1379. Clinical and molecular characterization of Clostridium difficile isolated in a university hospital in Japan: a retrospective study
Session: Poster Abstract Session: Clostridium difficile
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C

The increase of Clostridium difficileinfection (CDI) is becoming a serious problem in the world. Especially, emergence and spreading of hypervilurent strain, like ribotype 027, was associated with hospital/community outbreak of and high mortality in CDI. Hypervirulent strain was shown to produce the third toxin, named binary toxin, in addition to toxin A and B. Exact incidence of binary toxin-producers in Japan is still unknown, although there were several cases of CDI with binary toxin producers. The aim of this study is to identify and analyze clinical and molecular characteristics of CDI in Japan.

Methods: In 2010, 1050 stool samples from inpatients with unexplained fever and concurrent gastrointestinal symptoms were examined for culture of C. difficile. Isolated C. difficile were examined in toxin genes (tcdA, tcdB, cdtA and cdtB) by PCR, sequence analysis of tcdC, and ribotyping, as previously described. A retrospective chart review of patients with CDI by binary toxin producers was performed. Antibiotic susceptibility testing of vancomycin, metronidazole and moxifloxacin for isolated C. difficile was examined by E-test.

Results: Total 187 C. difficile strains were isolated. Among these strains, toxin A and B positive, toxin B positive and binary toxin positive strains were 122 (65.2%), 3 (1.6%) and 12 strains (6.4%), respectively. PCR ribotype 027 strains were not identified. Of 12 patients with CDI by binary toxin producer, 3 cases were defined to the definite CDI by CDC criteria, and 2 patients died from CDI-related causes. All strains examined were sensitive to metronidazole and vancomycin. Only one isolate was resistant to moxifloxacin (MIC>32 μg/ml). No deletion mutants at position 117 of tcdC gene was found. Two isolates of 18bp deletion, 5 of 39bp deletion and a nonsense mutation (C184T) were detected. Interestingly, the tcdC genotypes correlated with PCR ribotyping.

Conclusion: These data demonstrated comparably high incidence of toxin producing C. difficile in Japan. Although PCR ribotype 27 was not detected, it may be important that 6.4% of isolates were binary toxin producers. Further epidemiological, clinical and molecular survey of C. difficile and CDI were warranted.

Nobuaki Mori, M.D., Ph.D.1,2, Sadako Yoshizawa, MD, PhD2, Tomoo Saga, M.D., Ph.D2, Yoshikazu Ishii, Ph.D.2 and Kazuhiro Tateda, M.D, Ph.D2, (1)General Internal Medicine, National Hospital Organization Tokyo Medical Center, Tokyo, Japan, (2)Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Tokyo, Japan


N. Mori, None

S. Yoshizawa, None

T. Saga, None

Y. Ishii, None

K. Tateda, None

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