Annals of Clinical Microbiology (Ann Clin Microbiol) 2002 December Volume 5, Issue 2, pages 124-128.
Dongeun Yong, M.D.,* Hyuk Min Lee, M.D.,* Jong Ha Ryu, M.D.,* Kyung Ho Roh, M.D.,* Won Ho Kim, M.D.,**,*** Kyungwon Lee, M.D.,*,*** and Yunsop Chong, M.D.,.
Department of Laboratory Medicine, Research Institute of Bacterial Resistance,* Department of Internal Medicine,** and Brain Korea 21 Project for Medical Sciences,*** Yonsei University College of Medicine, Seoul, Korea
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 ≥106 CFU/mL of C. difficile. Nine (60%) of the 15 pseudomembranous colitis patients yielded ≥106 CFU/mL of toxigenic isolate. The proportion of cytotoxin gene-positive isolates was higher in the specimens with ≥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. (Korean J Clin Microbiol 2002;5:124-128)
Clostridium difficile, C. difficile-associated diarrhea, pseudomembranous colitis, quantitative culture, cytotoxin
