犬源大肠杆菌耐药与毒力的分子特征

Molecular characterization of pathogenetic Escherichia coli isolated from dogs

从9份病犬血便和6份健康犬粪便样品中分离出17株大肠杆菌,分别进行了生化鉴定,耐药基因blaCTX-M、blaTEM和blaSHV以及24种毒力基因的PCR扩增,13种抗菌药的药敏检测,以及ESBL表型鉴定、MLST分型、菌株分群和质粒分型。研究发现,病犬分离出的大肠杆菌多为致病性的ESBL表型耐药菌,携带多种质粒以及blaCTX-M和/或blaTEM-1基因,检测到10种毒力相关基因,健康犬分离出的大肠杆菌对多数抗菌药敏感,绝大部分未检测到质粒及blaCTX-M、blaTEM和blaSHV耐药基因。本研究从健康犬大肠杆菌分离株检测到3种新的ST型,分别为ST4001、ST4002和ST4003。结果表明,犬致病性大肠杆菌耐药情况十分严重,其临床治疗难度以及耐药性传播风险将加大,并对于人类健康具有潜在威胁,应予以重视。

A total of 17 Escherichia coli isolates collected from fecal samples of diseased dogs （n= 9） and healthy dogs （n=6） were investigated using biochemistry and molecular methods,such as β-lactamases, antimicrobial susceptibility testing, confirmatory test for ESBL, plasmid replicon typing,phylogenetic grouping and ST determination. The results showed that isolates from dis- eased dogs were resistant to more antibiotics than isolates from healthy dogs. Most of them carried several kinds of plasmids, produced CTX-M and/or TEM-1. No isolates from healthy dogs pro- duced CTX-M, TEM and SHV, and less isolates carried plasmids. We also identified three novel ST determinations,ST4001,ST4002 and ST4003. More attention should be paid to the use of antimi- crobials and the occurrence of antimicrobial resistance in companion animals.