Diversity of Plasmid Replicons Encoding thebla_CMY-2Gene in Broad-Spectrum Cephalosporin-ResistantEscherichia colifrom Livestock Animals in Japan

Abstract

Broad-spectrum cephalosporin (BSC) resistance has increased in Escherichia coli isolates from broiler chickens in Japan since 2004. The purpose of this study was to understand the epidemiology of BSC-resistant E. coli in livestock animals. Among 3274 E. coli isolates from 1767 feces of apparently healthy animals on 1767 farms between 2004 and 2009, 118 ceftiofur (CTF)-resistant isolates (CTF MIC ≥4 μg/mL) were identified on 74 farms. After elimination of apparently clonal isolates from a single animal, 75 selected CTF-resistant isolates (62 isolates from 61 broiler chickens, 10 isolates from 10 layer chickens, two isolates from two cows, and one isolate from a pig) were characterized. The bla(CMY-2) gene was most frequently detected in 50 isolates, followed by bla(CTX-M) (CTX-M-2: six isolates; CTX-M-14: four isolates; CTX-M-25: two isolates; CTX-M-1: one isolate) and bla(SHV) (SHV-12: seven isolates; SHV-2, SHV-2a, SHV-5: one isolate each). In particular, 42 of 62 broiler chicken isolates harbored bla(CMY-2). Pulsed-field gel electrophoresis analyses using XbaI revealed divergent profiles among the BSC-resistant isolates. The incompatibility groups of bla(CMY-2) plasmids from 34 of the 42 broiler chicken isolates belonged to IncIγ (10 isolates), IncA/C (nine isolates), IncB/O (seven isolates) and IncI1 (six isolates), or were nontypeable (two isolates). Co-transmission of resistance to non-β-lactam antibiotics was observed in transconjugants with IncA/C plasmids, but not with IncI1, IncIγ, and IncB/O plasmids except for one isolate with IncB/O. Our findings suggest that the bla(CMY-2) gene is a key player in BSC-resistant E. coli isolates and that coselection is unlikely to be associated with the abundance of bla(CMY-2) plasmids, except for IncA/C plasmids.

野生动物(野鸟)对全球耐药基因传播的影响

“…Among wild animals, bla CMY-2 has been reported to be mainly associated with IncI1 plasmids in E. coli from Dutch wild birds and wild seagulls in the US (Poirel et al, 2012; Veldman et al, 2013). Other plasmid types, such as IncB/O, IncK, and IncF, have also been identified as carriers of bla CMY-2 in wildlife (Poirel et al, 2012; Veldman et al, 2013), as previously reported in humans, companion animals, broiler chickens, and retail meat (Bortolaia et al, 2014; Hansen et al, 2016; Hiki et al, 2013; So et al, 2012; Vogt et al 2014). Thus far, the IncA/C plasmid, a major carrier of bla CMY-2 , has not yet been identified in wild animals.…”

Recent Emergence of Escherichia coli with Cephalosporin Resistance Conferred by bla CTX-M on Washington State Dairy Farms

“…Ceftiofur, a veterinary third-generation cephalosporin, is used commonly to treat infectious diseases in dairy cattle (12). Resistance to ceftiofur is correlated with clinically relevant drug resistance in human medicine (13) and has been used as a phenotypic marker for targeted research of third-generation cephalosporin resistance genes in bovine bacterial flora (14)(15)(16). The E. coli isolates used in the retrospective study were obtained during previous studies using various selection methods focused primarily on ceftiofur resistance.…”

Phylogenetic grouping, epidemiological typing, analysis of virulence genes, and antimicrobial susceptibility of Escherichia coli isolated from healthy broilers in Japan

“…Fresh fecal samples were collected from two or three healthy broilers at the different farms in each prefecture as previously described [14]. E. coli was isolated from the fecal samples using desoxycholate–hydrogen sulfate–lactose agar (Eiken Co., Ltd., Japan).…”