辽宁地区猪源大肠埃希菌整合子携带情况调查与分析

查明辽宁地区整合子在猪源大肠埃希菌中的分布及整合子携带耐药基因盒的种类,可为该病的综合防控提供科学依据。本研究利用整合酶基因PCR扩增法检测整合子,并对整合子可变区进行扩增测序。结果表明,71.43%(40/56)的菌株为Ⅰ类整合子阳性,1.79%(1/56)的菌株同时为Ⅰ类和Ⅱ类整合子阳性,未检测到Ⅲ类整合子;87.8%(36/41)的菌株表现为Ⅰ类整合子可变区扩增阳性,扩增产物大小在116bp~2 307bp之间,100%(1/1)菌株表现为Ⅱ类整合子可变区扩增阳性,大小为2 106bp;整合子可变区含有编码对氨基糖苷类抗生素耐药的基因(aadA1、aadA2、aadA5、aadA22、aadB、aacA4和sat2),编码对磺胺类抗生素耐药的基因(dfrA1、dfrA12、dfrA17),编码对氯霉素抗生素耐药的基因(cmlA1、cmlA6)。因此,整合子在大肠埃希菌中广泛存在,辽宁地区大肠埃希菌中整合子主要携带编码对氨基糖苷类、磺胺类和氯霉素耐药基因盒。

Investigation and Analysis of Whole Carrying Integrons of Escherichia coli from Swine in Liaoning Area

In order to understand the distribution of integrons and types of drug resistance gene cassette in Escherichia coli from swine in Liaoning area,and to provide a scientific basis for the comprehensive prevention and control of the disease,the integrons were detected by integrase gene PCR,and variable region of the integron was amplified and sequenced.Results showed that 71.43%(40/56)of the strains were shown to be class Ⅰintegron positive,1.79%(1/56)of the strains were shown to be classⅠ and classⅡ integron positive,and no classⅢ integron was detected.87.8%(36/41)of the positive strains of classⅠintegron contained a gene cassette,which sized from 116 bp to 2 307 bp,100%(1/1)classⅡ integron positive strain contained a 2 106 bp size gene cassette.These gene cassettes included genes encoding resistance to aminoglycosides (aadA1,aadA2,aadA5,aadA22,aadB,aacA4,sat2),sulfonamides (dfrA1,dfrA12,dfrA17),chloramphenicol (cmlA1,cmlA6).Therefore,integrons are widespread in E.coli,the E.coli mainly carried resistance gene cassettes of aminoglycosides,sulfonamides,and chloramphenicol in Liaoning.