不同饲养模式下宁蒗高原鸡源大肠杆菌耐药元件的分布特征

Distribution characteristics of drug-resistant elements of chicken-derived Escherichia coli in Ninglang Plateau under different feeding patterns

为了分析不同饲养模式下宁蒗高原鸡源大肠杆菌分离株中耐药基因、整合子和质粒型的分布特征,以便更好地保护和开发利用宁蒗高原鸡,试验采用PCR方法,在分离株系统分群的基础上,对耐药基因bla_(SHV)、bla_(TEM)、bla_(CTX-M-1)、bla_(CTX-M-2)、bla_(CTX-M-8/-25)、bla_(OXA-48)、tetA和tetB,整合子1和整合子2,10种质粒型进行了检测,并分析了不同质粒型间的关联性及系统分群、整合子、耐药基因、质粒型间的关联性。结果表明:B_(1)亚群的总检出率最高(68.21%),其次为B_(23)亚群(26.67%),不同饲养模式下不同亚群间的检出率存在差异;耐药基因bla_(TEM)的总检出率最高(81.54%),之后依次为bla_(OXA-48)(47.18%)、tetB(43.59%)和bla_(SHV)(42.05%),不同饲养模式下有些耐药基因的检出率存在差异;整合子1的总检出率(66.15%)高于整合子2(24.10%),笼养和混养模式下整合子1的检出率显著高于林下放养模式(P<0.05);质粒型IncI1的总检出率最高(97.44%),之后依次为IncP(82.05%)、IncN(63.59%)和IncFrep(56.41%)等,不同饲养模式下大部分质粒型的检出率存在差异;质粒型IncP、IncI1和IncN间,或这些质粒型与其他质粒型间具有高的关联性;整合子1与tetB、IncP和IncI1间有强关联性;IncP、IncFIB、IncI1、IncFrep、IncN与bla_(TEM)、tetB有关联性。说明不同饲养模式下,宁蒗高原鸡源大肠杆菌分离株中含有致病性分离株,且这些分离株携带不同的耐药基因、整合子和质粒型,在生产实践中需引起重视。

In order to analyze the distribution characteristics of drug-resistant genes,integrons and plasmid phenotypes in Ninglang Plateau chicken-derived E.coli isolates under different feeding patterns,so as to better protect and develop the utilization of Ninglang Plateau chickens,in the test,the drug resistance genes bla_(SHV),bla_(TEM),bla_(CTX-M-1),bla_(CTX-M-2),bla_(CTX-M-8/-25),bla_(OXA-48),tetA and tetB,integron 1 and integron 2,and 10 plasmid types were detected by PCR on the basis of systematic clustering of the isolates.The correlations among different plasmid types and the correlations among systematic subgroups,integrons,resistance genes and plasmid types were also analyzed.The results showed that subpopulation B_(1)had the highest detection rate(68.21%),followed by subpopulation B_(23)(26.67%);there were differences in detection rates among subpopulations in different feeding patterns.The detection rate of the resistance gene bla_(TEM)was the highest(81.54%),followed by bla_(OXA-48)(47.18%),tetB(43.59%),and bla_(SHV)(42.05%)in that order;there were differences in the detection rate of some of the resistance genes in different rearing patterns.The detection rate of integron 1(66.15%)was higher than that of integron 2(24.10%),and the detection rate of integron 1 was significantly higher in the cage and mixed pattern than in the forest free-ranging mode(P<0.05).The detection rate of plasmid IncI1 was the highest(97.44%),followed by IncP(82.05%),IncN(63.59%)and IncFrep(56.41%),etc.;there were differences in the detection rate of most of the plasmid types in different feeding patterns.There were high correlations between plasmids IncP,IncI1 and IncN,or between these plasmotypes and other plasmotypes,strong correlations between integron 1 and tetB,IncP and IncI1,and correlations between IncP,IncFIB,IncI1,IncFrep and IncN and bla_(TEM)and tetB.The results suggested that the Ninglang Plateau chicken-derived E.coli isolates contained pathogenic isolates under different feeding patterns,and these isolates carried different resistance genes,integrons and plasmid types,which needed to be paid attention to in the production practice.