牛源大肠杆菌CTX-M型基因耐药性与流行性分析  

Drug resistance and epidemic analysis of CTX-M genes in bovine Escherichia coli

作　　者：路宁宁 王玮玮 吴灵玉 魏小娟[1] 李冰[1] 张继瑜[1] LU Ning-ning;WANG Wei-wei;WU Ling-yu;WEI Xiao-juan;LI Bing;ZHANG Ji-yu(Key Laboratory of Veterinary Drug Innovation,Ministry of Agriculture and Rural Affairs,Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS,Lanzhou 730050,China)

机构地区：[1]中国农业科学院兰州畜牧与兽药研究所农业农村部兽药创制重点实验室,甘肃兰州730050

出　　处：《中国兽医科学》2022年第2期244-252,共9页Chinese Veterinary Science

基　　金：国家自然科学基金资助项目(3187520)。

摘　　要：为了解不同养殖模式下牛源大肠杆菌对抗菌药物的耐药性及CTX-M型基因流行分布特征,本研究从甘肃和新疆采集肉牛、奶牛和牦牛粪便样品,经分离鉴定得到220株大肠杆菌,采用纸片扩散法(K-B法)对分离株进行药物敏感性测定,通过PCR法检测CTX-M型基因和整合子基因型,利用多重PCR法对CTX-M阳性菌株进行种族进化关系分析。结果显示,肉牛源分离株主要对4类抗菌药物产生耐药,耐药率为17.98%;奶牛源分离株主要对5类抗菌药物产生耐药,耐药率为22.39%;牦牛源分离株主要对3类抗菌药物产生耐药,耐药率为14.06%。肉牛源、奶牛源和牦牛源分离株中均检测到了CTX-M-1G和CTX-M-9G基因,其亚型以CTX-M-55、CTX-M-79和CTX-M-14为主;91株CTX-M阳性大肠杆菌中有85株菌株均仅携带Ⅰ类整合子整合酶基因Int1,携带率为93.41%;种族进化关系分析显示,CTX-M阳性菌株主要分布在B1群(75.82%),其次分别为A群(9.89%)、C群(8.79%)、E群(3.30%)和D群(1.10%)。研究结果提示,奶牛源大肠杆菌不仅多重耐药最严重,而且以CTX-M-55+CTX-M-79优势基因型流行最广。不同养殖模式下牛源大肠杆菌耐药性及CTX-M基因流行性差异与长期滥用或不合理使用抗菌药物产生的选择压力有关。To understand the resistance of E.coli of bovine origin to antibiotics and the epidemiological distribution characteristics of CTX-M type genes under different breeding patterns.In this study,fecal samples were collected from beef cattle,dairy and yaks in Gansu and Xinjiang Provinces.220 E.coli strains were isolated and identified,drug susceptibility of the isolates was determined by disk diffusion method(K-B method),CTX-M type genes and integrons were detected by PCR genotypes,and the CTX-M positive strains were analyzed for racial evolutionary relationships using multiplex PCR.The results showed that beef-derived isolates were mainly resistant to 4 classes of antibiotics,with a drug resistance rate of 17.98%,dairy-derived isolates were mainly resistant to 5 classes of antibiotics,with a drug resistance rate of 22.39%,and yak-derived isolates were mainly resistant to 3 classes of antibiotics,with a drug resistance rate of 14.06%.The CTX-M-1 G and CTX-M-9 G genes were detected in the beef-,cow-and yak-derived isolates,and their isoforms were dominated by CTX-M-55,CTX-M-79 and CTX-M-14.85 of the 91 CTX-M positive E.coli strains only carried class-1 integron integrase gene Int1,with a carriage rate of 93.41%.The racial evolutionary relationship analysis showed that CTX-M positive strains were mainly distributed in cluster B1(75.82%),followed by cluster A(9.89%),cluster C(8.79%),cluster E(3.30%)and cluster D(1.10%),respectively.The results of study suggest that E.coli of dairy origin was not only the most multi-drug resistant but also the most prevalent with CTX-M-55+CTX-M-79 dominant genotype.Difference in bovine E.coli resistance and CTX-M genes prevalence from different feeding patterns are associated with selection pressure generated by long-term misuse or irrational use of antibiotics.

关 键 词：牛源大肠杆菌 CTX-M基因 耐药性 流行特征 

分 类 号：S852.612[农业科学—基础兽医学]