Evaluation of Quantitative culture of Clostridium difficile From Fecal Specimens for the Diagnosis of C. difficile-associated Disease / 대한임상미생물학회지

ABSTRACT

BACKGROUND: C. difficile-associated diarrhea (CDAD), the most frequently identified cause of nosocomial diarrhea, results from the overgrowth of cytotoxin (toxin B)-producing strains. The aim of this study was to evaluate the quantitative culture of Clostridium difficile to improve the laboratory diagnosis of CDAD. METHODS: The quantitative culture and cytotoxin gene results were evaluated based on the findings of colonoscopy and/or histology of the biopsy specimens. RESULTS: Among the 402 specimens with cytotoxin-positive isolates, 301 (74.9%) contained > or =106 CFU/mL of C. difficile. Nine (60%) of the 15 pseudomembranous colitis patients yielded > or =106 CFU/mL of toxigenic isolate. The proportion of cytotoxin gene-positive isolates was higher in the specimens with > or =106 CFU/mL of C. difficile than in those with 102-<103 CFU/mL (86.5% vs. 66.7%). CONCLUSIONS: Quantitative culture may aid in the interpretation of toxigenic C. difficile culture results, and reduce false positivity, thus avoiding unnecessary treatment.