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Alpha thalassemia intermedia (Hemoglobin H Disease) results from a deletion of three out of four alpha chain gene loci. Infants born with alpha thalassemia intermedia appear normal at birth but often develop anemia and splenomegaly by the end of their first year. Development and life expectancy are usually normal, but some affected individuals may require splenectomy and transfusion therapy.Hepatomegaly is not a common finding and there may be some association with mental retardation. Due to the hemolytic nature of this anemia, there may be an increase in respiratory infections, leg ulcers and gallstones. Skeletal changes are not commonly seen in hemoglobin H disease.Any ethnic group can have occurrences of hemoglobin H disease; but it is most often seen in Southeast Asia, the Middle East and the Mediterranean islands.

Thrombotic thrombocytopenic purpura (TTP) is an uncommon, but very serious consumptive platelet disorder. Its cause is unknown, but there are several possible precipitating factors including infection, carcinoma, and pregnancy. More women than men are affected by TTP. If left untreated, the mortality rate is in excess of 90% due to multiorgan failure. Hemolytic uremic syndrome (HUS) is also a platelet consumptive disorder. HUS is thought by some to be the same condition as TTP because both disorders have the same underlying pathology. However, HUS is more often associated with renal failure and TTP with neurological manifestations including visual impairment, weakness, headache, dizziness, disorientation. seizures, or coma. Microangiopathic hemolytic anemia, thrombocytopenia, and fever is associated with both TTP and HUS. The patient's condition can deteriorate rapidly while these symptoms are becoming evident. HUS is usually seen in children; it is the most common cause of acute renal failure in children. Patients may have bloody diarrhea and symptoms resembling colitis. Diarrhea-related HUS is usually associated with ingestion of undercooked beef contaminated with Ecoli O157:H7; it is the Shiga-like toxin from this serotype that causes the illness. Some patients may have long term kidney dysfunction as a result ofthis virulent infection. For patients who have experienced renal failure, dialysis may be required.

Acute ITP occurs most often in children who are between 1 and 7 years of age subsequent to a viral infection such as measles, rubella, Epstein-Barr, chicken pox or cytomegalovirus (CMV). The platelet count may drop below 20 x 109/L and the patient may experience excessive bruising, nose bleeds, and petechiae. Spontaneous remission usually occurs within 2 - 6 weeks of onset of acute ITP so that treatment is often not needed unless the platelet count drops below 10 x 109/L, a level at which there is a high risk of bleeding into the central nervous system. The usual course of action is to try to prevent trauma that could result in bleeding and then periodically check the platelet count until it returns to normal.

Children with beta thalassemia major, also called Cooley's anemia, usually develop clinical signs during their first year of life. They appear to be malnourished and may exhibit abdominal girth expansion. They show bone marrow expansion and skeletal deformations, which are a result of increased erythropoiesis due to low hemoglobin levels. A common finding is facial bone changes caused by this bone marrow expansion (sometimes referred to as Mongoloid facial features). Other clinical signs include frequent infections, hepatomegaly, splenomegaly, gall stones, leg ulcers, iron toxicity, and poor growth and sexual development. In addition, cardiac failure due to increased burden of the heart attempting to oxygenate the tissues, can lead to serious complications and death if the condition is not treated.In general, death usually occurs by the time these patients are in their early twenties unless treated with blood transfusions along with iron-chelating agents. If no chelating agent is used during treatment life will only be prolonged by about a decade.The different genotypes associated with beta thalassemia major are: B0/B0, B0/B+, or B+/B+.

A joint space has a membranous lining similar to the mesothelium found in the pleural and peritoneal cavities. The synovial lining cells, which make up this membrane, produce synovial fluid which lubricates the joints.In a normal joint there is a minimal total volume of fluid present. With joint trauma, such as infection or inflammation, the volume will be increased and synovial lining cells may be noted on the cytospin preparation in addition to the cell types normally present with infection, inflammation or hemorrhage. Synovial lining cells (see arrows) resemble miniature mesothelial cells or small macrophages. They can be found singly or in clumps and can have "foamy"-looking cytoplasm.

Ependymal cells (see arrow), are part of the lining of the brain and ventricles. They produce cerebrospinal fluid (CSF) and are involved in circulating the CSF over the brain, ventricles and the spinal cord. These cells are not a common finding in CSF cytospins but may be present in cases of hydrocephalus or chronic ventricular infection. They usually appear as very large multinucleated clumps.In the image on the right, notice how large this clump is in comparison to the red blood cells in the background.

Reactive mesothelial cells can be found when there is an infection or an inflammatory response present in a body cavity. This condition can be due to the presence of a bacterial, viral or fungal infection. It can also be the result of trauma or the presence of metastatic tumor.Reactive mesothelial cells tend to come in clusters and clumps and have a more washed out cytoplasm in body fluids. Notice in the image on the right, how indistinct the cytoplasmic borders are in this clump compared to normal mesothelial cells. The wide separation of the nuclei and the well defined nucleoli help to identify these as reactive mesothelial cells. However if there is any doubt, the smear should be sent for hematology or pathology review.Note: It is not uncommon for macrophages to be mixed into a reactive mesothelial clump.

Atherosclerosis is one of the leading causes of heart disease and its presence is an important risk factor for events leading to acute myocardial infarction (AMI). In the past, atherosclerosis was described as a cholesterol and lipid storage event. Now we know it is a chronic inflammatory disorder of the arterial vessels with lipid components. Atherosclerosis begins with damage to the cells that line the blood vessels. Some possible causes of this cell injury are bacterial infection, hyperlipidemia, hypertension, glycosylated products of diabetes, cytokines from adipose tissue, or exposure to toxins such as pollution and second-hand smoke. Monocytes and lymphocytes adhere to the injured site; macrophages enter and ingest proteins and, along with modified lipoproteins, create foam cells. An inflammatory milieu results as cytokines and other inflammatory molecules become involved; foam cells and white blood cells begin secreting cytokines and metalloproteinases. Myeloperoxidase is also released by degranulated white blood cells and macrophages. As inflammation and accumulation of these products continues, fatty dots and streaks are formed on the vessel lining and the formation of plaque begins. As the atherosclerotic process continues, involved cells proliferate forming a complex extracellular matrix and a fibrous cap. If development continues, possibly over decades, the plaque formations are distributed throughout various vessels, become calcified or collagenized and make the vessel walls rigid. The risk to patients with significant atherosclerosis is that eventually a narrowing of the artery (stenosis) can cause a reduction in oxygen delivery to tissues and plaque rupture can lead to an acute coronary event.

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.

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.

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.

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).

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.

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.

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.

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.

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%).

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.

The cerebrospinal fluid sample is obtained by a physician usually via lumbar puncture in the L3-L4 region. The opening pressure is first measured (nl 90-180 mm of water in lateral position) and if it is elevated greater than 200 mm, no more than 2 ml of CSF should be withdrawn. Sterile technique is always used to reduce the risk of infection. Care must be taken to avoid injury to neural tissue.

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.

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

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.

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.

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.

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

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.

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.

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.

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.

It is important to remember that the collection of a specimen by dermal puncture may involve the potential of exposure to bloodborne pathogens as well as other safety considerations for both the phlebotomist and the patient. Some important safety reminders are listed in the table below. Safety Reminder Reason Comment Gloves are always necessary Blood contaminates the skin during a capillary blood collection. Gloves protect the phlebotomist from potential exposure to bloodborne pathogens. Gloves must remain intact to be an effective barrier against exposure to potential pathogens. Wear additional PPE, such as lab coat or gown when appropriate or required. Safety goggles and surgical mask may be needed if there is a potential for splashes or sprays of blood. May be needed to protect the phlebotomist or may be required to protect the patient from potential infection in some cases. Safety goggles and mask should both be worn to adequately protect the eyes and mucous membranes from exposure to bloodborne pathogens if there is the potential for splashes or sprays of blood. Only have the equipment needed for this procedure at hand and additional equipment out of reach of the patient. Protects the patient from accidental injury Often, capillary procedures are performed on very young children who are curious and may grab something that could cause injury.

C-reactive protein (CRP) is a very sensitive acute phase reactant. Serum CRP levels increase following a variety of pro-inflammatory events such as infection, tissue necrosis, trauma, surgery and even malignancy. CRP levels can increase quickly and dramatically (often 100 fold) during inflammation. CRP can activate compliment, bind Fc receptors and can function as an opsonin, enhancing phagocytosis with certain infections. Measurement of CRP is not new, it has been on clinical laboratory testing menus for decades. However, a newer version of the CRP test is now in use to assess cardiovascular risk.High sensitivity-CRP (hs-CRP) assays have been developed that are more sensitive to the more subtle changes that can occur during chronic vascular inflammation. (Recall that atherosclerosis is an inflammatory process.) By measuring hsCRP we can get a glimpse at vascular function. CRP has been shown to be an independent risk factor for atherosclerotic disease and cardiac death. A 2002 prospective study of more than 27,000 patients showed that the CRP concentration is a stronger predictor of cardiovascular events than the LDL-cholesterol level.

Disseminated Intravascular Coagulation (DIC) is best described as a disorder of consumption, because clotting factors are depleted from the blood. Basically, clotting occurs randomly throughout the body, as opposed to just in the localized areas where vascular damage has occurred, consuming clotting factors and other components such as platelets in the process. Symptoms may range from a mild bleed, to severe, profuse bleeding, primarily dependant upon the availability of clotting factors. As more and more coagulation factors and components are consumed, the disorder progresses and symptoms worsen. Most heavily impacted are the levels of factors I, V, and VIII as well as the number of available platelets. Clinically, DIC is detected via an elevated (positive) FDP, positive D-dimer test, a prolonged PT and APTT, plus the manifestation of hemorrhagic episodes. DIC is diagnosed as two primary types, acute and chronic. Acute DIC manifests in a few hours or a few days, has a high mortality rate, and is seen in infections, obstetric complications, liver disease, and tissue injury. Chronic DIC is a secondary condition to some other disease state. Once you treat the primary disease, this type of DIC will go away. Treatment is often factor replacement therapy through the use of fresh frozen plasma and/or cryoprecipitate.

Sickle cell disease (SCD) manifests itself as a chronic hemolytic anemia. There is slowed growth and development in children with sickle cell anemia, who may present with dactylitis. In addition to the general symptoms of anemia (fatigue, weakness, pallor etc.) patients are prone to infection, cardiomegaly, usually due to iron deposits from frequent transfusions, and bone and organ infarcts. Male patients can experience priapism.Patients with SCD can experience vaso-occlusive, hemolytic, sequestration, and aplastic crises. The major symptom in SCD is pain. Pain is a warning sign that is related to vaso-occlusion and life-threatening complications.

The use of blood transfusions for stroke prevention in children with sickle cell disease (SCD) has become a standard of care. The goal is to keep the level of HbS under 30%. Transfusions are not normally needed for SCD unless patients develop a sudden worsening of anemia due to splenic sequestration or infection. Of concern is the occurance of iron overload. Iron chelators are helpful in the management of iron overload and include desferrioxamine and deferasirox.Transfusing phenotypically matched blood (especially C, E, and K) is highly recommended to prevent alloimmunization.

Serum ferritin (SF) level reflects the amount of storage iron in tissues. An elevated SF combined with elevated TS implies primary iron overload. Patients with hereditary hemochromatosis (HH) generally show increases in SF as adults, but a normal SF does not rule out the diagnosis of the disease. Children and premenopausal females with HFE mutations may have had inadequate time to develop iron overload, but may do so later in life.SF alone is inadequate as the sole screening test for HH because it lacks the necessary sensitivity and specificity. SF is frequently elevated in persons with inflammation, cancer, or infection. SF is often ordered along with the serum iron and TIBC when iron overload is suspected. SF is also important is assessing the efficacy of treatment of HH.Upper limits of reference intervals for SF are 200 ng/mL for premenopausal women and 300 ng/mL for men and postmenopausal women. 40 ng/mL is a typical lower limit for the reference interval.SF is measured in serum using immunochemical methods such as enzyme-linked immunosorbent assay (ELISA), immunoradiometric assay, immunochemiluminescent assay, and immunofluorometry. SF tests are available as automated assays and in kit form.(2)

Acquired Immunodeficiency syndrome (AIDS) is caused by the Human Immunodeficiency virus (HIV). When HIV enters a person's bloodstream, it attacks and kills the T-helper lymphocytes, which are essential to the body in fighting off infections. As these cells are lost, so is the body's ability to fight infection. Possibly months after the initial infecting episode, an infected person develops a mononucleosis-like illness lasting a week or two. A person may then be free of symptoms for years. But as the T-helper cells die, the person becomes vulnerable to many serious infections. The expected mortality is 100%, and there is no vaccine available to develop specific immunity.

Postexposure prophylaxis will be determined by exposure type and HIV infection status of source person. The postexposure prophylaxis determined by a qualified practitioner will balance risk of infection with toxicity of the medications.The postexposure prophylaxis must be started hours after the exposure.The postexposure prophylaxis should be re-evaluated 72 hours after exposure, particularly if additional information is available about source person.The postexposure prophylaxis may be necessary for 6 months.

The Florida Legislature finds that the public health will be served by facilitating informed, voluntary, and confidential use of tests designed to detect HIV infection.

At this time an enzyme called protease, using enzymes and proteins from preliminary protein molecules, forms capsomere segments which unite to form an icosahedral capsid.The capsid then changes into a bullet-shaped capsid and surrounds the viral RNA.Next some of the host cell's membrane joins with the viral glycoproteins gp120 and gp41 to form the spikes.Last, part of the host cell's surface membrane encloses the virus and becomes the envelope.

After penetration of the cell membrane by the gp41, the HIV capsid enters the cell's cytoplasm. Next, cellular enzymes strip away the capsid so that the HIV genome is released. Also stripped away are proteins p24 and p17. Protein 24 coats the HIV genome and protein 17 lines the inside of the capsid.

The DNA provirus continues to encode new HIV particles within the host cell. During this early stage the injured host cells, such as T-lymphocytes, are able to replace themselves, and the body remains able to launch a defensive response. Eventually, though, the number of viruses becomes overwhelming.

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.

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.

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.

Most likely means of dissemination: Solid or aerosolPrimary route of entry: Inhalation, absorption, or ingestionGeneral signs and symptoms: Sudden fever, chills, headaches, muscle aches, joint pain, dry cough, progressive weakness, and pneumonia.The disease is not transmissible through human contact.  When used as a WMD, infection would be acquired by handling infected material, eating or drinking contaminated food or water or by breathing in the bacterium.

Biological attacks involve bacteria, viruses or natural toxins. The effects of toxins can be immediate but for bacteria and viruses the effects may not be apparent for weeks. A bioterrorist may attack by infecting animals, contaminating food and water, spraying bacteria or viruses into the air. In infections such as smallpox and plague, once a few individuals are infected they can further spread the disease from person to person. An attack could also come from through a building's ventilation system, the mail, or even through exposure to an infected terrorist seeking to spread disease during an infectious stage.

Markely increased stainable iron is present in this biopsy. Iron stores may be increased in sideroblastic anemia, chronic infections, hemochromatosis, hemosiderosis due to numerous blood transfusions, chronic hepatitis, cirrhosis, and uremia.

Another rare but abnormal type of plasma cell is the Mott cell (morula cell). The compartments visible in the cytoplasm are immunoglobulins which have not been released. Mott cells may be seen in parasitic infections and malignant tumors.

Specialists in immunohematology perform all testing prior to blood transfusions and work to prevent transfusion infections. They also investigate any post-transfusion reactions. This specialty includes all lab procedures performed in the specialty of histocompatibility. Specialists in clinical chemistry analyze body fluids such as blood, urine, and spinal fluid to determine the chemical makeup, including the amount of carbohydrates, proteins, enzymes, and trace elements. The special covers urine microscopics and chemical evaluation of the liver, kidneys, lungs, heart, and other vital organ systems. This specialty also covers all testing performed in the specialties of radioassay and blood gas analysis. Specialists in blood banking can perform all immunohematology testing as well as testing from the specialties of clinical chemistry, hematology and serology/immunology that relates to donor blood. Clinical laboratory personnel who are licensed in the specialties of immunohematology, clinical chemistry, hematology, and serology / immunology may perform all tests in the blood banking specialty.

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.

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.

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.

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.

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.

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

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.

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.

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.

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

The second group of cells are the leukocytes, or white blood cells (WBC's). The leukocytes can be divided into two groups: mononuclear and granulocytic cells. Leukocytes are involved in the body's defense mechanisms against infection. The cell shown in the upper image is a mononuclear cell, in this case a monocyte. The cell shown in the lower image is a granulocyte, in this case a neutrophil. These cells will be presented in much more detail later.

Neutrophils have a relatively short life span. They are produced in the bone marrow, and when they reach the band or segmented stages are released into the peripheral blood. They remain there for approximately ten hours before randomly entering body tissues.Neutrophils in the blood stream can be divided into circulating granulocyte pool (CGP) and marginating granulocytic pool (MGP). The white blood cell count reflects the cells in the circulating pool. The cells in the marginating pool move quickly into the circulating pool when needed.During an infection the neutrophil concentration of the peripheral blood can increase almost immediately due to the shift of these cells from the marginating pool and release from the bone marrow storage pool, if needed. Neutrophils then migrate to areas of tissue damage or infection. Neutrophils do not reenter the blood stream from the tissues, thus end their life in the tissues either as a result of phagocytosis or senescence.

?Neutrophils have a relatively short life span.They are produced in the bone marrow, and when they reach the band or segmented stages are released into the peripheral blood.They remain there for approximately ten hours before randomly entering body tissues.Neutrophils in the blood stream can be divided into circulating granulocyte pool(CGP) and marginating granulocytic pool (MGP).The white blood cell count reflects the cells in the circulating pool.The cells in the marginating pool move quickly into the circulating pool when needed.During an infection the neutrophil concentration of the peripheral blood can increase almost immediately due to the shift of these cells from the marginating pool and release from the bone marrow storage pool, if needed.Neutrophils then migrate to areas of tissue damage or infection.Neutrophils do not reenter the blood stream from the tissues, thus end their life in the tissues either as a result of phagocytosis or senescence.

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.

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

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.

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.

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.

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).

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.

This program will provide you with basic information about bloodborne pathogens and vital precautions you must take to minimize your risk of workplace exposure to these infections.

Patients with Hepatitis B and other bloodborne infections can appear healthy, so you can't tell whose blood is infectious.So treat all:blood, body fluids, secretions (except sweat), excretions, non-intact skin, and mucous membranes as if they were infectious.That's what the term Standard Precautions means.

HIV is caused by the Human Immunodeficiency virus.When HIV enters a person's bloodstream, it attacks and kills the T-helper cells. These cells are part of a group of white blood cells known as lymphocytes, which are essential to the body in fighting off infections.As these cells are lost, so is the body's ability to fight infection.

The Hepatitis B Vaccine is one of the most important ways to prevent infection. About 90% of people who receive it get immunity.The present recombinant vaccine is made by genetically altered bakers yeast and contains no blood components. It is very safe.Side effects are minimal. Symptoms such as temporary soreness at the injection site, mild fever, or joint pain may occur but are rare.The procedure consists of three shots in the upper arm given over a six month period.The OSHA standard requires that employers provide the vaccine free of charge to you if your occupation puts you at risk. You may decline the vaccine; but you will be asked to sign a Declination Statement.

Infection is obviously a very serious indication, and effective antibiotic levels must be achieved as soon as possible. However, many antibiotics also have nephrotoxic or ototoxic effects; the concentrations of these antibiotics need to be monitored. Examples of antibiotics that are monitored by TDM include: Amikacin Gentamicin Tobramycin VancomycinAntibiotics such as ampicillin that are readily cleared and have a wide therapeutic window are not usually monitored by TDM.

At John's particular hospital, a stop sign on the door means not only means respiratory isolation, but also that special precautions for tuberculosis are in effect. At this point, John should obtain a a special particulate respirator mask which will be available outside the patient's room. He should put on the mask before entering the room, wash his hands before and after contact with the patient, and wear gloves and appropriate protective clothing during all contact with the patient. TB and most respiratory infections are transmitted via droplets in the air from respiratory secretions – thus the need for the masks.

Microlances (such as the Tenderfoot™ (ITC) or the QuikHeel™ (BD), shown here, are used to puncture the heel & collect capillary blood.These devices control the depth of incision, since going too deep into an infant's heel could injure the heel bone, and cause osteomyelitis (bone infection).

The most important bloodborne pathogens are: Hepatitis B and C & Human Immunodeficiency Virus (HIV). Hepatitis B is very infectious via the blood-borne route. 30% of needle-sticks from patients who are Hepatitis B will result in infection. Hepatitis C is much more common in the United States. HIV is rarely transmitted via needle-stick injury. Nevertheless, utmost care is needed, because of its very serious nature. HIV is not transmitted by casual contact.

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.

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

Cerebrospinal fluid (CSF) and all specimens collected from sterile sites should have a microscopic examination performed along with culture. Bacteria found in CSF, blood, tissue, and specimens from other sterile sites are always significant.CSF should be cytospun, if possible, to increase the chance of detecting a pathogen. The quantity of organisms seen and the amount and type of host cells, e.g., mononuclear or polymorphonuclear (PMN) white blood cells, is important to report. The presence of PMNs indicates bacterial infection. It is also important to determine and report whether the bacteria are found inside or outside of white blood cells.

Type of Cell Average Size Image Comments Epithelial cells 25 µm Appear pink/red on Gram stained smear. Larger than white blood cells. Have a single nucleus. They are an indication of a suboptimal or unacceptable specimen if present in large numbers in sputum specimens, tracheal or endotracheal aspirates, or in urine specimens. White blood cells 12 µm Appear pink/red on Gram stained smear. Most often, polymorphonuclear white blood cells (PMNs). White blood cells indicate inflammation and possible infection. The direct smear examination should focus within and around these cells. Hyphae/pseudohyphae Varies Appear blue on Gram stained smear. Hyphae are tubular filamentous fungal elements, which may show branching or intertwining. Pseudohyphae are multiple buds of yeast that do not detach, thereby forming chains. Yeast 7 µm Appear blue on Gram stained smear. Round to oval, often budding. About the same size as red blood cells. Generally much larger than bacteria. A few yeast may be present as normal flora in upper respiratory tract or genital tract. They may be significant if they predominate, or if budding yeast forms are seen. Red blood cells 7µm Appear red on Gram stained smear Not usually considered a significant finding.

Epithelial cells in large numbers within sputum smears means that the specimen is predominantly oral saliva, rather than true sputum from the lung. Epithelial cells in urine smears indicate that the sample has been contaminated by organisms found on the vulva or distal urethra. Bacteria found near or on epithelial cells are usually normal contaminating bacterial flora.White blood cells indicate inflammation and possible infection. The direct smear examination should focus within and around these cells.Red blood cells in a direct smear are not usually significant.Yeast may be present as normal flora in upper respiratory tract or genital tract. They may be significant if they predominate, or if budding yeast forms are seen.Hyphae are more likely to indicate the presence of fungal infection, but this determination requires correlation with clinical findings.Bacteria found in spinal fluid, blood, tissue and specimens from other sterile sites are always significant.Body fluids which are normally sterile must be examined carefully. If only one organism per oil immersion field is identified, then there are about 105 organisms per mL present in the sample! Bacteria observed in specimens from the throat, genital tract and other areas containing normal flora suggest infection only if their composition and type varies significantly from the norm.

PCR can be modified for the amplification of RNA with one additional step prior to the PCR process -- the addition of a retrovirus enzyme called reverse transcriptase. Reverse transcriptase is used to create a copy of DNA using the original RNA specimen. Though there are thermostable polymerases that have reverse transcriptase capabilities, they are not commonly used. Reverse transcriptase PCR (RT-PCR) is used for the detection of viruses, such as HIV, that have an RNA genome. RT-PCR methods provide early detection of infection, even before the formation of antibodies. Therefore, it is a particularly useful method for HIV and hepatitis C virus(HCV) detection in blood bank nucleic acid testing. In addition to testing for HIV and HCV, RT-PCR is also used for detection of Mycobacterium tuberculosis, cytomegalovirus (CMV), influenza A virus, and other microorganisms where the target is RNA.RT-PCR is commonly combined with real time PCR.

All needles are single use. That is, every needle is immediately discarded in a sharps container after one insertion. If you suspect that you inadvertently touched anything with the needle prior to inserting the needle into the patient's vein, the needle cannot be used; the safety device must be activated and the needle discarded.NEVER remove a needle from a patient and reinsert into another vein; this could put the patient at risk for infection.

Semen analysis can provide important information related to the function of the male reproductive system but, even when results are within normal limits, it does not ensure that a male is fertile. A normal semen analysis result does not mean that all causes of male infertility have been ruled out. One reason for this is that there can be considerable differences between one semen analysis result and another in a single individual. On the other hand, an abnormal result does not always mean that a couple cannot conceive. Men with suboptimal sperm counts have been known to father children. Also, infection, trauma, stress, febrile illness and medications can cause temporary subfertility. For all of these reasons multiple specimens are recommended for a complete analysis of the semen.

During a blood collection, bacteria that is present on the skin surface may adhere to the outside of the needle as it enters into the vein. This can allow bacteria to infect the puncture site. A serious infection of the blood (septicemia) or of the tissue (cellulitis) may result. To avoid an infection, it is imperative that the phlebotomist uses a technique that thoroughly cleanses the skin at the site prior to venipuncture.Once the phlebotomist locates a suitable vein for venipuncture, the site of the vein that will be punctured is cleaned with a pre-packaged wipe saturated with 70% isopropyl alcohol.The site is cleansed using a "target" motion beginning at the center of the site and moving outward in concentric circles applying enough pressure to move surface bacteria away from the puncture point. (This is demonstrated in the image on the right). It is not recommended to use a scrubbing back and forth motion to clean the site since you may drag bacteria from a dirty area back into the clean area. Allow alcohol to air dry for effective disinfection of the site. Never use non-sterile gauze to wipe dry the alcohol as this will contaminate the site.During the remainder of the procedure, the site must NOT be touched by anything that has not been cleaned in an identical manner. The phlebotomist should avoid retouching the site after cleaning. If it is absolutely necessary to re-palpate, the phlebotomist MUST clean the gloved finger in a manner identical to the above procedure. Make certain that no other piece of equipment touches the site. This includes ends of the tourniquet and gauze. If you suspect that your needle has touched the site before entry, dispose of the needle, re-clean the site and repeat the procedure using a new needle. If a patient complains that there is redness or pain at the puncture site, even hours or days after the procedure, immediately refer the patient to his/her physician for evaluation.

Blood is normally sterile. Any bacteria in the bloodstream is abnormal. A blood culture is collected to detect the presence of bacteria in the bloodstream. Blood is collected into appropriate media to allow for growth and identification of bacteria or other organisms that may be in the patient's bloodstream. A blood culture set usually consists of two bottles: an aerobic bottle and an anaerobic bottle. Blood cultures are usually ordered in multiple sets drawn from separate sites at different times. An improperly collected blood culture can have a serious impact on the care and treatment of a patient. If bacteria enters the culture vial from sources other than the blood, as a result of improper specimen collection, a patient may needlessly be treated for an infection that is not present. On the other hand, some collection errors may cause negative culture results when the patient actually has bacteria in his/her blood. A false-negative culture result could be a life-threatening error.

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

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.

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.••

•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

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.

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.

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.

Large clumps of white cells, such as the ones shown in the slide, are typically found in chronic infection. The clumping is due to increased mucus in the urine.

Parasites which may be found in urinary sediments include Trichomonas vaginalis, Enterobius vermicularis and Schistosoma haematobium. It is also important to note that parasites and parasitic ova may be seen in urine sediments as a result of fecal or vaginal contamination. This slide shows examples of Trichomonas vaginalis. In the female, Trichomonas is usually found as a contaminant from vaginal infection and is often accompanied by an increase in the number of white cells. Trichomonas is highly motile, measuring 5 - 15 microns with a characteristic pear shape. It has multiple anterior flagella and the nucleus is often apparent.

Transfusion-associated acute lung injury (TRALI) is a complication of blood transfusion that results in shortness of breath due to pulmonary edema, fever, and hypotension. The pulmonary edema is noncardiogenic which means it does not originate from the heart. TRALI is a severely life-threatening adverse reaction. Symptoms manifest within 6 hours of transfusion. Products typically implicated in TRALI are Whole Blood, Red Blood Cells, Fresh Frozen Plasma, Cryoprecipitate, and Platelets, with Fresh Frozen Plasma being the most often implicated product. In combined fiscal years 2005 through 2009, transfusion-related acute lung injury (TRALI) caused the higest number of reported fatalities (48%), followed by hemolytic transfusion reactions (26%) due to non-ABO (16%) and ABO (10%) incompatibilities. Complications of microbial infection, transfusion-associated circulatory overload (TACO), and anaphylactic reactions each accounted for a smaller number of reported fatalities. TRALI has accounted for the highest number of reported transfusion-related fatalities throughout the first decade of 2000.Cases occur in all age groups and genders. Most patients that develop TRALI have no history of adverse reactions. TRALI is generally under-diagnosed and under-reported and the true incidence may be higher than stated estimates. Under-diagnosing is due to lack of recognition of the condition and that it can be easily confused with other diseases. Also, TRALI may be attributed to the underlying condition of the patient.Reference: U.S. Food and Drug Administration Website. Fatalities reported to FDA following blood collection and transfusion: Annual summary for fiscal year 2009. Available at: http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/TransfusionDonationFatalities/ucm204763.htm. Accessed April 26, 2011.

Measures taken to reduce bacterial contamination of blood components include donor screening, improved skin disinfection, diversion of the first aliquot of blood, and pretransfusion bacterial detection. Screening of donors is done by questioning them about fever occurrence and dental or medical procedures that occurred days before donation. Donors who develop symptoms of an infection may be asked to notify the blood bank. Complete skin disinfection is not possible because of organisms living in places that are inaccessible, such as sebaceous glands and hair follicles. Factors affecting skin disinfection are the type and concentration of antiseptic, use or single or multiple antiseptics, method and steps of application, and contact time. Studies have shown that a two-stage method using a sponge scrub and ampule with tincture of iodine is the most effective method. The AABB recommends an initial 30 second scrub with a 0.7% iodophor solution followed by the application of a 10% iodophor compound, which must be allowed to dry for 30 seconds. To avoid normal flora contamination, blood may be diverted into a satellite bag at the beginning of donation. These bags are developed so that backflow is prevented. Blood contained in the satellite bag is used for blood grouping and infectious disease testing. Blood diversion is not a mandatory practice in the United States. The AABB requires that the transfusion service have a method to detect bacteria in all platelet components. Culture-based methods are used at blood collecting facilities near the time of collection. Hospital-based transfusion services use other less costly non-culture based methods such as gram staining or pH and glucose analysis prior to releasing the product for transfusion. Recently, a qualitative immunoassay for the detection of bacteria in platelets has been developed. This test detects antigens on the cell walls of the bacteria. It has been documented to be more sensitive than other non-culture based methods.

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.

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

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.