大肠杆菌分离鉴定及其耐药性试验

Isolation, Identification and Antimicrobial Resistance Patterns of Escherichia coli from Sheep

为了确定采集自内蒙古地区某牧场的病料内的病原菌,对其进行细菌的分离培养。将分离培养出的2株病原菌进行16S rDNA扩增、细菌生化鉴定、致病性试验以及细菌耐药性试验。结果表明,分离菌在伊红美蓝琼脂培养基上可生长出暗红色或黑色并且带有金属光泽的菌落;镜检可见,分离菌为革兰阴性杆菌;分离菌生化鉴定结果与大肠杆菌标准菌株ATCC 25922测定的结果相一致;分离菌的16S rDNA与大肠杆菌标准菌株16S rDNA PCR扩增结果相一致;分离到的2株大肠杆菌均具有致病性,对多种抗生素均有耐药性。结果提示,该次分离得到的病原菌主要为具有多重耐药性的致病性大肠杆菌。

The objective of this study was to identify the bacterial causative agents associated with the incidence of infectious disease cases in a sheep farm in Inner Mongolia, and to characterize the virulence and antimicrobial resistance patterns of the isolates. Clinical samples were recovered from the diseased sheep to isolate bacterial strains with eosin methylene blue (EMB) agar. Subsequently, the isolates were phenotypically and molecularly identified to genus level, and their virulence and antimicrobial resistance patterns were characterized. Two gram-negative strains with typical growth features of Escherichia coli in EMB agar were obtained. The isolates were confirmatively identified as Escherichia coli by biochemical reactions and 16S rDNA PCR and sequence analysis. Both of the isolated strains showed pathogenicity to experimental animals and exhibited resistance to several antimicrobial agents commonly used in veterinary clinic. Our results demonstrated the prevalence of the antibiotic resistant and pathogenic Escherichia coli in this sheep farm.