Molecular characterization of blaKHM-1 encoding plasmid in an Enterobacter hormaechei subsp. hoffmannii isolate from blood culture

Autoři: Kaoru Umeda aff001;  Hiromi Nakamura aff001;  Akira Fukuda aff001;  Takahiro Yamaguchi aff001;  Yuki Matsumoto aff002;  Daisuke Motooka aff002;  Shota Nakamura aff002;  Ryuji Kawahara aff001
Působiště autorů: Division of Microbiology, Osaka Institute of Public Health, Osaka, Japan aff001;  Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan aff002
Vyšlo v časopise: PLoS ONE 15(1)
Kategorie: Research Article
doi: 10.1371/journal.pone.0227605


KHM-1 was first reported in 1997 in Japan as a novel metallo-β-lactamase mediated by Citrobacter freundii carrying pKHM-1 plasmid. There have been few reports in the clinical field since then. A blaKHM-1–positive Enterobacter hormaechei subsp. hoffmannii in E. cloacae complex, isolate OIPH-N069 was isolated from an inpatient blood culture in 2016. The isolate was characterized by whole-genome sequencing, comparative analysis of the blaKHM-1 encoding plasmid, antimicrobial susceptibility tests, and bacterial conjugation. OIPH-N069 was classified into ST78 of E. cloacae complex, and was multidrug resistant because of the presence of antimicrobial resistance genes in addition to blaKHM-1 on its chromosome and plasmids. blaKHM-1 was located on 136,816 bp of the IncA/C2 plasmid pN069-1, which could be transferred to different bacterial species. The backbone structure, genetic arrangement of the class 1 integron cassette, and the blaKHM-1 gene located downstream of the IncA/C2 antibiotic resistance island, ARI-A, in pN069-1 and pKHM-1 were identical. Horizontal gene transfer of the blaCTX-M-2–ISEcp1 resistance gene module only occurred with pN069-1. The study findings indicate not only the structural conservation of blaKHM-1 encoding plasmids over time and across species, but also the risk of the spread of blaKHM-1 encoding plasmids to other bacterial species and the accumulation of additional resistance genes.

Klíčová slova:

Antimicrobial resistance – Antimicrobials – Comparative genomics – Enterobacteriaceae – Genome analysis – Japan – Plasmids – Sequence databases


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2020 Číslo 1