猪源肠外致病性大肠埃希氏菌的分离鉴定与药敏试验

Isolation,Identification and Drug Sensitivity Test of a Swine-derived Extraintestinal Pathogenic Escherichia coli

为对陕西某猪场仔猪肺炎病例进行确诊,无菌采集患病仔猪肺脏,并进行细菌分离培养、生化试验、16S rRNA基因测序、小鼠致病性试验、药敏试验以及耐药基因检测。结果表明,分离到的菌株其培养特性和生化试验与大肠埃希氏菌一致,16S rRNA基因测序与大肠埃希氏菌的同源性为98%;小鼠致病性试验验证了该菌株的致病性;药敏试验显示该菌对氨苄西林、复方阿莫西林、庆大霉素、四环素、头孢噻呋钠、头孢他啶、恩诺沙星、氟苯尼考和磺胺异恶唑等9种抗菌药物表现耐药,对替加环素、美罗培南和多黏菌素B敏感;耐药基因检测结果发现该菌携带sul3、tetA和TEM等耐药基因。研究结果确定了引起某猪场仔猪肺炎的病原菌,并对其生物学特性、耐药情况进行了研究,为临床诊断治疗提供参考。

In order to diagnose the pathogen causing piglet pneumonia in a large-scale pig farm in Shaanxi province,the diseased parts of lungs were aseptically taken for bacterial isolation,microscopic examination,biochemical experiment,16S rRNA gene sequencing,pathogenicity test in mice,antimicrobial sensitive test and drug resistance genes detection.The results showed that the culture characteristics and biochemical tests of the isolated strain was consistent with Escherichia coli.The 16S rRNA gene sequencing result was 98%homologous to Escherichia coli.The pathogenicity of the strain was verified by mouse pathogenicity test.The results of antimicrobial sensitivity test showed that the isolate was resistant to nine antimicrobials,such as ampicillin,compound amoxicillin,gentamicin,tetracycline,ceftiofur sodium,ceftazidime,enrofloxacin,florfenicol and sulfaisoxazole,and sensitive to tegacyclin,meropenem and polymyxin B.The results of drug resistance genes showed that the isolate carried sul3,tetA and TEM genes.This study identified the pathogenic bacterium causing piglet lung inflammation,and studied its biological characteristics and drug resistance,so as to provide basic data and reference for clinical diagnosis and treatment.