Yasugi Mayo, Hatoya Shingo, Motooka Daisuke, Kondo Daisuke, Akiyoshi Hideo, Horie Masayuki, Nakamura Shota, Shimada Terumasa
Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan; Asian Health Science Research Institute, Osaka Metropolitan University, Izumisano, Osaka, Japan; Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Izumisano, Osaka, Japan.
Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan.
Vet Microbiol. 2023 May;280:109695. doi: 10.1016/j.vetmic.2023.109695. Epub 2023 Feb 16.
The emergence of mcr plasmid-mediated colistin-resistant extended-spectrum β-lactamase (ESBL)-producing Enterobacterales among companion dogs and cats poses a risk of the animals acting as reservoirs for cross-species transmission. However, current knowledge of mcr-harboring ESBL-producing Enterobacterales in companion dogs and cats is still limited; thus, the genetic and phenotypic characteristics of the bacterial isolates and plasmids, in companion dogs and cats, remain to be elucidated. Here, we identified mcr gene-harboring ESBL-producing Escherichia coli isolates during whole-genome sequencing of ESBL-producing E. coli isolates from a dog and a cat in Osaka, Japan. Colistin-resistant MY732 isolate from a dog carried two plasmids: mcr-1.1-harboring IncI2 plasmid and bla-harboring IncFIB plasmid. Conjugation assays revealed that both plasmids can be co-transferred even though the IncFIB plasmid lacked a conjugal transfer gene cassette. The other isolate MY504 from a cat harbored two bla genes and mcr-9 on the identical IncHI2 plasmid. This isolate was not resistant to colistin, which is likely to be due to deletion of the regulatory two-component QseBC system associated with the mcr-9 expression. To the best of our knowledge, this is the first report of a colistin-resistant ESBL-producing E. coli isolate harboring mcr-1 from a companion dog in Japan. Given that the mcr gene-harboring IncI2 and IncHI2 plasmids in this study shared high homology with plasmids from human or animal-derived Enterobacterales, companion dogs and cats may act as important reservoirs for cross-species transmission of the mcr gene in the community, in Japan.
在伴侣犬猫中出现的携带mcr质粒介导的耐黏菌素超广谱β-内酰胺酶（ESBL）的肠杆菌科细菌，使这些动物有成为跨物种传播储存宿主的风险。然而，目前关于伴侣犬猫中携带mcr的产ESBL肠杆菌科细菌的知识仍然有限；因此，伴侣犬猫中细菌分离株和质粒的遗传及表型特征仍有待阐明。在此，我们在对日本大阪一只犬和一只猫的产ESBL大肠杆菌分离株进行全基因组测序时，鉴定出了携带mcr基因的产ESBL大肠杆菌分离株。来自一只犬的耐黏菌素MY732分离株携带两个质粒：携带mcr-1.1的IncI2质粒和携带bla的IncFIB质粒。接合试验表明，即使IncFIB质粒缺乏接合转移基因盒，这两个质粒也能共同转移。来自一只猫的另一个分离株MY504在同一IncHI2质粒上携带两个bla基因和mcr-9。该分离株对黏菌素不耐药，这可能是由于与mcr-9表达相关的双组分调控系统QseBC缺失所致。据我们所知，这是日本首次报道从伴侣犬中分离出携带mcr-1的耐黏菌素产ESBL大肠杆菌分离株。鉴于本研究中携带mcr基因的IncI2和IncHI2质粒与来自人或动物源肠杆菌科细菌的质粒具有高度同源性，在日本，伴侣犬猫可能是社区中mcr基因跨物种传播的重要储存宿主。
