BACKGROUND: Clostridium difficile is a major cause of antibiotic-associated diarrhea. The objective of this study was to characterize clinical isolates of C. difficile obtained from various regions in Korea with regard to their toxin status, molecular type, and antimicrobial susceptibility. METHODS: We analyzed a total of 408 C. difficile isolates obtained between 2006 and 2008 from 408 patients with diarrhea in 12 South Korean teaching hospitals. C. difficile toxin genes tcdA, tcdB, cdtA, and cdtB were detected by PCR. Molecular genotyping was performed by PCR ribotyping. Antimicrobial susceptibilities of the 120 C. difficile isolates were assessed by agar dilution methods. RESULTS: Among 337 toxigenic isolates, 105 were toxin A-negative and toxin B-positive (A-B+) and 29 were binary toxin-producing strains. PCR ribotyping showed 50 different ribotype patterns. The 5 most frequently occurring ribotypes comprised 62.0% of all identified ribotypes. No isolate was susceptible to cefoxitin, and all except 1 were susceptible to piperacillin and piperacillin-tazobactam. The resistance rates of isolates to imipenem, cefotetan, moxifloxacin, ampicillin, and clindamycin were 25%, 34%, 42%, 51%, and 60%, respectively. The isolates showed no resistance to metronidazole or vancomycin. CONCLUSIONS: This is the first nationwide study on the toxin status, including PCR ribotyping and antimicrobial resistance, of C. difficile isolates in Korea. The prevalence of A-B+ strains was 25.7%, much higher than that reported from other countries. Binary toxin-producing strains accounted for 7.1% of all strains, which was not rare in Korea. The most prevalent ribotype was ribotype 017, and all A-B+ strains showed this pattern. We did not isolate strains with decreased susceptibility to metronidazole or vancomycin.
Clostridium Infections/microbiology ; Clostridium difficile/classification/*genetics/isolation & purification ; Diarrhea/microbiology ; *Drug Resistance, Bacterial ; Enterotoxins/*genetics ; Genetic Variation ; Genotype ; Hospitals, University ; Humans ; Microbial Sensitivity Tests ; Republic of Korea ; Ribotyping

Clostridium difficile (C. difficile) is a common causative agent of pseudomembranous colitis (PMC). C. difficile-associated diarrhea (CDAD) ranges from mild diarrhea to life threatening PMC. Recently, a highly virulent strain of C. difficile polymerase chain reaction ribotype 027 was found in North America, Europe, and Japan. A 52-yr-old woman with anti-tuberculosis medication and neurogenic bladder due to traffic accident experienced five episodes of C. difficile PMC after taking antibiotics for pneumonia along with septic shock and acute renal failure. She was readmitted to the intensive care unit and treated with oral vancomycin with refractory of oral metronidazole, inotropics and probiotics for over 60 days. C. difficile isolated both at the first and the last admission was identified as C. difficile ribotype 027 by ribotyping, toxinotyping, and tcdC gene sequencing, which turned out the same pathogen as the epidemic hypervirulent B1/NAP1 strain. This is the first case of C. difficile PCR ribotype 027 in Korea. After discharge, she was maintained on probiotics and rifaximin for 3 weeks. She had no relapse for 6 months.
Accidents, Traffic ; Antitubercular Agents/therapeutic use ; Base Sequence ; Clostridium difficile/*classification/genetics/isolation & purification ; Enterocolitis, Pseudomembranous/*diagnosis/drug therapy/*microbiology ; Female ; Humans ; Kidney Failure, Acute/diagnosis ; Korea ; Middle Aged ; Molecular Sequence Data ; Polymerase Chain Reaction ; Ribotyping ; Shock, Septic/diagnosis