Clostridium Difficile - Stool Culture Diagnosis

10/14/2002

Question: Is there evidence to support repeat testing for Clostridia difficile?

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Unique Identifier:8712901

Authors: Valenstein P. Pfaller M. Yungbluth M.

Institution: Department of Pathology, Catherine McAuley Health Systems, Ann Arbor MI 48106, USA.

Title: The use and abuse of routine stool microbiology: a College of American Pathologists Q-probes study of 601 institutions.

Source: Archives of Pathology & Laboratory Medicine. 120(2):206-11, 1996 Feb.

Abstract: OBJECTIVE: To examine the efficiency with which physicians use routine stool microbiology tests. DESIGN: Questionnaire and structured review of 100 consecutive stool bacteriology and parasitology examinations at each participating institution. SETTING: Six hundred one institutions enrolled in the College of American Pathologists Q-probes Program. RESULTS: Of 59500 bacteriology specimens, 3808 (6.4%) contained a pathogen. The vast majority (99%) of bacterial pathogens were detected in either the first or second specimen submitted. Almost 40% of inpatient specimens were collected after the third day of hospitalization, but only 0.6% of these specimens were positive for enteric pathogens that had not been previously recovered. More than half of the laboratories reported having no limits on the number of bacteriology specimens per patient that could be submitted for testing, and fewer than 8% of laboratories rejected specimens from inpatients after a certain number of days in the hospital. The frequency with which laboratories performed tests for Clostridium difficile varied widely. Of 58500 parasitology specimens, 1463 (2.5%) contained a pathogen; 97.6% of pathogens were detected by the second stool specimen, and 99.8% were detected by the third specimen. Only 0.7% of specimens from inpatients hospitalized more than 4 days contained a new pathogen. CONCLUSIONS: We recommend that no more than two bacteriology specimens and no more that two or three parasitology specimens be processed per patient without consultation. Standard stool examination for a bacterial pathogens has a low yield and should not be performed after 3 days of hospitalization. Likewise, parasitology examinations should not be performed after 4 days of hospitalization.

 Link Directly to Fulltext article in Ovid

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Unique Identifier:7486465

Authors: Manabe YC. Vinetz JM. Moore RD. Merz C. Charache P. Bartlett JG.

Institution: Johns Hopkins School of Medicine, Division of Infectious Diseases, Baltimore, MD 21205, USA.

Title: Clostridium difficile colitis: an efficient clinical approach to diagnosis. [see comments.].

Source: Annals of Internal Medicine. 123(11):835-40, 1995 Dec 1.

Abstract: OBJECTIVE: To define clinical and laboratory variables that suggest the presence of Clostridium difficile colitis and to establish the number of stool specimens needed to reasonably exclude the diagnosis of C. difficile colitis. DESIGN: Prospective study of consecutive inpatients whose stool specimens were sent to be evaluated for the presence of C. difficile toxin. SETTING: University teaching hospital. PATIENTS: 268 hospital inpatients in medical, surgical, and gynecology units. MEASUREMENTS: Structured history and physical examination; detection of C. difficile toxin by cytotoxin tissue-culture assay with anti-C. difficile antiserum neutralization and by enzyme-linked immunoassay (EIA) for C. difficile toxins A and B; and detection of fecal leukocytes by microscopic examination and by latex agglutination lactoferrin assay. RESULTS: 43 of 268 consecutive inpatients were positive for C. difficile toxin by EIA or tissue-culture assay. Although toxin was detected by EIA alone in 39 of the 43 patients, it was detected in an additional 4 patients (10%) by tissue-culture assay alone. Univariate and multivariate logistic regression analysis showed that the following clinical and laboratory features were associated with C. difficile toxin positivity: the onset of diarrhea 6 or more days after the administration of antibiotics (odds ratio, 1.38 [95% CI, 1.10 to 3.79]); hospital stay longer than 15 days (odds ratio, 1.33 [CI, 1.09 to 3.95]); the presence of fecal leukocytes determined by microscopy (odds ratio, 2.39 [CI, 1.05 to 5.42]) or lactoferrin assay (odds ratio, 3.74 [CI, 1.80 to 7.76]); the presence of semiformed (as opposed to watery) stools (odds ratio, 2.33 [CI, 1.10 to 4.90]); and cephalosporin use (odds ratio, 2.36 [CI, 1.10 to 5.09]). Toxin-positive patients were no more likely than controls to have had fever, abdominal pain or cramps, leukocytosis, green-colored diarrhea, or blood in the stool or to have received clindamycin or penicillin derivatives. Of the 43 patients with C. difficile toxin, 34 (79%) had positive results for the toxin on the first stool specimen, 5 (cumulative, 91%) had positive results on the second specimen, and 4 had positive results on the third specimen. Overall, the negative predictive value of the first stool specimen was 97%. All patients who had two or more clinical or laboratory predictors were diagnosed with C. difficile disease when either the first or the second stool specimen was positive for toxin. CONCLUSIONS: Clinicians at the bedside can use readily available clinical and laboratory information to decide which patients are likely to have C. difficile disease and when it is appropriate and useful to order specific diagnostic tests for C. difficile toxin. Such data are also useful in determining the number of stool samples that reasonably excludes the diagnosis of C. difficile colitis. CAS Registry/EC Number 0 (Bacterial Toxins).