Infections Bladder infections are usually caused by gram-negative bacteria. These bacteria reduce nitrates derived from food to nitrites when urine remains in the bladder three to four hours, sufficient time for this reaction to occur. Nitrite is not present in urine under normal circumstances. When present, nitrites react with p-arsanilic acid to produce a diazonium compound. The diazonium compound in turn couples with 3-hydroxy-1,2,3,4 tetrahydrobenzo-(h)-quinolin to produce a pink color. A first morning, clean, voided midstream specimen is optimal for detecting nitrites in urine. | View Page |
| Test Sensitivity This test is sensitive to 0.06-0.1 mg/dL nitrite ion in urines with a low specific gravity and ascorbic acid concentrations of less than 25 mg/dL. Pink spots or pink edges should not be interpreted as a positive result because some medications can color urine red or turn red in an acid environment. Any degree of uniform pink color should be considered positive, suggesting the presence of 105 organisms/mL. Detection of low levels of nitrite ion may be enhanced by comparing the activated test strip to a white background. It is important to note that color development is NOT proportional to the number of bacteria present. The test is specific for nitrites and does not react with any other substances normally present in urine. Negative results do not necessarily rule out a urinary tract infection because yeasts or gram-positive bacteria unable to reduce nitrites may be the causative agent. | View Page |
| Clinical Significance Early detection of bacteria is important in order to prevent cystitis from developing into inflammation or infection involving the kidney and renal pelvis. The nitrite portion of the test strip can be used to screen individuals who are at risk for developing urinary tract infections, such as diabetics, persons with recurrent infections, or pregnant women. The test is also useful in evaluating the success of antibiotic therapy that is used to treat a bladder infection. | View Page |
| The nitrite portion of the test strip can be used to: (Choose ALL of the correct answers) | View Page |
| Granulocytic white blood cells Granulocytic white blood cells in a urine sample suggest the presence of a urinary tract infection. Granulocytes, which include neutrophils, basophils and eosinophils, contain esterases. These esterases catalyze the strip reagent indoxylcarbonic acid ester to release indoxyl. Indoxyl reacts with a diazonium salt to produce a purple color. The intensity of the color produced is proportional to the amount of enzyme present. | View Page |
| Clinical Significance Using the esterase test in conjunction with pH, protein and nitrite provides a combination of tests which can screen for the presence of bacterial infection. | View Page |
| To screen for urinary tract infections leukocyte esterase should be coupled with: (Choose ALL of the correct answers) | View Page |
| Introduction Human papillomavirus (HPV) is a frequently occurring viral sexually transmitted infection (STI). HPV infections often present with mild signs and symptoms or are asymptomatic, and do not always progress to a disease state. HPV infections are especially frequent in adolescents and young adults, between the ages of 15-24 years. About 20 million Americans are currently infected with HPV and there are several million new infections each year in the U.S. Since HPV infections are so common, the CDC believes that most sexually active adults are infected at some point during their lifetime. Though the majority of HPV infections are transient and do not result in serious disease, clinicians are concerned about the HPV infections that cause cervical and other anogenital carcinomas. Diagnosis and management of HPV has changed dramatically with the introduction of DNA methods for diagnosis of HPV infections and vaccines for the prevention of HPV infections. Understanding HPV characteristics and diagnostic testing is important for clinical laboratory scientists. | View Page |
| HPV Vaccines The FDA has approved vaccines to prevent HPV infections in young women: Gardasil, Merck & Co, quadrivalent vaccine, FDA approved June 2006 Cervarix, GlaxoSmithKline Biologicals, bivalent vaccine, FDA approved October 2009Vaccination is recommended for young women and immunization before the onset of sexual activity. If the vaccine is received after a HPV infection, it protects the individual from other HPV types that they have not been infected with, assuming these types are included in the vaccine. Gardasil and Cervarix are both recombinant vaccines administered in a set of three doses. Once vaccinated, regular cervical screening is required to detect infections and abnormal cytology from HPV types not contained in vaccines. | View Page |
| HPV Vaccines; Gardasil and Cervarix GardasilGardasil HPV vaccine contains HPV types 6, 11, 16, and 18. Those vaccinated are protected against the two viral types (6 and 11) that cause about 90% of condolymas and against the two viral types (16, 18) that cause approximately 70% of cervical cancer. Gardasil vaccination is recommended for girls 11 and 12 years old. The vaccine can be given to girls as early as 9 years of age and catch-up immunization is recommended for women ages 13-26 years.CervarixCervarix HPV vaccine contains only two HPV types, 16 and 18. Infection with either of these types is responsible for the majority of cervical carcinoma. It is approved for vaccination of women and girls ages 10-25 years. | View Page |
| HPV as a Sexually Transmitted Infection HPV viruses infect the skin that lines the lower genital tract and mouth; viral DNA replicates in the squamous epithelium. Condom use reduces the risk of transmitting HPV but does not completely prevent transmission. Since the virus infects skin cells, there can be transmission in unprotected skin-to-skin contact.Symptoms of HPV viral infection are rare; the majority of individuals infected are unaware that they have contracted HPV. Most infections spontaneously resolve within a few months without the formation of lesions. | View Page |
| HPV and Cervical Cancer It is recognized today that high-risk HPV(HR-HPV) types cause cervical cancer. Cervical cancer is the second most common cancer in women worldwide. According to the CDC, in the U.S., approximately 11,000 women are diagnosed each year with cervical cancer. Worldwide, there are about 450,000 new cases each year; approximately 200,000 women die from cervical cancer yearly. The HPV infection can linger for years in cervical cells and eventually convert normal cells into malignant cells. Cervical cancer occurs when a HR-HPV infection is not naturally resolved or cleared by the immune system. Approximately 10% of women with a HR-HPV infection develop these lingering infection complications. | View Page |
| Additional Cervical Cancer Factors It is well known that some women with HPV infections will develop cancerous or precancerous conditions, while some infected women will not. Most scientists believe other patient conditions and factors along with HPV infection can increase the chances of a women developing cancer. Some of the factors associated with an increased risk of developing cervical cancer in those with a HPV infection are: Smoking Immunosuppression Chlamydia infection Diet low in fruits and vegetables Obesity Extended use of oral contraceptives Multiple pregnancies Low socioeconomic status Family history of cervical cancer | View Page |
| HPV infection can linger for years in cervical cells and eventually convert normal cells into malignant cells. | View Page |
| Inappropriate Use of HPV DNA Testing HPV DNA testing should not be used as an STI screening test; there is no treatment for HPV as an STI for those who test positive. HPV DNA testing should not be performed to screen for infection prior to vaccination. This would unnecessarily increase the cost of vaccination. HPV DNA testing is not approved or recommended for routine cervical screening for women less than 30 years of age. For adolescents (women 20 years or younger), HPV DNA testing should not be follow-up on abnormal Pap smear test results. HPV is ubiquitous and most young women have infections after becoming sexually active. Most individuals, especially young women, resolve the infection without any intervention. The process of cervical carcinogenesis comprises many years or even decades and most HPV infections do not result in cancer. Unnecessary colposcopy procedures will be performed if young women are tested for HPV. Lesions that are found and treated with cervical excision procedures can increase the risk of premature delivery and low-birth-weight babies. As noted above, HPV DNA testing is recommended for women of any age postcolposcopy of an AGC or ASC-H Pap smear report. The DNA testing is postcolposcopy, not Pap smear follow-up. These lesions may be from non-HPV infections and HPV testing provides information on follow-up options. | View Page |
| What is the recommended HPV DNA testing for Michelle, a 19-year-old female with ASC-US Pap smear report? | View Page |
| References Cervical Cancer: Prevention and Early Detection. American Cancer Society. Available at http://www.cancer.org/docroot/CRI/content/CRI_2_6x_cervical_cancer_prevention_and_early_detection_8.asp. Accessed December 1, 2011. Cervista HPV, Cervista HPV – Invader Technology. HOLOGIC. Available at http://www.cervistahpv.com/laboratory/invadertechnology.html. Accessed December 1, 2011.Chin-Hong PV, Klausner JD. Diagnostic tests for HPV infection. Medical Laboratory Observer. October 2004:10-16.Cobo F, Concha A, Ortiz M. Human papillomavirus (HPV) type distribution in females with abnormal cervical cytology. A correlation with histological study. Virology Journal. 2009;3:60-66.Cox JT, Moriarty AT, CastlePE. Commentary on statement on HPV DNA test utilization. American Journal Clinical Pathology. 2009;131:770-773.HPV Vaccine Information for Clinicians. Centers for Disease Control and Prevention. Available at http://cdc.gov/std/hpv/stdfact-hpv-vaccine-hcp.htm. Accessed December 1, 2011.Human Papillomavirus (HPV) Natural History. American Society for Colposcopy and Cytological Pathology. Available at http://www.asccp.org/hpv_history.shtml. Accessed December 1, 2011.Human Papillomavirus (HPV) Vaccines. National Cancer Institute. Available at http://www.cancer.gov/cancertopics/factsheet/prevention/HPV-vaccine. Accessed December 1, 2011.Human papillomaviruses and Cancer: Questions and Answers. National Cancer Institute Fact Sheet. Available at http://www.cancer.gov/cancertopics/factsheet/risk/hpv. Accessed December 1, 2011.Hybrid Capture 2 Technology. QIAGEN - Sample & Assay Technologies. Available at http://www1.qiagen.com/hpv/hc2technology.aspx. Accessed December 1, 2011.Markowitz LE, Sternberg M, Dunne EF, et al. Seroprevalence of human papillomavirus types 6, 11, 16, and 18 in the United States: national health and nutrition examination survey 2003-2004. Infectious Disease. 2009;200:1059-1067.Molecular Diagnostics Fundamentals, Methods, and Clinical Applications. Leal Buckingham and Maribeth L. Flaws. Philadelphia:FA Davis Company, 2007.Schutzbank TE, Jarvis C, Kahmann N, et al. Detection of high-risk papillomavirus DNA with commercial invader-technology-based analyte-specific reagents following automated extraction of DNA from cervical brushings in Thinprep media. Journal of Clinical Microbiology. 2007;45:4067-4069.Solomon D, Papillo JL, Davey DD. Statement on HPV DNA test utilization. American Journal of Clinical Pathology. 2009;131:768-769.Vernick JP, Steigman, CK. The HPV DNA virus hybrid capture assay: what is it—and where do we go from here? Medical Laboratory Observer. Mar 2003:8-13.Voss JS, Kipp BR, Campion MB et al. Comparison of fluorescence in situ hybridization, hybrid capture 2 and polymerase chain reaction for the detection of high-risk human papillomavirus in cervical cytology specimens. Analytical and Quantitative Cytology and Histology. 2009;31:208-216. | View Page |
| Human Papilloma Virus (HPV) and Mycobacterium Human papilloma virus (HPV) is estimated to be the most common sexually transmitted infection in the United States. Digene's hybrid capture assay for HPV received approval by the Food and Drug Administration (FDA) in 2003. Only in recent years have other manufacturers, such as Third Wave Technologies, added this virus to their testing capabilities.Mycobacterium species represented another desirable target for molecular testing. Although some improvements in cultivation and staining techniques had been realized through the incorporation of broth media and fluorochrome staining, identification is still hampered by the growth rate of the organism. Gen-Probe first marketed probes that would allow identification of tuberculosis, M. avium-intracellulare, and M. gordonae in culture positive specimens. These probes greatly streamlined the workup of culture positive specimens.Of great interest to both clinicians and infection control practitioners, is the direct detection of Mycobacterium in clinical specimens. Gen-Probe received FDA approval for its AMPLIFIED MTDâ product for this specific application (in smear positive specimens) in 1995. This method employs isothermal transcription mediated amplification; the amplicons are detected using the same hybridization as the culture confirmation tests. | View Page |
| Identification of Staphylococcus aureus with Peptide Nucleic Acid (PNA)-Fluorescence In Situ Hybridization (FISH) Staphylococcus aureus, particularly methicillin resistant strains (MRSA), have represented a likely target for molecular development, particularly in blood cultures. As more institutions implement patient screening protocols for MRSA, replacement of routine culture methods with molecular assays has gained increasing attention.PNA-FISH assays provide for the definitive identification of Staphylococcus aureus from positive blood culture vials. Peptide nucleic acid fluorescent in-situ hybridization is a relatively straight forward procedure that does not involve amplification and has limited equipment requirements. Procedurally it is easy to perform with minimal hands on time.PNA is a synthetic imitator of a nucleic acid sequence in which the backbone is a pseudopeptide rather than a sugar. PNA behaves similarly to DNA and will bind to complementary nucleic acid strands. A PNA probe is constructed, utilizing a complementary, hybridizing sequence for a known nucleic acid target sequence. The probe is typically bound to a fluorescent protein as a means of visualizing/detecting the target. In one commercially available method, once a blood culture vial demonstrates gram-positive cocci in clusters, a drop of the blood culture broth is added to fixation solution on a slide. Heat or methanol is used to fix the smear. After fixation, probe that targets species-specific ribosomal RNA is added to the smear, which is then cover-slipped.Slides are then incubated at 55oC. Post incubation, slides are immersed in a preheated wash solution and coverslips gently removed. After incubation in the wash solution, smears are air dried; a drop of mounting medium is added and the slide is cover-slipped again.The slides are examined with a fluorescent microscope, utilizing specific filters. Green fluorescing cocci in clusters are identified as Staphylococcus aureus. This identification would be available, depending on the routine identification system utilized, potentially 24 hours earlier than the norm.A significant number of blood cultures that demonstrate gram-positive cocci in clusters yield coagulase negative staphylococci (CNS), which represent potential contaminants, rather than significant infection. What is the significance of differentiating blood cultures that contain S. aureus from those that are growing CNS in a much earlier timeframe?Studies have shown that IF the differentiation of CNS from S. aureus is effectively communicated to clinicians and pharmacy/antimicrobial stewardship teams, active assessment can occur utilizing defined exclusion criteria for those patients whose cultures yielded CNS rather than S. aureus. In scenarios where contamination rather than infection is indicated, vancomycin can be discontinued earlier, and length of hospital stay is also shortened. Reduced antibiotic exposure, reduced risk of development of resistance, and reduced cost are all potential benefits. | View Page |
| References BD GeneOhm™ MRSA [package insert]. Quebec, Qc, Canada: BD Diagnostics; 2009. Available at: http://www.bd.com/geneohm/english/products/pdfs/mrsa_pkginsert.pdf. Accessed February 22, 2012.Bonetta L. Prime time for real-time PCR. Nature Methods. 2005;2:305-312. Available at: http://www.nature.com/nmeth/journal/v2/n4/full/nmeth0405-305.html. Accessed February 22, 2012.Boughton B. Universal PCR Screening for MRSA May Cut Costs, Reduce Infection. In Medscape Medical News. Available at: http://www.medscape.com/viewarticle/708813. Accessed February 22, 2012.CDC Response: A Year in Review. Centers for Disease Control and Prevention Website. Available at: http://www.cdc.gov/h1n1flu/yearinreview.htm. Accessed February 22, 2012.Centers for Disease Control and Prevention. Evaluation of Rapid Influenza Diagnostic Tests for Detection of Novel Influenza A (H1N1) Virus ---United States, 2009. Morbidity and Mortality Weekly Report. August 7, 2009;58(30):826-829. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5830a2.htm. Accessed February 22, 2012.Department of Biochemistry. University at Buffalo, School of Medicine and Biomedical Sciences Website. Available at: http://www.smbs.buffalo.edu/bch/Labs/SinhaLab/Protocols/RT-PCR.pdf. Accessed February 22, 2012.Desjardins M, Guibord C, Lalonde B, Toye B, Ramotar K. Evaluation of the IDI-MRSA Assay for the Detection of Methicillin-Resistant Staphylococcus aureus from Nasal and Rectal Specimens Pooled in Selective Broth. J Clin Microbiol. 2006 April;44(4):1219-1223. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448652/. Accessed February 22, 2012.Eastwood K, Else P, Charlett A, Wilcox M. Comparison C. difficile detection methods. J Clin Microbiol. 2009;doi:10.1128/JCM.01082-09. Available at: http://jcm.asm.org/cgi/content/short/JCM.01082-09v1Farley JE, Stamper PD, Ross T, Cai M, Speser S, Carroll KC. Comparison of the BD GeneOhm Methicillin-Resistant Staphylococcu aureus (MRSA) PCR Assay to Culture by Use of BBL CHROMagar MRSA for Detection of MRSA in Nasal Surveillance Cultures from an At-Risk Community Population. J Clin Microbiol. 2008;46(2):743-746. Available at: http://jcm.asm.org/content/46/2/743.full. Accessed February 22, 2012.Forrest GN, Mehta S, Weeks E, Lincalis DP, Johnson JK, Venezia RA. Impact of Rapid In Situ Hybridization Testing on Coagulase Negative Staphylocci Positive Blood Cultures. J Antimicrob Chemother. 2006;58(1):154-158. Available at: http://jac.oxfordjournals.org/content/58/1/154.full. Accessed February 22, 2012.Garcia LS, Isenberg HD, eds-in-chief. Clinical Microbiology Procedures Handbook. 2nd ed. Washington, DC: ASM Press; 2007.Hindiyeh M, Hillyard DR, Carroll KC. Evaluation of the Prodesse Hexaplex Multiplex PCR Assay for Direct Detection of Seven Respiratory Viruses in Clinical Specimens. Am J Clin Pathol. 2001;116:218-224. Available at: http://ajcp.ascpjournals.org/content/116/2/218.full.pdf. Accessed February 22, 2012.Hunt M. Real Time PCR. University of South Carolina School of Medicine Website. Available at: http://pathmicro.med.sc.edu/pcr/realtime-home.htm. Accessed February 22,2012.Interim Guidance for Influenza Surveillance: Prioritizing RT-PCR Testing in Laboratories. Centers for Disease Control and Prevention Website. Available at: http://www.cdc.gov/h1n1flu/screening.htm. Accessed February 22, 2012.Interim Guidance for the Detection of Novel Influenza A Virus Using Rapid Influenza Diagnostic Tests. Centers for Disease Control and Prevention Website. Available at: http://www.cdc.gov/h1n1flu/guidance/rapid_testing.htm. Accessed February 22, 2012.Levenson D. Molecular Testing for Respiratory Viruses. In Clinical Laboratory News. March 2008: Vol 34, No 3. Washington, DC: AACC Press; 2008. Available at: http://www.aacc.org/publications/cln/2008/mar/Pages/cover1_0308.aspx. Accessed February 22, 2012.Morshed MG, Lee MK, Jorgensen D, Issac-Renton JL. Molecular methods used in clinical laboratory: prospects and pitfalls. FEMS Immunol Med Microbiol. 2007;49:184-191. Available at: http://www.canlyme.com/morshed_pcr.pdf. Accessed February 22, 2012.Paillard F, Hill CS. Direct nucleic acid diagnostics tests for bacterial infectiousdiseases: Streptococcal pharyngitis, pulmonary tuberculosis, vaginitis, chlamydial and gonococcal infections. MLO-online. 2004;10-15. Available at: http://www.mlo-online.com/articles/0104/mlo0104coverstory.pdf. Accessed February 22, 2012.PCR: an outstanding method. Roche Website. Available at: http://www.roche.com/pages/facets/pcr_e.pdf. Accessed February 22, 2012.Persing DH, ed-in-chief.Molecular Microbiology, Diagnostic Principles and Practice. 2nd ed. Washington, DC: ASM Press; 2010.Pfaller MA. Molecular Approaches to Diagnosing and Managing Infectious Diseases: Practicality and Costs. Emerg Infect Dis. 2001;eid0702. Available at: http://wwwnc.cdc.gov/eid/article/7/2/70-0312_article.htm. Accessed February 22, 2012.Rossney AS, Herra CM, Brennan GI, Morgan PM, O'Connell B. Evaluation of the Xpert Methicillin-Resistant Staphylococcus aureus (MRSA) Assay Using the GeneXpert Real-Time PCR Platform for Rapid Detection of MRSA From Screening Specimens. J Clin Microbiol. 2008;46(10):3285-3290. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2566096/. Accessed February 22, 2012.The 2009 H1N1 Pandemic: Summary Highlights, April 2009-April 2010. Centers for Disease Control and Prevention Website. Available at: http://www.cdc.gov/h1n1flu/cdcresponse.htm. Accessed February 22, 2012.Timeline of PCR and Roche. Roche Website. Available at: http://molecular.roche.com/About/pcr/Pages/PCRTimeline.aspx. Accessed February 22, 2012. | View Page |
| 2009 - Swine Flu The 2009 H1N1 influenza virus was first detected in the United States on April 15, 2009.The virus was a unique combination of influenza virus genes never previously identified in either animals or people; they were most closely related to swine-lineage H1N1 viruses (hence the designation of "swine influenza"). However, epidemiological investigations of initial human cases did not identify exposures to pigs and it became apparent that this new virus was circulating among humans and not among U.S. pig herds.By April 21, 2009, the Centers for Disease Control and Prevention (CDC) began working on development of a new vaccine effective against this new strain. On April 24, 2009, the CDC uploaded complete gene sequences of the 2009 H1N1 virus to a publicly accessible international influenza database. At the same time vaccine development was occurring, work was also being done at CDC to help laboratories more quickly identify the 2009 H1N1 virus in patient samples. A real time PCR assay developed by the CDC was cleared for use by the Food and Drug Administration (FDA) under an Emergency Use Authorization (EUA) on April 28, 2009.The development of an effective, rapidly performed molecular assay was critical, because a CDC evaluation of non-molecular rapid influenza assays indicated that while these tests were capable of detecting the novel H1N1 strain when present in high concentrations, the overall sensitivity was low. Positive results with these assays were useful, but negative results did not rule out infection with influenza. | View Page |
| Which statement about the 2009 H1N1 virus is TRUE? | View Page |
| Previous Methodologies: Antigenic Detection of Toxin and Glutamate Dehydrogenase (GDH) Toxin assaysThe most common laboratory tests for the detection of C. difficile are enzyme immunoassays (EIA) for the detection of C. difficile toxin A and toxin B. The immunoassays are simple to perform, provide rapid results, and are easily incorporated into the workflow of most laboratories. Sensitivities of these tests do NOT compare favorably to culture, cell cytotoxicity neutralization assay (CCNA), or molecular methods. There are many test kits commercially available for detection of C. difficile toxins. Results are available in 15 minutes to 2 hours, depending on the assay. Initially, toxin A was thought to be the toxin responsible for the majority of the effects of C. difficile disease, so most early kits only detected toxin A. With the realization that there are strains that produce aberrant or no toxin A (A-) that are known to produce infection, and more recently toxin B negative (B-) strains, it is now recommended to use kits detecting BOTH toxins.Glutamate Dehydrogenase (GDH) assaysPublished studies have indicated that toxin immunoassays, by themselves, may not provide adequate sensitivity of detection. GDH assays initially attracted attention as a possible means to provide a rapid but more sensitive means for screening for C. difficile.GDH is an enzyme produced by C. difficile. EIAs negative for the GDH antigen have been associated with high negative predictive values. However, positive results are not necessarily associated with a toxin producing strain. A second assay on GDH positive samples is required to confirm the presence of a toxigenic strain. Initially, CCNA assays were recommended as the confirmatory method of choice; molecular methods (PCR for the toxin gene) were subsequently explored for this purpose. | View Page |
| Staphylococcus aureus Virulence Factors S. aureus is the most pathogenic member of the genus Staphylococcus; it possesses several factors that contribute to its virulence: Structural components of its cell wall function as a protective barrier, aid in adherence to mucous membranes, and allow the organism to resist phagocytosis. The production of several different toxins Enterotoxins A, D, F (TSST1) Exfoliative toxin ( causing scalded skin syndrome Cytolytic toxins (causing cell & tissue damage). Production of enzymes Catalase – distinguishes staphylococci from streptococci Coagulase – distinguishes S. aureus from other staphylococci Hyaluronidase & lipase – aid in skin colonization/infection spread Beta-lactamase – breaks down the beta-lactam antibiotics, e.g., penicillins, cephalosporins, carbapenems and monobactams. | View Page |
| Clinical significance of Staphylococcus aureus In general, the infection that develops is dependent on the virulence of the particular strain, the inoculum size, and immune status of the host. Staphylococcal infections are typically suppurative, producing abscesses filled with pus and damaged leukocytes surrounded by necrotic tissue. Skin infections range from superficial - boils, carbuncles and furuncles, to bullous impetigo; largely opportunistic infections that develop as a result of previous injury e.g., cuts, burns, surgical wounds - and scalded skin syndrome (extensive exfoliative dermatitis; also known as Ritter's Disease). Other major infections include pneumonia, osteomyelitis (localized infection of bone), and septic arthritis. S. aureus also causes food poisoning as a result of ingestion of food contaminated with an enterotoxin producing strain (enterotoxins A&D) and the potentially fatal toxic shock syndrome, a multisystem disease most often associated with the use of highly absorbent tampons. Toxic shock syndrome is attributed to another toxin (enterotoxin F – TSST1) released by certain strains of S. aureus.Human staphylococcal infections usually remain localized by the normal host defenses. Foreign objects (fomites) such as sutures or intravenous (IV) lines - are readily colonized by S. aureus from skin and can allow the organism to spread systemically via the blood stream – bacteremia/septicemia - leading to more serious infections. Staphylococcal pneumonia is becoming a frequent complication of influenza. Whatever the mode of entry, the invasive nature of S. aureus always poses the threat of more serious deeper tissue invasion and/or bacteremia and hematogenous spread. | View Page |
| The pathogenicity of Staphylococcus aureus, as well as the frequency with which this organism produces infections, can be attributed to: | View Page |
| Risk Factors Medical conditions that lead to immunosuppression increase the risk of MRSA infection. Participating in contact sports, sharing towels or other personal items, living in areas with unsanitary conditions or living in crowded conditions, such as in dormitories or military barracks may also increase the risk of becoming infected with MRSA. Healthcare workers, the very young and the elderly are at increased risk of infection. Skin punctures and/or wounds increase infection risk by providing an entry point for the organism. Hospitalized patients are at risk of infection from healthcare workers with contaminated hands and from other MRSA carriers. Intravenous (IV) lines, surgical sites and implanted device can be easily contaminated with MRSA if infection control precautions are not followed. | View Page |
| Future Perspectives (continued) Judicious use of antimicrobials, especially in outpatient settings, can help control the emergence of CA-MRSA and limit the acquisition of additional resistance by existing strains. Regardless of origin, minimizing antibiotic selective pressure that favors the development of resistant strains is essential to controlling the emergence of these strains in both hospital and community settings.The development of vaccines to prevent S. aureus infection in both healthcare and community settings holds great promise. Recently (2007) a vaccine based on an immunotherapeutic licensed to Merck has shown promising results in a clinical trial against hospital acquired S. aureus infections, while Nabi Biopharmaceuticals, Ft. Lauderdale, FL, are developing the "next generation" of StaphVax, which will contain antigen against S. aureus detoxified Panton Valentine Leucocidin and the cytolytic alpha-toxin. | View Page |
| Enzyme Immunoassay Methods The most common laboratory tests for detection of C. difficile are enzyme immunoassays (EIA) for detection of C. difficile Toxin A and Toxin B. The immunoassays are simple to perform and provide rapid results. However the sensitivities of these tests are not as good as culture, CCNA, or molecular methods. Only liquid stool samples should be processed. Due to the fact that the colonization rate is high, a positive result with a normal stool sample proves that the patient is colonized with C. difficile but not necessarily infected. There are many test kits available commercially for detection of C. difficile toxins. Results are available in 15 minutes – 2 hours depending on assay. Initially Toxin A was thought to be the toxin responsible for the majority of the effects of C.difficile disease, so most early test kits only detected Toxin A (based on monoclonal anti-Toxin A antibodies) but with the realization that there are strains that produce aberrant or no Toxin A (A-) that are known to produce infection, and more recently Toxin B negative (B-) strains, it is now recommended that a kit is used that detects both toxins. | View Page |
| Treatment of CDI/CDAD The first step in treating patients with CDAD is to discontinue the causative agent wherever possible. The choice for initial antibiotic therapy depends on the severity of disease. Oral vancomycin or metronidazole remain the mainstays of therapy for C. difficile infection, with vancomycin reserved for patients with more severe disease and/or those who have not responded to metronidazole. Metronidazole is currently favored in guidelines from the CDC on the basis of cost and concern that oral vancomycin promotes colonization with vancomycin-resistant Enterococcus. Oral fluids (water and electrolytes) may be necessary to counteract fluid loss as a result of excessive diarrhea, which can quickly lead to dehydration. Patients with fulminant disease and toxic megacolon may require colectomy. Recurrence of C. difficile infection (CDI) is becoming an increasing problem. Most recurrences happen 7 - 14 days after completion of therapy, suggesting relapse rather than re-infection. If a patient develops a second episode of CDI following initial successful treatment, it is recommended that if possible, the same drug be used to treat the second episode. Contributing factors to recurrent CDI include: Continuing exposure to organisms either through re-infection (via contaminated environment or poor hand hygiene) or an endogenous source, such as C. difficile spores in GI tract. An inability to mount an adequate anti-Toxin A IgM and/or IgG antibody response (i.e., poor host immune response); a likely reason why CDI affects an increasingly elderly population. Unfortunately a vicious cycle can arise whereby the initial treatment prescribed, vancomycin or metronidazole, significally disrupts normal colonic flora reducing colonization resistance and leaving the patient vulnerable to the next recurrent episode.Other treatments including the use of probiotics or anion-exchange resins to absorb toxins, may work in some cases but none work in every case.The goal of all treatment is to reestablish normal colonic flora so as to control C. difficile (over)growth. | View Page |
| Disinfection & Control of C. difficile Infection C. difficile spores resist dessication for months and are known to persist on hard surfaces for up to 5 months. Spores persist even after exposure to air. Epidemic strain B1/NAP1/027 is known to hyper-sporulate, a virulence-associated characteristic of outbreak strains. Healthcare workers are an important vector for transmission as they may carry the spores on their hands or clothing. Alcohol-based hand sanitizers are very effective against non-sporulating organisms but do not kill C. difficile spores or remove the organism from the hands. The CDC recommends thorough hand washing using soap and water for care givers and family members alike.Patients with C. difficile infection (CDI) should be isolated to a single room with a bathroom or cohorted (roomed) together. Staff treating infected patients should use PPE (gowns & gloves) and wash hands after removing gloves. The use of gowns helps to prevent contamination of clothing. Surfaces should be decontaminated using a solution of 10% sodium hypochlorite (bleach), this is effective in reducing environmental contamination in hospital rooms. The CDC recommends the use of bleach for cleaning patient and staff rooms during outbreaks. Control strategies involving reinforcement of Infection control practices rather than drug restriction are more effective. These practices include: Proper education of staff members involved in care of CDI patients Better isolation compliance Use of gloves Frequent and thorough hand washing Environmental decontamination | View Page |
| Clostridium Species Clostridium are gram-positive or gram-variable, spore-forming, catalase-negative anaerobic bacilli. More than 100 species are currently recognized, though relatively few are encountered in properly collected clinical specimens from humans. There are three types of infection associated with Clostridium species: Non-invasive: Toxin-mediated Invasive: Progressive infection with tissue destruction Purulent disease: Closed space (e.g., in the peritoneal cavity) mixed infection with multiple organisms.Clostridium are well known as the agents of these classic toxin-mediated diseases : DISEASE TOXIN INVOLVED CAUSATIVE ORGANISM Tetanus or "lock jaw" Tetanospasmin Clostridium tetani Myonecrosis/Gas gangrene Exotoxins Clostridium perfringens Botulism (severe food poisoning) Botulin Clostridium botulinum | View Page |
| Clostridium difficile Most Clostridium infections arise from endogenous sources. That is, many of the Clostridium species that are associated with disease in humans are part of the normal intestinal microflora, which is true of Clostridium difficile.The organism was originally isolated in 1935 as a component of the normal intestinal flora of healthy newborns. It was dubbed difficile because the organism grows slowly and is difficult to culture. Early investigators also noted that the organism produced a potent toxin, but the relationship between C. difficile antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC) was not elucidated until the 1970's. PMC is an inflammatory disease of the colon caused by toxins of Clostridium difficile. Normal intestinal flora is an important factor in host response to an infectious microorganism. Resistance to intestinal infection is significantly reduced when there is a reduction in the normal flora as a result of antibiotic treatment. The most common manifestation of this decreased host resistance is the development of PMC. | View Page |
| C. difficile Toxin A and Toxin B Clostridial toxins are among the largest bacterial toxins reported to date and C. difficile produces two potent toxins: Toxin A ((TcdA), an enterotoxin and Toxin B (TcdB), a cytotoxin. It is the production of these toxins in the gastrointestinal tract that ultimately leads to disease. There is a relationship between toxin levels, the development of pseudomembranous colitis (PMC), and the duration of diarrhea. Levels of Immunoglobulin G against TcdA correlate directly with protection from disease following colonization, suggesting that a robust immune response is sufficient for protection from C. difficle-associated diarrhea (CDAD). The role of TcdB is not as well understood. Naturally occurring Toxin A negative/Toxin B positive (TcdA-TcdB+) strains have been identified from clinical isolates, which are capable of causing disease, even extensive PMC, suggesting a role for TcdB in CDAD. Toxin A had always been regarded as more important than Toxin B in infection. However, recent work utilizing mutant C. difficile, strains which did not, or could not produce Toxin A, and which were capable of producing very serious disease has led researchers to completely rethink the roles of Toxin A and Toxin B in CDAD. Toxin B was found to be responsible for the more serious damage to intestinal cells. In addition to the primary virulence factors (Toxin A and Toxin B ), Clostridium difficile also produces a third toxin, binary toxin (CDT). The prevalence of CDT in clinical isolates varies widely and its clinical relevance and role in pathogenicity are still not well defined. | View Page |
| Pathogenisis of C. Difficile-Associated Diarrhea Clostridium difficile is the leading cause of hospital-acquired diarrhea in the United States, with the number of cases rising annually over the last three decades. This is largely due to the increased frequency of antibiotic usage, the development of better detection methods, and the fact that hospital environments are increasingly contaminated with spores of C. difficile. The definition of C. difficile diarrhea includes > 6 episodes of non-formed diarrheic stool per 24 hours, along with prior antibiotic treatment. At least three events must occur in the pathogenesis of C. difficile-associated diarrhea (CDAD): Alteration of the normal fecal flora Colonic colonization with toxigenic C. difficile Growth of the organism with elaboration of its toxins"Colonization resistance" is the term used to describe the mechanism by which indigenous flora control overgrowth of C. difficile. This resistance may be compromised by the use of antimicrobial compounds, underlying illness, or therapeutic procedures. Infection begins with the ingestion of either the organism itself or spores, usually via the fecal-oral route. Spores in particular are able to survive the acidity of the stomach and germinate in the colon to produce vegetative organisms. Toxinogenic strains subsequently produce Toxin A, Toxin B, and/or the Binary Toxin leading to colitis, pseudomembrane formation, and watery diarrhea. Significant complications of the clinical disease associated with infection are hypoalbuminemia, toxic megacolon (acute toxic colitis with dilatation of colon), and pseudomembranous colitis (PMC). | View Page |
| Strain BI/NAP1/027 In the early 2000's researchers in Quebec, Canada noticed an increase in the number of colectomies being performed as a result of an increase in the frequency and severity of CDAD. At around the same time, doctors at the Centers for Disease Control and Prevention (CDC) were receiving reports of increased frequency and severity of disease in the United States. There were also reports of more disease and more severe forms of C. difficile infection in other areas of the world, suggesting that the experience was very widespread and possibly global. In 2004, analysis of this hypervirulent strain showed a very characteristic strain that had previously been rare but was responsible for the majority of the more serious outbreaks. This strain – BI/NAP1 /027 – has several designations depending on which biological property was examined :- BI: Restriction Endonuclease Analysis (USA)- NAP1: North American PFGE Type 1 based on polyacrylamide gel electrophoresis (USA) - 027: Ribotype 027 by polymerase chain reaction (Europe)There are 5 unique features associated with this strain – It produces the classic toxins A & B, but faster and at much higher levels than other strains. It is Toxinotype III in contrast to the more typical clinical isolates, which tend to be Toxinotype 0. tcdC is deleted from the PaLoc, possibily explaining the observed increase in toxin production. It produces the binary toxin CDT, but its role is still unclear. It exhibits high level in vitro resistance to fluoroquinolones. | View Page |
| Risk factors for Clostridium difficile Infection The incidence of C. difficile infection varies considerably but is increasing worldwide, largely due to widespread use of broad-spectrum antibiotics. The risk factors associated with C. difficile infection and colitis are: Antimicrobial use length of course multiple antibiotics Hospitalization length of stay illness & weakness presence of spores in hospitals and long-term care facilities(LTCF) Age Advanced age > 65 (weakened immune systems Young children (immature immune systems) Underlying disease (weakened immune system) Use of proton pump inhibitors, gastric acid suppressants, or anti-ulcer medications that decrease acidity levels in stomach/GI tract, which can alter normal flora and allow C. difficile to proliferate Chemotherapeutic drugs (weakened immune system) Laxative use Gastrointestinal (GI) surgery or non-surgical invasive procedures such as intubation | View Page |
| Clostridium difficile-associated Diarrhea Clostridium difficile-associated diarrhea (CDAD) is a unique hospital infection that occurs almost entirely in patients who have received previous antimicrobial treatment. Anaerobic gut flora are crucial to colonization resistance, so any disruption of the normal colonic flora (through illness, therapeutic procedures or, most commonly, antibiotic use) is essential to the pathogenesis of C. difficile infection. The association of CDAD with antibiotic use is significant. Early attention (1970s) focused on clindamycin but later on (1980s,1990s & continuing today) the cephalosporins, especially third generation, and broad spectrum penicillins (e.g., amoxycillin/ampicillin) were also implicated. The risk of CDAD is increased if C. difficile is resistant to the particular antimicrobial. In the case of clindamycin, C. difficile resistance is variable. Risk of infection due to a clindamycin-resistant strain increases with use of the drug. For the third generation cephalosporins, C. difficile is universally resistant; thus, any toxigenic strain is capable of causing CDAD during cephalosporin use. Other less commonly implicated antibiotics are the macrolides, e.g., erythromycin, azithromycin, clarithromycin. However, prolonged courses of any antibiotics will increase the risk of disease. Even those antibiotics used to treat colitis (metronidazole, for example) have sometimes been reported to cause CDAD.The fluoroquinolones have been in use since the 1980s. Ciprofloxacin was approved in 1987, but it is only in recent years with the emergence of the epidemic strain 027/NAP1/BI, which is resistant to the fluoroquinolones, that this class of drugs has been implicated in Clostridium difficile disease. The fluoroquinolones were initially considered to be low risk but their use has been increasing, both with hospital inpatients and in the community, and fluoroquinolones are now implicated as a risk factor for C. difficile infection. The newer fluoroquinolones, e.g., gatifloxacin, moxifloxacin, have better activity against anaerobes, but poor in vitro activity against C. difficile, thus increasing the likelihood of CDAD. The CDC now recommends that all fluoroquinolones, as a class, be used sparingly as each poses an increased risk for CDAD. | View Page |
| C. difficile disease is more likely to occur when: | View Page |
| Selection of Drugs for Testing The panel of drugs selected for testing must take into consideration a number of factors: The laboratory performing the testing The number of drugs that can practically be tested Infection control requirements Drugs that are available in formularies Susceptibility patterns exhibited locally Consideration of the body site of the infection and whether the drug is an appropriate therapy | View Page |
| About This Course This course will provide you with basic information about bloodborne pathogens, the regulations that govern safe work practices when handling blood and other potentially infectious body fluids, and necessary precautions that must be taken to minimize your risk of exposure to these infections. | View Page |
| The Hepatitis B Vaccination The hepatitis B vaccine is one of the most important ways to prevent infection with HBV. The vaccine is safe and very effective, if the series is completed. The series includes three shots in the upper arm given over a six-month period.The present recombinant vaccine uses genetically-altered bakers yeast and contains no blood components.Side effects are minimal. Symptoms such as temporary soreness at the injection site, mild fever, or joint pain may occur, but are rare.The OSHA standard requires that employers provide the vaccine free of charge to you if your occupation puts you at risk for hepatitis B infection. You may decline the vaccine. If you choose not to have it, you will be asked to sign a Declination Statement. If you initially decline, but later choose to have the vaccine while still an employee, you will be able to receive it at that time. However, if your job puts you at risk for occupational exposure to HBV, you are strongly urged to receive the vaccine when it is first offered to you unless you have previously received the complete hepatitis B vaccination series, antibody testing has revealed that you are already immune, or you have been told not to receive the vaccine for medical reasons. | View Page |
| Importance of Hand Hygiene Frequent handwashing is one of the most important measures that you can take to help control the spread of infections. Hands should be washed:As soon as gloves are removed Before and after direct patient contact After using the toilet Before eating or drinking Anytime hands are contaminated Before leaving the work area | View Page |
| What Happens After HBV Infection? After the exposure, there is an incubation period that lasts between 45 and 180 days, with an average of 90 days. Many individuals with acute HBV will have no symptoms at all. Some will have a mild illness with loss of appetite, nausea and vomiting, and fatigue. About 30% of infected individuals will develop clinical hepatitis with jaundice (yellow discoloration of the skin and eyes) due to liver dysfunction. | View Page |
| Who is infected? Patients infected with HBV or other bloodborne organisms can appear healthy, so you can't tell whose blood is infectious.So treat all:bloodbody fluidssecretions (except sweat)excretionsnon-intact skinmucous membranes as if they were infectious. | View Page |
| Blood Needed For Transmission The amount of blood needed to cause HBV infection is very small. One milliliter of blood contains up to 100 million infectious particles. | View Page |
| How common is HBV? There are approximately 800,000 to 1.4 million individuals with chronic hepatitis B in the United States. Worldwide it is estimated that there are 350 million people infected with HBV, which contributes to an estimated 620,000 deaths worldwide each year.*The annual number of occupational infections has decreased 95% since hepatitis B vaccine became available in 1982, from more than 10,000 in 1983 to less than 400 in 2001.*** Reference: Hepatitis B information for health professionals. CDC website. Available at: http://www.cdc.gov/hepatitis/HBV/HBVfaq.htm#overview. Accessed October 28, 2011.**Reference: Exposure to blood: What healthcare personnel need to know. CDC website. Available at: http://www.cdc.gov/ncidod/dhqp/pdf/bbp/Exp_to_Blood.pdf. Accessed October 28, 2011. | View Page |
| Chronic Hepatitis B Infection About 10% of adults who are infected with hepatitis B go on to chronic hepatitis, which lasts for years. Chronic hepatitis B eventually can cause scarring of the liver (known as cirrhosis), liver failure, and, more rarely, liver cancer.While these complications are uncommon, they serve to emphasize the need to take necessary precautions in the workplace to prevent exposure to HBV. | View Page |
| What Causes HIV Infection? HIV infection is caused by the human immunodeficiency virus. The infection occurs when HIV enters a person's bloodstream, where it attacks and kills the helper T-cells. Helper T-cells are part of a group of white blood cells known as lymphocytes that are essential for fighting off infections.As the numbers of these cells decreases, so does the body's ability to fight infection. | View Page |
| How Common is HIV Infection? There are approximately 1.1 million individuals in the United States who are infected with HIV.Worldwide, it is estimated that there are over 33 million persons with HIV/AIDS, with most of these individuals living in sub-Saharan Africa.The Centers for Disease Control and Prevention (CDC) has documented 57 cases of HIV infection in health care workers through December 2001.*Reference: Preventing occupational HIV transmission to healthcare personnel. CDC website. Available at: http://www.cdc.gov/hiv/resources/factsheets/hcwprev.htm. Accessed October 26, 2011. | View Page |
| What Happens After HIV Infection? Days to weeks after exposure, the patient may begin to complain of fever, headache, and fatigue. This may also be accompanied by a rash.For the first several months after the infection, the exposed individual may be HIV-antibody negative and the disease may not be detected. However, the individual is still infective and can transmit the disease during this period.The disease may remain silent in the patient for months to years, even with no treatment.When the immune system is weakened enough, the patient will develop opportunistic infections and be classified as having acquired immunodeficiency syndrome (AIDS). | View Page |
| Information From The Centers for Disease Control and Prevention (CDC) Regarding Hepatitis C According to the CDC, persons born between 1945-1965 account for three-fourths of the cases of HCV infection. This group is also at greatest risk for hepatocellular carcinoma and other HCV-related liver diseases. The CDC recommends a one-time HCV testing for all persons born between 1945-1965.Although there is still no vaccine for HCV, there are therapies that can halt progression of the disease and provide sustained clearance of the virus following treatment. For this reason, it is critical to detect infection as soon as possible. If an infected person progresses to liver failure, a liver transplant may be required.Health care workers must be diligent in their adherence to standard precautions in order to prevent occupationally-acquired HCV infection. | View Page |
| What Happens After Hepatitis C Infection? Five to twelve weeks after the exposure, some individuals may develop flu-like symptoms, including nausea, vomiting, tiredness and loss of appetite. These may last from weeks to months.Approximately 80% of infected individuals will have no symptoms at all. | View Page |
| How Common is HCV? About 4 million people in the United States alone are estimated to have hepatitis C antibodies (evidence of prior infection). Sixty percent or more of patients are unaware of their infections.HCV may now be responsible for 15 - 20% of new acute hepatitis cases and half of the cases of liver cancer occurring in the U.S. | View Page |
| Human infection of the schistosomes occurs following penetration of what morphologic form into the skin? | View Page |
| Houseflies are a possible transmission for which of these categories of parasites? | View Page |
| Arrange the following life cycle phases of Diphyllobothrium latum in order beginning with human transmission: | View Page |
| Contact with infected cat feces is responsible for the transmission of: | View Page |
| Serologic methods have been developed to identify which of these parasites? | View Page |
| Which of the following is the recommended protocol for collecting stool samples in order to rule out a parasitic infection? | View Page |
| A 20 year-old female was admitted into the hospital complaining of 10 to 15 bloody mucous stools per day, fever, gastrointestinal disturbances, abdominal pain, and nausea. The preliminary O & P report went out as "Probable Entamoeba histolytica trophozoites and cysts, confirmation pending." This patient is most likely suffering from: | View Page |
| Which parasite listed here is capable of crossing the placenta and causing serious harm to fetus? | View Page |
| Immunocompromised patients, such as those with AIDS are at an increased risk of contracting which of the following conditions? | View Page |
| Match each parasite listed below with its corresponding respective associated condition: | View Page |
| A 32 year old male was seen in the emergency room with gastrointestinal discomfort. Upon questioning the patient it was learned that he first began feeling ill after spending a day at the park where he swam and played volleyball barefooted. He first noticed a lesion on his foot. Later, he developed vague respiratory symptoms. Now his largest complaint is severe abdominal pain along with occasional vomiting. This patient is most likely suffering from: | View Page |
| This stool parasite measures 135 µm by 50 µm and is the causative agent of: | View Page |
| This stool parasite measures 55 µm by 50 µm and is the causative agent of: | View Page |
| A 38 year-old male presented to the E.R. complaining of severe cough, chest pain, shortness of breath and general fatigue. Parasitic examination of his bloody sputum revealed this suspicious form. The patient is most likely suffering from: | View Page |
| Which of the following symptoms are associated with an infection of the parasite pictured below? | View Page |
| This suspicious form is associated with which of the following conditions? | View Page |
| Perianal itching is the major symptom of infection with both forms of the organism pictured here. This parasite is the causative agent of: | View Page |
| This suspicious form, recovered in stool, measures 165 µm by 65 µm. It is responsible for causing: | View Page |
| Match each parasite named below with its respective primary symptom: | View Page |
| With which of the following conditions is this suspicious form associated? | View Page |
| The process resulting in the transformation of a cyst into a trophozoite is known as: | View Page |
| Arrange the basic steps in the intestinal ameba life cycle in order starting with transmission to a human host: | View Page |
| Human infection with flukes is called: | View Page |
| Dracunculus medinensis belongs to this category of parasites: | View Page |
| Humans serve as accidental hosts in the life cycles of which of these this parasites? | View Page |
| The eggs of Necator americanus are basically indistinguishable from the eggs of: | View Page |
| Label the morphologic structures on this parasite form: | View Page |
| Label the morphologic structures on this parasite form: | View Page |
| Label the morphologic structures on this parasite form: | View Page |
| Label the morphologic structures on this parasite form: | View Page |
| A 21 year old male presented in the emergency room with symptoms resembling a liver infection. The patient complained of abdominal pain, fever, cough, nausea, vomiting and constipation alternating with diarrhea. Further examination revealed the presence of a hepatic abscess. This suspicious form was recovered following parasitic examination of a sample from the abscess and measures 20 µm. What condition is the patient most likely suffering from? | View Page |
| A 35 year old male presented to the local clinic complaining of abdominal cramps, severe diarrhea, and intestinal gas discomfort. A stool was collected for parasite examination. It was foul-smelling and light colored in nature. This suspicious form was recovered and measured 10 µm by 12 µm. The patient is infected with: | View Page |
| A 43 year old female presented to her doctor for a routine check-up. Her only complaint was that she had been experiencing watery stools that occasionally contained pus and blood. Examination revealed tenderness in her abdomen. A stool for parasite study was sent to the lab. Two suspicious forms were seen. The oblong form on measured 53 µm by 60 µm whereas the rounder form measured 45 µm by 37 µm. Use the pulldown boxes to identify each picture: | View Page |
| A 58 year old male, who recently returned from an extensive overseas business trip to Africa, presented to the local clinic complaining of nausea, vomiting, and an achy feeling all over his body. At first he thought it was just the flu, but it persisted. The doctor ordered a battery of tests including blood smears for parasitic study. This suspicious form was recovered. The patient is most likely suffering from: | View Page |
| A 16 year old male champion athlete went to his doctor complaining of a persistent cough, fever, bloody diarrhea and overall weakness. Upon questioning the patient, it was learned that he had recently competed in a freshwater swimming competition in the Caribbean. Examination revealed a dermatitis on the patient's right calf. A battery of tests were ordered including a CBC, chemistry profile, and a stool for culture and parasitic examination. The CBC revealed the presence of eosinophilia. The other hematology and chemistry tests were unremarkable. The culture was negative. This suspicious form was seen on all parasite preparations made from the stool sample submitted. This form measures 165 µm by 68 µm. This patient is most likely suffering from an infection with: | View Page |
| A 65 year old Asian female presented to the emergency room exhibiting severe abdominal pain, fever and diarrhea. Examination revealed an enlarged liver that was tender to the touch. Patient history revealed that the woman worked in a fish processing plant for years prior to moving to the United States. Her diet was heavy in raw fish. Stool and duodenal contents were collected and sent to the laboratory for cultures and parasite examination. The cultures were unremarkable. This suspicious form was seen in both specimen types. It measures 27 µm by 14 µm. This patient is most likely suffering from: | View Page |
| A 27 year old female graduate student recently returned from South America, where she completed a nature study of the rain forest. She spent months "living off the land." The woman went to her physician seeking treatment for a sinus infection, which she thought was responsible for several recent bouts of diarrhea. Upon questioning the patient, the doctor decided to collect stool for culture and parasitic examination. The stool culture was reported as "no enteric pathogens isolated." This suspicious form was seen on both wet preparations and on permanent stain. It measures 17 µm. The identify of this form is most likely: | View Page |
| A 10 year old male presented to the local Appalachian Mountain clinic complaining of vomiting, fever and severe abdominal pain. Patient history revealed that the child lives in the area in substandard conditions and receives only one balanced meal per day. A stool was collected and submitted for parasite study. This suspicious form, measuring 50 µm by 35 µm was found. This patient is most likely infected with: | View Page |
| A 40 year old male recently completed a two-week hiking expedition in Russia. Upon his return to the United States, the man presented to his physician complaining of severe foul-smelling diarrhea and abdominal discomfort. The doctor immediately suspected a parasitic infection and ordered stool for examination. The sample was loaded with this suspicious form that averaged 13 µm in length. This patient is most likely suffering from: | View Page |
| A 54 year old Finnish male presented at the local clinic with abdominal pain, weight loss, overall weakness and digestive discomfort. Patient history revealed that the man's diet was rich in raw fish. A complete blood count (CBC) was performed and revealed macrocytic anemia. A stool for parasitic examination was ordered. This suspicious form was seen upon initial screening of the sample. It measures 77 µm by 48 µm. This patient is most likely suffering from an infection with: | View Page |
| A 40 year old male just returned from a six-month tour of the Far East. He went to his doctor upon his return complaining of weakness, diarrhea, fever and cough. Upon questioning the patient it was learned that he spent many an evening swimming in the various local fresh water ponds. The doctor, suspicious of a parasitic infection, ordered a stool for examination. Two suspicious forms were seen: form 1 is roundish and measures 77 µm by 62 µm. Form 2 is long and ladder-like and lays on the edge of form 1. What are these two structures? | View Page |
| A 6 year old female presented to the local clinic complaining of intense perianal itching and diarrhea. The doctor ordered a cellophane tape prep and stool for routine culture and parasitic examination. The cellophane tape prep revealed suspicious form on the left. The stool culture was negative. The form on the right was seen upon examination of the stool for parasites, which measures 10 µm. Label these two suspicious forms: | View Page |
| A 27 year old West African immigrant went to the local clinic complaining of fever, chills, and joint pain. The physician immediately ordered blood for parasitic examination. The Giemsa-stained thin blood smear revealed the three suspicious forms below. This patient is most likely suffering from an infection with: | View Page |
| A 29 year old male steak house owner from Arizona presented to his doctor complaining of weight loss, abdominal pain and diarrhea. Patient history revealed that the man eats all of his meals at his restaurant and his favorite meat is rare sirloin steak. The man also noted that he had recently been on anti-parasitic medication. The doctor ordered a stool for parasitic examination. These two suspicious forms were seen. The patient is most likely suffering from an infection with: | View Page |
| Parasitized animals that may serve as a source of infection for humans are called: | View Page |
| The artifact that when seen is indicative of intestinal inflammation and is characteristic of a number of parasitic infections is known as (a): | View Page |
| This parasite, found in stool, measures 60 µm by 45 µm. Name that parasite! | View Page |
| This suspicious form, that measures 25 µm, was recovered in an eye sample. It is associated with which of the following diseases? | View Page |
| This parasite measure 50 µm by 30 µm. Its common name is: | View Page |
| A 35 year old man presented to his doctor with fever, diarrhea, abdominal pain and epigastric discomfort. Upon questioning the patient, it was learned that he travels extensively on business and loves to try new kinds of raw fish. The patient is most likely suffering from: | View Page |
| What term is defined as the presence of arthropods in or upon a human host: | View Page |
| A parasite that takes up residence inside the human body host is called a/an: | View Page |
| The presence of parasites in human blood is termed: | View Page |
| Which of the following is NOT a characteristic of Burkholderia pseudomallei? | View Page |
| Location Where Organisms Naturally Occur, Disease Produced, and Mode of Transmission These organisms can be encountered outside of a bioterrorism event and produce human disease. It's important to be familiar with the geographic areas where these organisms naturally occur and the how disease is transmitted.Bacillus anthracis: Bacillus species inhabit the soil, water, and airborne dust. Anthrax is the disease produced, which is transmitted to humans via direct contact with infected herbivorous animals. This is where the disease is primarily encountered. Anthrax is controlled in animals in the United States, so the disease is rare. In humans, most cases are cutaneous infections found in people that handle animals and animal products, including veterinarians and agricultural workers. Anthrax is consistently present in the animal population of some geographical regions, such as Iran and Pakistan, but only small numbers of animals experience the disease at any given time. Yersinia pestis: Y. pestis is found primarily in rodents, but can also be found in several animal species, such as cats, rabbits, camels, squirrels. Animal to human transmission most commonly occurs via a flea bite, causing the most common form of the disease known as the bubonic plague. Human-to-human transmission occurs by either flea bite or respiratory droplets. This causes an overwhelming disease known as pneumonic plague, which is the most likely form that would be implicated in the event of a bioterrorist attack. Human cases of the plague continue to occur in many countries, including Africa, the southwestern United States, parts of Asia, and the former Soviet Union. Francisella tularensis: Many animals, including rodents, rabbits, deer, and raccoons act as host for this organism. Humans and domesticated animals, such as horses, cattle, cats, and dogs can become infected. The infection is transmitted to domesticated animals by ticks and biting flies. Humans are most commonly infected from the bite of an infected tick or fly. Other means of infection include direct contact with the blood of infected animals when skinning game, eating contaminated meat, drinking contaminated water, or inhaling the organisms produced by aerosols. F. tularensis carries a high risk of laboratory acquired infection and documented cases of infection have occurred. Most cases of tularemia are reported in the southern and south-central United States. | View Page |
| Location Where Organisms Naturally Occur, Disease Produced, and Mode of Transmission, continued: Brucella species: Brucella is distributed in nature worldwide and found in domesticated and wild animals, such as cattle, sheep, and pigs. Infection with Brucella species, known as brucellosis, is caused in humans by exposure to infected animal fluids or food products. This includes ingesting non-pasteurized dairy products, such as milk or cheese, inhaling aerosols, and skin contact with the fluids of infected animals. Brucellosis poses an increased risk of occupational exposure to laboratory, veterinary, and slaughterhouse workers. Brucella is the most commonly reported laboratory-associated bacterial infection.Burkholderia mallei and B. pseudomallei: Most Burkholderia are found in soil, but B. mallei is only found in mammals. B.mallei is the causative agent for Glanders which primarily affects animals such as donkeys, mules, and horses. Horses, the organism's natural host, are highly susceptible to infection. Human infection is rare and usually occurs in people working with infected animals or laboratory workers handling the organism. The organism is endemic in Africa, Asia, the Middle East, and Central and South America, and usually enters via the eyes, nose, mouth, abrasions or cuts in the skin, or through inhalation. B. pseudomallei is found in soil and water and can accidentally infect animals, plants, and rarely humans. It is the causative agent of melioidosis, which is endemic in areas of southeast Asia, Taiwan, and northern Australia. The organism generally enters through cuts in the skin, ingestion of contaminated water, or by inhalation of an aerosol. | View Page |
| Match the organism to the disease produced outside a bioterrorism event. | View Page |
| Category A Agents: Reasons Why They May be Used to Create Public Health Emergencies Anthrax (B. anthracis): Inhalation of anthrax spores is virtually 100% fatal Spores can remain infectious for decadesBotulism: Most lethal toxic agent known Toxin could be used to contaminate food supplies Can be aerosolized in enclosed areasPneumonic Plague (Y. pestis): Aerosolized in large amounts Short incubation period, usually in less than three days, and invariably fatal without early and effective antimicrobial therapy Untreated, fatality rate exceeds 90% Disease is spread from direct exposure to respiratory droplets of infected humansSmallpox: Highly contagious and deliberate spread by aerosol is extremely infectious Mass panic would be createdTularemia (F. tularensis): Highly contagious and easily spread An aerosol containing as few as 25 organisms can cause infection Easily penetrates the smallest breaks in the skinViral Hemorrhagic Fever: Causes internal and external bleeding and would likely cause great panic and easily spread by direct contact with body fluids or respiratory droplets Outbreak due to bioterrorist attack could lead to mass illness and death | View Page |
| Genetic Components of Influenza A Subtype H1N1 The influenza A H1N1 2009 virus is regarded as being genetically different from the normally prevelent seasonal influenza A viruses. Novel influenza A virus was originally referred to as "swine flu" because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs in North America. However, influenza A, subtype H1N1 virus actually has genetic components of human, avian, and swine influenza A combined into one virus; a process called antigenic shift. This virus contains: Two genes from flu viruses from pigs in Europe and Asia One avian, or bird, gene One human geneThis type of virus is called a "quadruple reassortment" virus. Pigs serve as intermediate hosts for influenza A viruses since the respiratory tract of pigs contains receptors for not only swine influenza A viruses, but also avian and human influenza A viruses. Since pigs are also susceptible to avian influenza A viruses from turkeys, ducks, and wild waterfowl, the genetic mixing of swine and avian viruses has been documented over the past 15 years. An additional reassortment may occur with the inclusion of human influenza A genes when pigs are exposed to farmers with respiratory tract infections. The current 2009 H1N1 virus thus represents the most recent example of swine influenza A virus reassortment that contains both avian and human influenza A genes.Reference 1 | View Page |
| About the Virus The 2009 H1N1 virus, like other influenza A viruses, is an enveloped, single-stranded RNA virus. Influenza viruses are members of the family Orthomyxoviridae and are divided antigenically into 3 major types, A, B, and C. Influenza A viruses have the ability to undergo continuous antigenic changes, whereas Influenza B viruses reassort to a much lesser degree and influenza C viruses are antigenically stable. Due to their ability to undergo antigenic changes, influenza A viruses can cause more infections with greater morbidity in the human population than influenza B or C viruses. Influenza A viruses are subtyped based on two glycoprotein spikes expressed on their surface:1) Hemagglutinin (HA)2) Neuraminidase (NA)HA, a viral attachment protein, helps to facilitate the attaching of the virus onto ciliated epithelial cell receptors in the respiratory tract. NA is an enzyme that facilitates the release of virus particles from the infected cell surface. | View Page |
| About the Virus (continued) Susceptibility to an influenza virus strain is dependent on the immune status of the human host, since our bodies become immune only to the strains that we have been exposed to previously (either naturally or by vaccination). The lack of previous exposure to this subtype resulted in the rapid spread and increased number of infections, especially in the younger population. Respiratory infections occurred, even among those individuals who had received the seasonal flu vaccine because that vaccine was not formulated to protect against the influenza A 2009 H1N1 subtype. | View Page |
| Epidemiology of the Virus The Influenza A 2009 H1N1 virus spreads from person to person in a similar way to the seasonal flu in previous years.The primary route of influenza virus transmission and infection are by respiratory droplets and aerosols. Transmission may also occur via contaminated hands (person-to-person) and surfaces. Infected individuals can shed the virus and spread Influenza A 2009 H1N1 to others anywhere from 1 day prior to getting sick up until 5-7 days after symptoms arise. This range of viral shedding can be even longer in children and in some individuals who are immunocompromised. | View Page |
| Seasonal Influenza A Seasonal influenza typically peaks during the winter months. Influenza viruses can cause illness in any age group, but serious illness and death are associated most often with: –Children <2 years of age Adults age 65 and older Individuals of any age who have underlying medical conditions that could make infection with influenza virus more serious The CDC estimates that 5 - 20% of U.S. citizens are infected with influenza viruses each year. About 36,000 deaths are associated with influenza infection complications yearly.•• | View Page |
| How 2009 H1N1 Differs from Seasonal Flu Viruses The 2009 Influenza A H1N1 virus is both similar and different from previous influenza A viruses that have caused seasonal flu in recent years. The symptoms associated with the H1N1 virus are very similar to those of other influenza A viruses causing seasonal flu. One difference between the influenza A 2009 H1N1 virus and seasonal influenza A viruses is the time of year in which the infection is at its peak. The influenza 2009 H1N1 virus was prevalent during warmer weather months in 2009, whereas the peak time for seasonal influenza viruses is winter months.Another way in which the H1N1 virus differs from seasonal flu viruses is the age group that is most affected. The number of cases and severity of the disease has been greater in the younger population, whereas most seasonal influenza virus-related deaths have been reported in those age 65 and older. | View Page |
| How Severe is the Illness? •Influenza A 2009 H1N1 virus-related symptoms range from mild to severe. Many infected individuals are able to recover without medical treatment. Occasionally, some individuals require hospitalization, and these patients receive supportive care and antiviral treatment. Serious infections from the 2009 H1N1 virus have resulted in some patient fatalities, usually due to secondary bacterial pneumonia or other respiratory complications.It is important to note that approximately 70% of the individuals that require hospitalization due to H1N1 infection, have also had one or more previously recognized underlying medical condition that may compromise an effective immune response. These conditions include, but are not limited to: diabetes heart disease asthma kidney disease neurocognitive diseases pregnancy | View Page |
| Which of the following is NOT a typical symptom associated with the 2009 H1N1 virus? | View Page |
| Guidelines for Diagnostic Testing and Treatment According to the CDC guidelines, patients with clinical illness consistent with uncomplicated influenza who reside in an area where influenza viruses are circulating may not require diagnostic influenza testing for clinical management. Most mild cases of H1N1 infection are self-limiting and do not require confirmation. However, if a patient is hospitalized due to the severity of the symptoms, or if the diagnosis of the patient will provide needed information to the physician to direct clinical care, infection control decisions, or management of close contacts, diagnostic influenza testing should be done. In any case, if a decision to use antiviral treatment is made, the treatment should commence as soon as possible, without waiting for the results of confirmatory diagnostic tests. | View Page |
| How long can influenza A viruses survive on a hard surface? | View Page |
| Treatment Options for H1N1 Infection Most patients who have suspected or confirmed cases of H1N1 infection have a mild, uncomplicated, self-limited illness that may not require antiviral treatment. If infected individuals have a normal immune system, they should be able to recover from the infection with symptomatic treatment only and without antiviral therapy. However, it is the decision of the patient's physician whether to treat or not to treat. The CDC provides this decision tree as a guideline if the illness is mild and uncomplicated:The CDC suggests that patients with suspected or confirmed influenza should be treated if: They are hospitalized as a result of the illness They are at risk for severe disease including these patients: Patients that have certain medical conditions, such as asthma, diabetes, heart disease, or patients with weakened immune systems that may exacerbate the infection. Children younger than 2 years old Adults 65 years or older Pregnant women or women up to 2 weeks post-partum They have a progressive or complicated illness characterized by signs of: lower respiratory tract disease such as hypoxia or abnormal chest x-ray CNS complications such as encephalitis Complications of low blood pressure including shock or organ failure Myocarditis Invasive secondary bacterial infection The treatment options indicated for the 2009 H1N1 infection include oseltamivir (brand name Tamiflu®), an oral tablet, and zanamivir (brand name Relenza®), an inhaled antiviral agent.Reference: Centers for Disease Control and Prevention. Updated interim recommendations for the use of antiviral medications in the treatment and prevention of influenza for the 2009-2010 season. December 7, 2009. Available at: http://www.cdc.gov/h1n1flu/recommendations.htm. Accessed January 18, 2010. | View Page |
| H1N1 Vaccine When vaccine first became available to protect against infection with H1N1 virus, supplies were limited and those who were in high risk groups were given priority for receiving the vaccine. However, as of late December 2009, supplies increased substantially so that sufficient vaccine was available for everyone who chose to receive it. The CDC recommends that all individuals, regardless of age or health status, receive the vaccine. Individuals, age 65 or older with no medical risk factors, are less likely to get sick with H1N1, however, severe illness and deaths have occurred in all age groups. Therefore, it is prudent for everyone to be vaccinated. The vaccine is produced in the same manner as the vaccine against seasonal influenza and has the same assurance of safety that has been proven with the seasonal influenza vaccine. One caution that should be noted is that persons with known allergies to eggs may experience allergic reactions to the H1N1 vaccine, as they would with any influenza vaccine. These individuals should consult with a physician before receiving the vaccine. | View Page |
| Prevention of H1N1 Infection In addition to vaccination against the influenza A 2009 H1N1 virus, the CDC recommends the following preventive measures to prevent person-to-person spread of infection during the influenza season. Wash hands often with soap and water for 15-20 seconds or cleanse hands with an alcohol-based hand sanitizer.Avoid touching mucous membranes such as the nose, mouth, and eyes.Stay home if you have a fever and flu-like illness until 24 hours after the fever has resolved.Avoid close contact with sick individuals.Avoid large crowds during an epidemic. | View Page |
| Which of the following would be effective methods to reduce the risk of becoming infected with the H1N1 virus? | View Page |
| Tuberculosis Infection TB infection is usually followed by an immune response and latency after exposure. In about 5-10% of cases, the latent period progresses to an active infection.Infection occurs when a susceptible person inhales droplet nuclei containing Mycobacterium tuberculosis and the organism reaches the alveoli of the lungs. The minimal infectious inoculum may be as low as one viable organism.About 2-12 weeks after infection, the immune system limits multiplication of additional bacteria and the immunological test becomes positive.Latent tuberculosis infection (LTBI) is the stage when the viable organism remains in the body; the individual has no symptoms and is noninfectious.Most persons infected with M. tuberculosis do not experience clinical illness and are noninfectious. About 5-10% of persons who are infected and are not treated will develop active TB during their lifetime. The risk for progression is highest during the first several years after infection.Most often, M. tuberculosis infects the lungs. However, it can infect almost any organ in the body, including bones and joints. Tuberculosis meningitis is a TB infection that occurs outside the lungs with devastating consequences, most often in young children and patients with AIDS. | View Page |
| How Tuberculosis is Spread Mycobacterium tuberculosis is spread through infectious droplet nuclei. When a person infected with pulmonary tuberculosis coughs, sneezes, shouts, or sings, the infectious particles are expelled into the air. The risk of infection is related to both concentration of infectious droplet nuclei and duration of exposure. Laboratory workers are at risk when an infectious aerosol is generated while handling liquid cultures, during preparation of frozen sections, and when performing autopsies on infected patients. | View Page |
| High-Risk Infection Groups Geographic areas with high incidence of tuberculosis include Africa, Asia, eastern Europe, Latin America, and Russia. Persons at higher risk for exposure to and infection from Mycobacterium tuberculosis include: Frequent travelers to areas of the world where tuberculosis is endemicResidents and employees of high-risk congregate settings such as correctional facilities, long-term care facilities, and homeless sheltersHealth care workers who serve high-risk patients or have unprotected exposureMedically underserved and low-income populationsInfants, children, and adolescents exposed to adults in high-risk categories | View Page |
| The descriptions listed below all relate to tuberculosis (TB). Match each of the descriptions with the item in the drop-down box that it describes. | View Page |
| TST Interpretation and Classification The TST interpretation depends on the measured diameter of the induration and the clinical status of the patient.An induration of 15 or more millimeters is considered positive in all persons.An induration of 10 or more millimeters is considered positive in patients in the high-risk progression groups and in mycobacteriology laboratory workers.An induration of 5 or more millimeters is considered positive in the high-risk infection groups. | View Page |
| False Positive TST reactions A false positive reaction is a TST induration >5 millimeters even though the person is not infected with Mycobacterium tuberculosis. Some causes are: previous BCG vaccination,infection with nontuberculosis mycobacteria,incorrect TST administration or interpretation. | View Page |
| TST False Negative Reactions A false-negative reaction is no induration after a TST, even if the person is infected with Mycobacterium tuberculosis. Some causes of this are: Weakened immune systemRecent, old, or overwhelming TB infectionImmature immune system (<6 months of age)Some viral illnessesRecent live-virus vaccinationsIncorrect TST administration or interpretation | View Page |
| Blood Assay for Mycobacterium tuberculosis (BAMT) The BAMT is a blood test that can detect LTBI.The BAMT has the advantage of no false positive results due to previous BCG vaccination or infection with nontuberculosis mycobacteria.The BAMT was approved by the FDA in 2005. | View Page |
| Two-Step Skin Testing If an initial skin test is classified as negative, a second skin test should be administered 1 - 3 weeks after the first result was read.If the second test is positive, it probably represents a boosted reaction from a past infection. Response to tuberculin decreases over time. The initial TST stimulates the immune system, so that there is an immune response to a subsequent TST.If the second test is negative, the person is classified as not infected.Two-step testing eliminates the false-negative test results due to a weakened immune system.The two-step skin testing is not used in contact investigations or in other circumstances in which ongoing transmission of M. tuberculosis is suspected. | View Page |
| The two step TST has no false positive reactions due to infection with nontuberculosis mycobacteria or BCG vaccination. | View Page |
| Airborne Infection Isolation Room Practices Patients with active TB should be assigned to single-patient rooms in which entry of HCWs and visitors is controlled.All HCWs use a N95 disposable respirator.Visitors may be offered respiratory protection and should be instructed by HCWs on the use of the respirator before entering.The room has requirements for controlled ventilation, negative pressure, and air filtration.Each isolation room should have a private bathroom. | View Page |
| Biosafety Level Criteria and Requirements for Handling Specimens Suspected of Containing Mycobacterium tuberculosis All specimens suspected of containing M. tuberculosis (including specimens processed for other microorganisms) should be handled in a Class I or II biological safety cabinet (BSC). Appropriate personal protective equipment (PPE) must be used. At a minimum, this includes gloves and fluid-resistant laboratory coat or gown. Non-aerosol-producing manipulations (eg, preparing direct smears for acid-fast staining when done in conjunction with training and periodic checking of competency) can be performed using biosafety level-2 (BSL-2) practices and procedures, containment equipment, and facilities. BSL-3 practices, safety equipment, and facility design and construction are applicable to microbiology laboratories that work with indigenous or exotic agents with a potential for respiratory transmission, and which may cause serious and potentially lethal infection. If the laboratory is propagating and manipulating cultures for M. tuberculosis, BSL-3 practices, containment equipment, and facilities are required. Barriers include controlled access to the laboratory and ventilation requirements that minimize the release of infectious aerosols from the laboratory. Secondary barriers should include self-closing double-door access and negative airflow into the laboratory. Exhausted air must not be recirculated. Work surfaces must be decontaminated, using the laboratory-approved disinfectant, upon completion of procedures, immediately following a spill, and at the end of the work shift, if the surface was recontaminated since the last cleaning. Laboratory equipment should be routinely decontaminated.Hands must be washed upon completion of work with potentially infectious materials and before leaving the laboratory. | View Page |
| Which of the following statements is true regarding hyposegmented neutrophils? | View Page |
| The hematology analyzer reported an elevated white blood cell count and flagged for manual review due to the suspected presence of immature cells. What is the arrowed cell's identity, and what name is given to its inclusion? | View Page |
| Conditions Associated with Hypersegmented Neutrophils There are a number of conditions in which hypersegmented neutrophils may be seen, such as megaloblastic anemias (including folic acid deficiency and pernicious anemia). Individuals who are receiving chemotherapy or have long-term chronic infections may also have hypersegmented neutrophils.The cells seen in these conditions would be classified as pathological since the body is responding abnormally as a result of either a deficiency of a component needed for DNA production or because of the toxic effect that chemotherapy drugs have on DNA. | View Page |
| Normal Band Forms vs. Pelger-Huet Bands Recognition and diagnosis of the inherited form of Pelger-Huet anomaly is important because many of these Pelger-Huet neutrophils may be classified as bands, therefore; increased numbers of bands might be erroneously reported in these patients. Since increased numbers bands frequently indicate infection, reporting Pelger-Huet cells as normal band forms could result in inappropriate treatment for infection. Pelger-Huet cells have denser nuclear chromatin than neutrophilic band forms. | View Page |
| Conditions Associated with Hyposegmented Neutrophils The presence of hyposegmented neutrophils can be an acquired phenomenon, as a result of severe infection, burns, malignancy, chemotherapy or other drugs such as sulfonamides. When the causative agent is removed, the cells will return to normal. Percentages of neutrophils affected will vary in this condition. Hyposegmented neutrophils as an aquired phenomenon are known as pseudo-Pelger-Huet cells. | View Page |
| Cytoplasmic Vacuolation Vacuoles are areas of the cytoplasm which do not stain with Wright's stain and appear as holes in the cytoplasm. Their composition may vary; some will contain remnants of bacterial digestion, autodigestion in an aging cell, while others may contain fat. It is not possible to differentiate the various types of vacuoles on Wright stained smears using light microscopy. Vacuoles may be seen occasionally in an aging granulocyte (degenerative vacuolation), but are seen more frequently and are significant in cases of bacterial infection and septicemia. | View Page |
| Toxic Granulation and Vacuolation Vacuoles are frequently seen in conditions such as infection or burns when toxic granulation is also present. The cell in this image exhibits toxic vacuolation as well as toxic granulation. Note: Toxic vacuolation and toxic granulation are classified as reactive and not pathologic since the body is responding normally in an effort to rid itself of infection caused by bacteria. | View Page |
| Classification Vacuoles, toxic granulation and degranulation are classified as reactive since the body is responding normally in an effort to rid itself of infection caused by bacteria. Morphological changes related to aging are also classified as reactive. | View Page |
| Döhle Bodies, continued Döhle bodies are seen in a number of conditions, including:infections burns measles leukemia chemotherapyDöhle bodies are only present when the body is responding to unusually severe stress or stimulus. This severe stress may cause the cytoplasm of some cells to mature improperly. Their presence does not aid in the diagnosis of the disorders in which they are found, but they are frequently seen along with toxic granulation and/or vacuoles in cases of infection or burns. | View Page |
| Toxic Granulation Toxic granulation is manifested by the presence of large granules in the cytoplasm of segmented and band neutrophils in the peripheral blood. The color of these granules can range from dark purplish blue to an almost red appearance. Toxic granules are actually azurophilic granules, normally present in early myeloid forms, but are not normally seen at the band and segmented stages of neutrophil maturation. These granules contain peroxidases and hydrolases. Toxic granulation is seen in cases of severe infection, as a result of denatured proteins in rheumatoid arthritis or, less frequently, as a result of autophagocytosis. Infection is the most frequent cause of toxic granulation. This phenomenon may be seen in cells which also contain Döhle bodies and/or vacuoles. Cells containing toxic granules may have decreased numbers of specific granules. Note: Cells containing only a few specific granules, with or without toxic granules, are said to be degranulated. The nucleus in degranulated cells may often be round-bilobed, smooth and pyknotic. This type of nucleus is the result of aging and will disintegrate soon. Increased basophilia of azurophilic granules simulating toxic granules may occur in normal cells with prolonged staining time or decreased pH of the stain. The blue arrow in the image points to a neutrophil with toxic granulation. Döhle bodies are also present in the cell, indicated by the red arrows. | View Page |
| Toxic granulation is seen most frequently in: | View Page |
| Chediak-Higashi Anomaly Chediak-Higashi anomaly is a rare autosomal recessive disorder. It results from a mutation of the gene LYST which encodes a protein with multiple phosphorylation sites. This defect causes a cellular abnormality involving the fusion of cytoplasmic granules. Early in neutrophil maturation normal azurophilic granules form, but they fuse together to form megagranules. Later during the myelocyte stage, normal specific granules form. The mature neutrophils contain both normal specific granules and abnormal azurophilic granules. These large abnormal granules can be seen in the cytoplasm of neutrophils, eosinophils, basophils, monocytes and lymphocytes. These abnormal granules are able to kill bacteria in neutrophils and monocytes; however, the process is much less effective than in normal cells in part, because these neutrophils have impaired locomotion. For these reasons, individuals with Chediak-Higashi have recurrent infections. An accelerated lymphoma-like phase occurs, with lymphadenopathy, hepatosplenomegaly, and pancytopenia. Death often occurs at an early age. | View Page |
| Select the letter representing the cell that can be seen in increased concentrations in the peripheral blood smear during immediate hypersensitivity reactions: | View Page |
| The cell containing the inclusions indicated by the arrows are often associated with which of the following conditions? | View Page |
| Approximately 80 - 90% of the neutrophils on the peripheral blood smear of a young man are similar to those in the image. This peripheral smear most likely represents which condition? | View Page |
| The upper image of a peripheral blood smear reveals RBC rouleaux formation. Several blood cells that are similar in appearance to the one indicated by the arrow in the bottom image are also seen on the smear. Which of the following conditions is associated with both of these findings? | View Page |
| Normal Bone Marrow Illustrated in the photograph is a normal bone marrow smear stained with Wright/Giemsa stain. Note the evenly distributed cells with normal maturation in both the myeloid and erythroid maturation sequences.An estimation of the percentage composition of cells can be made by experienced observers from scanning of multiple fields. In some instances a detailed differential count of 300 or more cells must be made.In normal bone marrows, the myeloid to erythroid ratio (M:E ratio)ranges from 1.2:1 to 5:1.A ratio of less than 1.2:1 indicates depressed leukopoiesis or erythroid hyperplasia. Ratios of 6:1 or greater usually indicates infection, erythroid hypoplasia, or chronic myelogenous leukemia.An assessment of the overall cellularity is also useful. In general, cellularity of less than 25% indicates hypoplasia; greater than 75% indicates hyperplasia. | View Page |
| The upper photograph of this bone marrow section also reveals distinct hyperplasia with total replacement of the fat. The lower photograph is a Wright/Giemsa stain. Calculate the M:E ratio of the distribution of myeloid and erythroid cells in the lower photograph. The peripheral white blood count was 18,500/cumm. The most likely associated condition is: | View Page |
| Additional Comments The following pages in this presentation includes a series of white blood cell and platelet abnormalities (nonneoplastic) that may be identified in a peripheral blood smear. Many cases will simulate the practice of a peripheral smear review by a hematology technologist. He or she must assess what responses in patient care may be triggered by the clinician attempting to interpret the reported findings on a peripheral smear.Observations of white blood cell abnormalities in the peripheral blood smear should be reported in order to direct the physician to an immediate specific diagnosis, such as: Atypical lymphocytes, suggesting infectious mononucleosis rather than leukemia Toxic granules in neutrophils, as found in acute infections, or atypical granules suggesting a genetic disorder An unusual mix of cells, such as too many or too few neutrophils, monocytes, or other myeloid cells The presence of giant platelets, myelocytes, or other cells, suggesting a myelodysplastic syndromeIn summary, laboratory data should be presented to clinicians in a user-friendly fashion to promote effective decision making. | View Page |
| The peripheral blood smear shown in this image was held for review because of an increase in platelets. Conditions in which platelets are increased as noted in this image include: | View Page |
| Cells that appeared similar to those illustrated in this image were repeatedly encountered as the smear was reviewed. The peripheral white blood cell count was 51.0 X 109/L with an orderly maturation sequence. The comment "leukemoid reaction" may properly be appended to the report. | View Page |
| A peripheral blood smear with many myeloid cells was presented for morphology review (see image on the right). Toxic granulation and vacuoles in the neutrophil most likely represent which of the following conditions? | View Page |
| Toxic granulation noted in the neutrophils' cytoplasm reflects an increase in activity of which of the following?(Choose all that apply) | View Page |
| Atypical neutrophilic intra-cytoplasmic inclusions, as noted in the image, are present in a peripheral blood smear when one or more of the following underlying conditions are present: | View Page |
| Chediak-Higashi Anomaly In 1952 Dr. Chediak reported a childhood disorder in which abnormal cytoplasmic inclusions appeared in the neutrophils of four family members. In 1954 Higashi reported a similar abnormality in an 11-month old Japanese infant. These inclusions were identified as lysosomal in origin and found in this rare autosomal recessive disorder. Death in patients afflicted with this condition was usually related to recurrent infections or hemorrhage. Ocular and cutaneous albinism, increased susceptibility to pyogenic infections, abnormal granules in neutrophils, and a bleeding tendency are all prominent findings in Chediak-Higashi anomaly. Notice the striking neutrophilic inclusions which appear as coarse intra-cytoplasmic azurophilic granules(indicated by the arrows in the images on the right). These granules arise from dilated portions of the Golgi-endoplasmic reticulum lysosomal apparatus. | View Page |
| The pale-staining cytoplasmic bodies marked by the arrow in the image may be seen in each of the following conditions except: | View Page |
| Eosinophils The cytoplasm of eosinophils is evenly filled by numerous orange-red granules of uniform size. They do not overlie the nucleus. The eosinophil granules contain numerous enzymes including peroxidase, phospholipase D, catalase, acid phosphatase, and vitamin B12-binding proteins. The eosinophil's ability to kill bacteria is less than that of neutrophils. Their main purpose is to counteract parasitic infections and to participate in immune allergic reactions. They may also be increased in a variety of nonimmunologic inflammatory responses from bacteria and fungi causing chronic infections. A high percentages of eosinophils may be present in the peripheral blood smears of patients with a variety of non-neoplastic conditions including:Asthma Urticaria Loeffler syndrome Parasitic infections Malignancies, collagen vascular diseases, and myeloproliferative disorders may also may be settings for prominent eosinophils. | View Page |
| Which of the following conditions is NOT associated with an increase in the white blood cell shown in the image on the right? | View Page |
| Eosinophil description The cytoplasm of eosinophils is evenly filled by numerous orange-red granules of uniform size. They do not overlie the nucleus. The eosinophil granules contain numerous enzymes including peroxidase, phospholipase D, catalase, acid phosphatase, and vitamin B12-binding proteins. The eosinophil's ability to kill bacteria is less than that of neutrophils. Their main purpose is to counteract parasitic infections and to participate in immune allergic reactions. They may also be increased in a variety of nonimmunologic inflammatory responses from bacteria and fungi causing chronic infections. Malignancies, collagen vascular diseases, and myeloproliferative disorders may also may be settings for prominent eosinophils. | View Page |
| A peripheral blood smear is observed during a manual differental review. The patient is a 10 year-old boy with symptoms suggesting appendicitis and an appendectomy is being considered. The total WBC is 18.5 X 1000/uL, RBC's = 5.45 X 1M/uL, hemoglobin = 16.0 g/dL, hematocrit 48.2%.WBC differential:Segs = 53%, bands = 42% (two of which are shown in the image) monocytes = 2% lymphocytes= 2% These findings support the diagnosis of appendicitis. | View Page |
| The cell in this image is known as a MOTT cell. The condition in which these cells are associated is: | View Page |
| Approximately 10% of the circulating white cells were similar to the one seen in this image. The patient was 42 years old and visited his physician because of recent bruising. Note the absence of platelets on the smear. Possible associated conditions include: | View Page |
| Case History One A 14-year-old boy came to the physician's office with a sore throat that progressively worsened over a three-day period. His posterior pharynx was swollen, shiny and erythematous. The boy complained of pain on swallowing. His temperature was 98.5°F. A rapid direct streptococcal antigen test was positive. However, his symptoms did not subside over the next two days while on antibiotic therapy. Anorexia and nausea were persistent and compounded by a frontal headache. Cervical lymph nodes became noticeably enlarged. A complete blood count (CBC) was ordered. The results of the CBC were: WBC 11.9 x 109/L ( Reference interval= 3.8 - 9.8 x 109/L) with: 17% segmented neutrophils 5% band neutrophils 72% lymphocytes 6% monocytes All red cell findings were normal. The automated differential flagged for atypical cells, presumptively atypical lymphocytes. A peripheral blood smear was prepared. The image on the right is a representative field from the Wright-Giemsa stained smear (1000X magnification).A rapid qualitative test for infectious mononucleosis was positive. This is a case of group-A streptococcal infection superimposed on infectious mononucleosis. Symptoms subsided in three weeks following completion of the antibiotic therapy. | View Page |
| The large blue staining cells represented here in the photographs comprise 50% of the total white blood count. This picture is most consistent with which of the following conditions? (choose all that apply) | View Page |
| Case History Two An 80-year-old man was seen in the emergency room with sudden onset of right-side chest pain accentuated on inspiration. His cough was productive of yellow sputum, and he was short of breath. His temperature was 101.2°F. A chest X-ray revealed right middle lobe pneumonia. A complete blood count (CBC) was ordered. The results were as follows:CBC ParameterPatient ResultReference IntervalWBC33.0 x 109/L4.0 - 11.0 x 109/LRBC4.5 x 1012/L4.5 - 5.9 x 1012/LHemoglobin15.2 g/dL13.5 - 17.5 g/dLHematocrit44%41 - 53%Platelet200 x 109/L150 - 450 x 109/LSegmented neutrophil6540 - 80%Band neutrophil100 - 5%Lymphocyte 525 - 35%Eosinophil 30 - 5%Basophil 20 - 2%Monocyte252 - 10%A peripheral smear was reviewed based on the elevated WBC and increased monocyte count. A representative field from the Wright-Giemsa stained smear (1000X magnification) is shown on the right. The cells indicated by the blue arrows are atypical monocytes. They have abundant cytoplasm that is more blue than the typical gray-blue cytoplasm of normal monoctes. A few scattered vacuoles are also present. The atypical monocytes, in company with toxic neutrophils (indicated by the red arrow), appeared to be a response to infection. The patient had a past history of tuberculosis, which may account for the monocytosis. | View Page |
| Multiple Myeloma Plasma cells are uncommonly observed in the peripheral blood smear. They are normal constituents of lymph nodes, spleen, connective tissue and bone marrow. The presence of plasma cells in the peripheral blood is indicative of a large number of conditions, mostly related to infections , immune disorders, malignancies, toxic exposures, hypersensitivity reactions and their responses.Although mature plasma cells have a distinct appearance, they still may be confused morphologically with immature plasma cells and other cells with inclusions, reactive changes or nucleated red bloods cell with altered identities. In the image to the right, a plasma cell is present. The plasma cell has an eccentric immature nucleus with a muddy chromatin pattern. Note also clumping and stacking of the erythrocytes, typical of rouleaux formation, implicating an increase in plasma gamma globulin. Further studies are in order, including a bone marrow examination, where at least 30% of bone marrow cells should be variations of mature and immature plasma cells. Serum protein electrophoresis will reveal a monoclonal globulin spike, and light chains in excess of 1.0 gm/24 hours may be seen in the urine. The presence of lytic bone lesions is a convincing clinical clue. With these findings in combination, a diagnosis of myeloma can be made with assurance. | View Page |