title: Genetic relatedness between Japanese and European isolates of Clostridium difficile originating from piglets and their risk associated with human health.
abstract: Clostridium difficile colonization in pig intestine has been a public health concern. We analyzed C. difficile prevalence among piglets in Japan to clarify their origin and extent of the associated risk by using molecular and microbiological methods for both swine and human clinical isolates and foreign isolates. C. difficile was isolated from 120 neonatal piglet fecal samples. Toxin gene profile, antimicrobial susceptibilities, PCR ribotype, and multiple-locus variable-number tandem-repeat analysis (MLVA) type of swine isolates were determined and compared with those of human clinical and foreign isolates. One-hundred C. difficile strains were isolated from 69 (57.5%) samples, and 61 isolates (61%) were toxin gene-positive. Some isolates were resistant to antimicrobials, contributing to antibiotic-associated diarrhea by C. difficile. These results suggest that C. difficile, prevalent among Japanese pigs, is a potential risk for antibiotic-associated diarrhea. Furthermore, PCR ribotype 078 (12 isolates), which has been linked to multiple outbreaks worldwide, was the third-most frequently isolated of the 14 PCR ribotypes identified. Moreover, MLVA revealed that all 12 PCR ribotype 078 isolates were genetically related to European PCR ribotype 078 strains found in both humans and pigs. To date, in Japan, many breeding pigs have been imported from European countries. The genetic relatedness of C. difficile isolates of Japanese swine origin to those of European origin suggests that they were introduced into Japan via imported pigs.
authors.affiliation: Laboratory of Food Microbiology and Food Safety, Department of Health and Environmental Sciences, School of Veterinary Medicine, Rakuno Gakuen University Hokkaido, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Usui
authors.affiliation: Laboratory of Food Microbiology and Food Safety, Department of Health and Environmental Sciences, School of Veterinary Medicine, Rakuno Gakuen University Hokkaido, Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Nanbu
authors.affiliation: Miyarisan Pharmaceutical Co., Ltd. Tokyo, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Oka
authors.affiliation: Miyarisan Pharmaceutical Co., Ltd. Tokyo, Japan ; Department of Infectious Diseases, Kyorin University School of Medicine Tokyo, Japan.
authors.forename: Motomichi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Infectious Diseases, Tokyo Metropolitan Geriatric Hospital Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Inamatsu
authors.affiliation: The United Graduate School of Veterinary Sciences, Gifu University Gifu, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Asai
authors.affiliation: Department of Infectious Diseases, Kyorin University School of Medicine Tokyo, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kamiya
authors.affiliation: Laboratory of Food Microbiology and Food Safety, Department of Health and Environmental Sciences, School of Veterinary Medicine, Rakuno Gakuen University Hokkaido, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tamura
keywords: Clostridium difficile; MLVA; PCR ribotype 078; antimicrobial resistance; piglets