コモリ　コウジ   Komori Kouji   小森　光二    所属   東邦大学  医学部 医学科    職種   助教
論文種別	原著
言語種別	英語
査読の有無	査読なし
表題	One Health genomic insights into environmental and animal reservoirs of community-associated Clostridioides difficile in Japan.
掲載誌名	正式名：Applied and environmental microbiology
掲載区分	国外
巻・号・頁	92(6),pp.e0039726
著者・共著者	Sadako Yoshizawa,Kohji Komori,Kotaro Aoki,Tomoka Sawa,Yoshimasa Sasaki,Yasuhisa Kurosaki,Yoshiteru Murata,Tomoko Kasai,Nobuaki Mori,Tetsuo Asai,Yoshikazu Ishii,Kazuhiro Tateda
発行年月	2026/06/17
概要	Clostridioides difficile is a well-recognized cause of antibiotic-associated colitis. The highly pathogenic PCR ribotype(RT)027/sequence type(ST)1 strain has been prevalent since 2002, particularly in Europe and the United States, whereas strains detected in Japan primarily comprise RT018/ST17, RT369/ST81, and RT002/ST8. Community-associated C. difficile infection (CA-CDI) has increased in recent years, and an association with livestock, food, and companion animals has been suggested. This study investigated the molecular epidemiology of C. difficile in Japan, focusing on isolates from diarrheal outpatients in comparison with animal and environmental sources. A total of 401 samples were collected, including park soil and fecal samples from livestock, companion animals, wild animals, and outpatients. Overall, 63 strains were isolated. High isolation rates were observed in soil samples (19/37, 51%) and companion animals (19/64, 30%), of which 68% and 37% were toxigenic, respectively. Whole-genome sequencing revealed ST2 as the most common sequence type, followed by ST42 and ST15. No single sequence type predominated among isolates from diarrheal outpatients, and six patients met the epidemiological definition of CA-CDI. Core-genome single-nucleotide polymorphism (SNP) analysis identified close genetic relationships in two pairs of ST42 strains-one between a patient-derived isolate and park soil, and another between a canine-derived isolate and soil from a different park-using a hypothetical transmission-exclusion cutoff of <13 SNPs. These findings suggest the presence of shared environmental reservoirs linking humans, animals, and soil, rather than indicating the direction of transmission. The study highlights the importance of considering environmental reservoirs within a One Health framework for CA-CDI in Japan.IMPORTANCEClostridioides difficile infection (CDI) is a widely recognized cause of antibiotic-associated diarrhea, and reports of community-associated CDI (CA-CDI) have risen in recent years. Understanding how C. difficile circulates outside healthcare settings is, therefore, an important public health challenge. In this study, we analyzed C. difficile isolates from outpatients with diarrhea, companion animals, and environmental sources, including soil from public parks. The organism was frequently detected in soil and pets, and genomic analyses identified closely related strains across human, animal, and soil samples. Although these findings do not indicate transmission direction, they suggest that environmental reservoirs may contribute to the broader ecology of C. difficile in the community. Our results underscore the importance of a One Health perspective integrating human, animal, and environment together when studying CA-CDI and highlight the need for further research to better understand how C. difficile persists and spreads outside hospital settings.
DOI	10.1128/aem.00397-26
PMID	42113022