Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada.
Department of Population Medicine, University of Guelph, Guelph, Canada.
Microb Drug Resist. 2019 Oct;25(8):1250-1256. doi: 10.1089/mdr.2018.0406. Epub 2019 Jun 3.
Food-producing animals are recognized to play a role in the epidemiology of antimicrobial resistance in Canada. However, the presence of resistant organisms in particular groups of animals, such as chickens raised in small-holder flocks, has not been studied. The purpose of this study was, therefore, to identify and characterize possessing broad-spectrum β-lactamase genes among a collection of third-generation cephalosporin-resistant isolates recovered from 205 small flocks in southern Ontario. Extended-spectrum β-lactamase (ESBL; CTX-M-1) positive strains were isolated from 26 out of 205 flocks (12.7%), whereas 39 strains possessing AmpC (CMY-2) were grown from 31 out of 205 flocks (15.1%). Pulsed-field gel electrophoresis (PFGE) revealed that the isolates were genetically heterogeneous. Further testing by multi-locus sequence typing confirmed that none of the PFGE-defined clusters belonged to ST131. Our results suggest that the dissemination of this resistance in bacteria isolated from chickens in small-holder flocks may be associated with the spread of plasmids rather than particular clones and that these isolates do not possess the ESBL types most commonly associated with human infections (CTX-M-15).
食源性动物被认为在加拿大的抗生素耐药性流行病学中发挥作用。然而，在特定动物群体中，如在小型散养家禽中存在耐药菌，这方面的研究尚未开展。因此，本研究的目的是从安大略省南部 205 个小型家禽群中回收的第三代头孢菌素耐药分离株中，鉴定和描述具有广谱β-内酰胺酶基因的 。从 205 个禽群中分离出 26 株（12.7%）产超广谱β-内酰胺酶（CTX-M-1）阳性菌株，从 31 个禽群中分离出 39 株具有 AmpC（CMY-2）的菌株（15.1%）。脉冲场凝胶电泳（PFGE）显示分离株具有遗传异质性。多位点序列分型进一步检测证实，PFGE 定义的簇中没有一个属于 ST131。我们的研究结果表明，从小型散养家禽中分离出的细菌中这种耐药性的传播可能与质粒的传播有关，而不是与特定的克隆有关，并且这些分离株不具有与人类感染最相关的 ESBL 类型（CTX-M-15）。
