Korean J Lab Med.  2010 Oct;30(5):491-497. 10.3343/kjlm.2010.30.5.491.

Investigation of Toxin Gene Diversity, Molecular Epidemiology, and Antimicrobial Resistance of Clostridium difficile Isolated from 12 Hospitals in South Korea

• Kim H
• Jeong SH
• Roh KH
• Hong SG
• Kim JW
• Shin MG
• Kim MN
• Shin HB
• Uh Y
• Lee H
• Lee K

• KMID: 1022040
• DOI: http://doi.org/10.3343/kjlm.2010.30.5.491

Abstract

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.

Keyword

Clostridium difficile; toxin A; toxin B; Ribotyping; Drug Resistance; Epidemiology

MeSH Terms

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

Figure

• 

  Fig. 1. PCR ribotype patterns of the Clostridium difficile isolates representing PCR ribotypes AB24, C11, C5, C2, AB14, AB23, and aB (Lane 1 to 7, respectively). Lane L refers to 100 bp ladder. Banding patterns of the C5, C2, and aB ribotypes were identical to the pattern of C. difficile ribotype 027, 078, and 017 strains.

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