| Review 1 Garbutt JM. Littenberg B. Evanoff BA. Sahm D. Mundy LM.
Enteric carriage of vancomycin-resistant Enterococcus faecium in patients tested for Clostridium difficile.
Infection Control & Hospital Epidemiology. 20(10):664-70, 1999OBJECTIVE: To identify independent risk factors for enteric carriage of vancomycin-resistant Enterococcus faecium (VREF) in hospitalized patients tested for Clostridium difficile toxin.PATIENTS: Convenience sample of 215 adult inpatients who had stool tested for C. difficile between January 29 and February 25, 1996.RESULTS: 41 (19%) of 215 patients had enteric carriage of VREF. Five independent risk factors for enteric VREF were identified: (1) history of prior C. difficile infection, (2) parenteral treatment with vancomycin for > or = 5 days, (3) treatment with antimicrobials effective against gram-negative organisms, (4) admission from another institution, and (5) age > 60 years. These risk factors for enteric VREF were independent of the patient's current C. difficile status.CONCLUSIONS: Antimicrobial exposures are the most important modifiable independent risk factors for enteric carriage of VREF in hospitalized patients tested for C. difficile. | View Page |
| Case History A 63 year old man was seen in the emergency room with the complaints of sudden onset of fever, chills, and abdominal pain, accompanied by mild diarrhea. The blood pressure was 140/84, the pulse rate 82/minute, and the body temperature 39.8C. A blood sample was drawn for a complete blood count, and a blood culture.A second blood culture was drawn from the opposite arm, with 10 ml of blood being placed into each an aerobic and an anaerobic bottle, following customary practice.The complete blood count revealed a hemoglobin of 15.8 mg/dl, a hematocrit of 45%, and a white blood count of 4.2/L. The neutrophils were 39%, lymphocytes 45%, monocytes 10%, eosinophils 4% and basophils 2%. The platelet count was 255/L. The patient was admitted to the hospital for further work-up and empiric antibiotic therapy.Within 24 hours after admission, the body temperature had decreased to 38.2C, although the mild diarrhea persisted.A stool toxin test for Clostridium difficile was negative and neither enteric pathogens nor Campylobacter species were recovered in stool culture after 24 hours incubation. Fecal neutrophils were not seen on direct examination.
The anaerobic blood culture became positive 36 hours after inoculation. | View Page |
| Gas gangrene may be seen in infections with all the following clostridia except: | View Page |
| The gram stain shown in the photograph was prepared from a positive anaerobic blood culture bottle after 36 hours incubation. Based on the morphology of the bacterial cells (some with spores--blue arrows), the most likely identification is: | View Page |
| Colony Morphology The growth observed on the anaerobic blood agar plate after 48 hours incubation (see upper photograph), revealed a spreading colony. The spreading nature of the colony is better observed in the close-in photograph (lower). No growth was observed on subcultures incubated aerobically indicating that this isolate is truly an anaerobe (although aerotolerance studies would be needed for confirmation). The spreading nature of the colony and the lack of hemolysis are highly suggestive of Clostridium septicum. However, biochemical confirmation is necessary. | View Page |
| Clostridium Quad Plate Key reactions for the identification of Clostridium septicum are shown in the two quadrant plates shown in the photograph.Included in the upper photograph are reactions for milk (casein) proteolysis (12 o'clock quadrant), glucose fermentation, DNAse hydrolysis, and starch hydrolysis respectively reading clockwise.The media in the quadrant plate shown in the lower photograph include gelatin hydrolysis (2 o'clock quadrant) and fermentation of each of mannitol, lactose, and rhamnose respectively, reading clockwise.Milk (casein) hydrolysis
Glucose fermentation
Key reactions for the identification in the upper plate include no proteolysis of milk, fermentation of glucose (yellow red color along the inoculation streak), positive DNAse (reddish clearing around the streak) and negative reaction for starch.
Key reactions in the lower plate include hydrolysis of gelatin, fermentation of lactose (yellow pigment), and negative reactions for mannitol and rhamnose (no pigment).Most strains of C. perfringens hydrolyze starch and produce proteolysins of milk, the key reactions that distinguish C. septicum (negative). Reactions to the other tests do not distinguish between the two. | View Page |
| Clostridium septicum RapID ANA The definitive identification of C. septicum can be made using a profile of biochemical reactions, as is contained in the RapID ANA strip (see photograph). The upper set of tubules are reactions before addition of reagents; the bottom set of reactions after reagents are added.The upper set of letter codes is used to read the reactions before addition of reagents; the lower set of labels indicate the tests to read following addition of reagents.Of all the reactions included, only ONPG and NAG in the upper set are positive.The biotype number derived from this profile of reactions, 014000 codes for Clostridium septicum, thus confirming the identification. | View Page |
| Review 1 Lorimer JW. Eidus LB.:
Invasive Clostridium septicum infection in association with colorectal carcinoma.
Canadian Journal of Surgery. 37:245-9, 1994The association between invasive Clostridium septicum infection and colorectal carcinoma is examined by the presentation of three cases and a review of the literature.In the first two cases the patients presented with nontraumatic metastatic clostridial gas gangrene.In the third case a patient with chemotherapy-induced myelosuppression from concomitant multiple myeloma had a necrotizing transmural infection of the right colon.The apparent portal of entry of Clostridium septicum was an occult carcinoma of the ascending colon. The increasing evidence for a strong link between this organism and some cases of neutropenic enterocolitis is reviewed. | View Page |
| Review 2 Citron DM. Appelbaum PC.:
How far should a clinical laboratory go in identifying anaerobic isolates, and who should pay?
Clinical Infectious Diseases. 16 Suppl 4:S435-8, 1993Identification of anaerobic bacteria in specimens from sites of infection due to mixed organisms can be time-consuming and expensive. Laboratories should limit anaerobic workups by testing only those specimens that have been properly collected and transported to the laboratory.Use of selective and differential media for initial processing can provide rapid and relevant information to the clinician. Anaerobes isolated from normally sterile sites and sites of serious infection should always be completely identified. Group-or genus-level identifications may suffice in other instances.The Bacteroides fragilis group of organisms should always be identified because of their virulence and resistance to many antimicrobial agents.Some of the other organisms that warrant identification include Clostridium septicum (associated with gastrointestinal malignancy); Clostridium ramosum, Clostridium innocuum, and Clostridium clostridioforme (which are resistant to antibiotics); Clostridium perfringens (a cause of myonecrosis and gas gangrene,potentially serious infection); anaerobic cocci (which may be resistant to metronidazole and clindamycin); and fusobacteria (which may be virulent and resistant to clindamycin and penicillin). | View Page |
| Review 3 Kornbluth AA. Danzig JB. Bernstein LH.:
Clostridium septicum infection and associated malignancy. Report of 2 cases and review of the literature.
Medicine. 68(1):30-7, 1989We report 2 patients with myonecrosis due to Clostridium septicum and associated colon carcinoma and have reviewed the English language literature for all reported cases of atraumatic C. septicum infection. A total of 162 cases of C. septicum infection have been reported.Eighty-one percent of these patients had an associated malignancy. Thirty-four percent of all patients had associated colon carcinoma, while 40% had a hematologic malignancy. Thirty-seven percent of reported patients had an occult malignancy at the time of their infection with C. septicum. In many patients, the portal of entry was found in the large intestine.In a particularly lethal form (79% mortality) of C. septicum infection, known as "distant myonecrosis," infection metastatic from the initial site of infection causes severe myonecrosis, gangrene, and often death within hours of clinical detection. Overall, survival of patients with C. septicum infection is only 35%.Review of all cases of C. septicum infection suggests several conclusions. 1) Patients with malignancy, particularly colonic or hematologic, and patients with cyclic neutropenia who develop signs and symptoms of sepsis, especially with associated findings of abdominal pain or pain in an extremity, should be treated for possible clostridial infection. 2) C. septicum infection does not appear to be a result of a single specific defect in either humoral or cell-mediated immunity. Rather, it may occur in patients who are granulocytopenic and therefore prone to an enterocolitis. 3) Patients in whom an infection with C. septicum is found must undergo a vigorous search for malignancy following ac | View Page |
| Match the species of anaerobes and frequently associated conditions. | View Page |
| Each of the following statements is true concerning Clostridium septicum infections except: | View Page |
| A Brown and Brenn gram stain was performed on one of the tissue biopsy specimens. Organisms were seen as shown in the photograph. Based on the history and the appearance of the bacteria, the most likely identification is: | View Page |