藏鸡致病性沙门菌的耐药性分析及质粒耐药基因的检测

Analysis of antimicrobial resistance and detection of plasmid-mediated resistance genes in pathogenic Salmonella isolated from Tibetan chickens

为研究藏鸡致病性沙门菌的耐药性及其质粒耐药基因携带情况,分别采用琼脂纸片扩散法和PCR扩增技术对14株藏鸡致病性沙门菌进行耐药表型及质粒耐药基因检测,并通过质粒接合试验验证其质粒耐药基因的水平传播。结果显示,14株分离菌对氨苄西林的耐药性(85.71%)最高,对阿莫西林(78.57%)、羧苄西林(78.57%)、复方新诺明(71.43%)、利福平(71.43%)、四环素(64.29%)的耐药比较严重,仅对头孢唑啉、庆大霉素、丁胺卡那敏感,且92.86%(13/14)的菌株表现为多重耐药性。此外,14株菌共检出blaTEM(78.57%)、blaCTX-M(71.43%)、blaOXA(42.86%)、blaPSE(50.00%)、blaDHA(14.28%)、blaCMY-2(50.00%)、qnrA(28.57%)、qnrS(42.86%)、aac(6′)-Ib-cr(35.71%)、oqxA(42.86%)和oqxB(35.71%)等11种质粒耐药基因。质粒耐药基因可通过接合试验水平转移,其接合成功率为57.14%(8/14)。结果表明,这14株藏鸡致病性沙门菌的耐药性比较严重,且广泛携带质粒耐药基因。

To investigate the characteristics of antimicrobial resistance and the prevalence of plasmidmediated resistance genes in 14 pathogenic Salmonellaisolates from Tibetan chickens,the resistant phenotypes and plasmid-mediated resistance genes were detected in 14 isolates by Kirby-Bauer method and PCRsequencing.Conjugation experiments were performed among plasmid-mediated resistance genes.The results indicated that the highest prevalence of resistance was to ampicillin（85.71%）,followed by amoxicillin（78.57%）,carbenicillin（78.57%）,sulphame-thoxazole（71.43%）,rifampicin（71.43%）,and tetracycline（64.29%）,but all isolates were sensitive to cefazolin,gentamicin,and amikacin.Total 92.86%（13/14）of the isolates were multidrug resistance.Additionally,the plasmid-mediated resistance genes blaTEM,blaCTX-M,blaOXA,blaPSE,blaDHA,blaCMY-2,qnrA,qnrS,aac（6′）-Ib-cr,oqxAand oqxB were found in 78.57%,71.43%,42.86%,50.00%,14.28%,50.00%,28.57%,42.86%,35.71%,42.86% and35.71% of 14 isolates,respectively.The plasmid-mediated resistance genes were transferred from 57.14%（8/14）of the Salmonellaisolates into the E.coli J53 by conjugation experiments.Our findings showed that the Salmonellaisolated from Tibetan chickens were serious resistance to antimicrobial agents,and plasmid-mediated resistance genes were widely existed.