临床分离大肠杆菌磺胺敏感性及磺胺抗性相关基因的检测

Detection of Sulfanilamide Sensitivity and Sulfonamide Resistant Related Genes in Clinical Escherichia coli Isolates

对分离自中国东北牛(n=181)、猪(n=182)、鸡(n=146)和鹌鹑(n=55)的粪便及病变器官的564株大肠杆菌菌株进行磺胺敏感性与磺胺抗性基因检测。分别用肉汤微量稀释法和聚合酶链式反应检测磺胺敏感性和磺胺抗性基因。结果表明:在564株菌株中,235(41.7%)株对磺胺试剂敏感,329(58.3%)株对磺胺甲恶唑有抗性,190(33.7%)株对甲氧苄啶-磺胺甲恶唑有抗性;不同动物分离株的磺胺抗性比例不同,从牛、猪、鸡和鹌鹑中分离到的菌株int1基因的比例分别是12.2%、44.5%、40.4%、18.2%,sul1基因比例分别是5.5%、37.4%、28.1%、3.6%,sul2基因比例分别是39.2%、25.3%、29.5%、10.9%,但在牛、鸡、鹌鹑源菌株中未检测到sul3基因,在182株猪源大肠杆菌中检测到13株(7.1%)sul3基因阳性菌株。菌株的磺胺抗性与其包含的抗性基因之间不完全吻合。

Sulfonamides susceptibility testing and sulphonamides resistance gene detection were performed on a total of 564 clinical Escherichia coli isolates from faeces and pathological changed organs in cattle（n=181）,swine（n=182）,chickens（n=146）and quails（n=55）collected in Northeastern China.Broth microdilution and polymerase chain reaction（PCR）were used for the sulfonamides susceptibility testing and detection of sulphonamides resistance genes respectively.Of the 564 isolates,235（41.7%）E.coli isolates were susceptible to sulfonamides agents,while 329（58.3%）E.coli were resistant to sulfamethoxazole,190（33.7%）E.coli were resistant to trimethoprim-sulfamethoxazole.But different proportion of sulfonamides risistence was observed in different animal species.The frequency of int1 gene in E.coli isolates obtained from cattle,swine,chickens and quails was respectively 12.2%,44.5%,40.4% and 18.2%;that of sul1 gene was respectively 5.5%,37.4%,28.1% and 3.6%;that of sul2 gene was respectively 39.2%,25.3%,29.5% and 10.9%.Sul3 gene was not detected in E.coli isolates collected from cattle,chickens or quails in this study,while 13 sul3 genes were detected in 182（7.1%）swine E.coli strains.In conclusion,the sulfonamides resistance did not coincide with the presence of such genes completely in this study.