[Recent epidemiology of Clostridium difficile infection in Japan]

Clostridium difficile (C. difficile) is a major pathogen for diarrhea in hospitalized patients and because of outbreak of highly virulent strain in EU and US, increased length of hospital stay and increased numbers of severe patients and deaths have become major challenges. In recent years, transmissions through community-acquired or food-borne infections are reported. National surveillance has been already performed overseas. Guidelines for preventing C. difficile infection (CDI) is available, and education activities are promoted for preventing the infection spread. Meanwhile, in Japan, medical hospitals are reporting individual CDI incidence, however, a large-scale research has not been conducted up to the present date and therefore the entire status of CDI including infection of the highly virulent strain has yet to be revealed. This time, we performed a questionnaire-based survey at 2,537 hospitals nationwide between April 15, 2013 and May 31, 2013 to investigate CDI incidence, diagnosis and treatment. Valid responses were obtained from 321 hospitals. Regarding the annual number of CDI patients at all the hospitals, the highest group of hospitals responding "1 to 5 patients a year" was 17.8%, and the second highest group of hospitals responding "no patients a year" was 13.1%. In contrast, there was a group of hospitals with "more than 101 patients a year", which was 3.1%. This indicates that there was the difference in the CDI incidences among hospitals. According to the questionnaire results, a highest group of hospitals responding "0-20%" for CDI patients with serious complication such as toxic megacolon, gastrointestinal perforation, ileus paralytic, bacteremia, sepsis, crohn's disease, and ulcerative colitis was 62.6%, and for CDI patients with recurrence more than one, a group of hospitals answering "0 to 20%" was 56.4%, which was the highest. This suggested that there was only a small number of serious CDI patients and recurrence CDI patients in Japan. For rapid toxin detection kit used in CDI diagnosis, a group of hospitals using "C. DIFF QUIK CHEK COMPLETE" was over 40%, which showed that the kit was a major product used in Japan. And a group of institutions responding that they will start antibacterial medication such as vancomycin (VCM) and metronidazole (MNZ) as soon as after rapid diagnostic test, etc. showing positive results was over 70%. As for CDI treatment, a highest group of hospitals answering that VCM is administered orally at a dose of "0.5 g four times daily" was 42.1%, and a group of hospitals responding "10 to 14 days" for administration period was 44.2%, which was the highest. A highest group of hospitals answering that MNZ is administered orally at a dose of "250 mg four times daily" was 38.3%, and a group of hospitals responding "10 to 14 days" for administration period was 46.4%, which was the highest. Apart from VCM and MNZ, probiotics are also used for CDI treatment, "butyric acid bacterium" accounted for 40.8% in the probiotics group, which was the highest, followed by "bifidobacteria" 37.7% and "resistant lactic acid bacterium" 25.6%. To prevent the spread of CDI, 47.7% of the hospitals responded that the patients are "isolated", while 25.6% answered the patients are "sometimes isolated", which means that more than 70% of patients are "isolated or sometimes isolated". As to what type of antiseptic drug is used for sterilizing hospital, 68.2% of the hospitals answered that they are using "sodium hypochlorite 1,000 ppm". The survey more than 300 hospitals have revealed not only the CDI incidences, timing of toxin test, and part of the actual therapeutic strategy at medical institutions in Japan but also the difference in the CDI incidences and therapeutic strategy among hospitals. In the future, epidemiological data on epidemic strain will be accumulated more in Japan as are done overseas, and guidelines for CDI diagnosis and treatment will need to be formulated.