奶牛场环境中耐药大肠杆菌的分离及耐药基因遗传环境分析  

Isolation of Antibiotic-Resistant Escherichia coli and Analysis of the Genetic Environment of Antibiotic Resistance Genes from the Environment of a Dairy Farm

作　　者：王灵舸 沈留红[2] 唐俊妮[3] 韩新锋[2] 朱成林 赵珂 邹立扣 WANG Lingge;SHEN Liuhong;TANG Junni;HAN Xinfeng;ZHU Chenglin;ZHAO Ke;ZOU Likou(College of Resources,Sichuan Agricultural University,Chengdu 611130,China;College of Veterinary Medicine,Sichuan Agricultural University,Chengdu 611130,China;College of Food Science and Technology,Southwest Minzu University,Chengdu 601225,China)

机构地区：[1]四川农业大学资源学院,成都611130 [2]四川农业大学动物医学院,成都611130 [3]西南民族大学食品科学与技术学院,成都601225

出　　处：《生态毒理学报》2025年第1期329-343,共15页Asian Journal of Ecotoxicology

基　　金：四川省重大科技专项(2022ZDZX0017);凉山州科技局项目(23CGZH0006)。

摘　　要：为了解四川某奶牛场环境中大肠杆菌的耐药情况及耐药基因(antibiotic resistance genes,ARGs)的遗传环境,对从养殖场采集的样品进行大肠杆菌的分离鉴定,进行最小抑菌浓度(the minimum inhibitory concentrations,MICs)测定,并选择多重耐药大肠杆菌进行全基因组测序分析。共采集36份样品,分离得到18株大肠杆菌。药敏试验显示大肠杆菌对四环素、阿莫西林的耐药率较高,且大部分表现为多重耐药。耐药基因检测发现所有大肠杆菌均携带耐药基因blaTEM、ampC、tetA和qnrA,53.33%的大肠杆菌携带blaCTX-M基因,55.55%的大肠杆菌携带tetM基因。通过二代全基因组测序,8株多重耐药大肠杆菌均检测到大量耐药基因及毒力基因,对其耐药基因环境进行分析,发现大肠杆菌β-内酰胺类耐药基因、四环素类耐药基因上下游环境高度一致,并存在转座子、插入序列(insertion sequences,ISs)等可移动遗传元件(mobile genetic elements,MGEs),有助于耐药基因在环境中的传播。其中,发现bla_(CTX-M-15)基因上下游存在与WbuC家族杯状折叠金属蛋白基因关联的保守结构。该研究对奶牛场科学合理使用抗生素,以及对养殖环境中耐药菌(antibiotic resistant bacteria,ARB)和耐药基因的监测具有重要意义。To understand the antibiotic resistance and the antibiotic resistance genes(ARGs)of Escherichia coli from a dairy farm in Sichuan Province,Escherichia coli strains were isolated from the dairy farm.The minimum inhibitory concentrations(MICs)were determined,and whole-genome sequencing of multi-drug resistance strains was implemented.A total of 36 samples were collected,and 18 strains of Escherichia coli were isolated.Antimicrobial susceptibility test demonstrated that Escherichia coli had high resistance rate to tetracycline and amoxicillin,and most of the strains presented multi-drug resistance.All strains carried blaTEM,ampC,tetA and qnrA,53.33%of strains carried blaCTX-M,and 55.55%of strains carried tetM.Whole-genome sequencing revealed that a large number of ARGs and virulence genes were identified in all 8 strains of Escherichia coli.The analysis of ARGs revealed that the upstream and downstream regions of theβ-lactam-resistance genes and tetracycline-resistance genes of Escherichia coli were highly identical and harbored mobile genetic elements(MGEs),such as transposons and insertion sequences(ISs),which contributed to the spread of ARGs in the environment.Additionally,there was a highly conserved structure associated with cupin fold metalloprotein gene of WbuC family in the upstream and downstream regions of bla_(CTX-M-15).This study has great significance for the rational utilization of antibiotics in dairy farms and the monitoring of antibiotic resistant bacteria(ARB)and ARGs in the breeding environment.

关 键 词：奶牛场 大肠杆菌 耐药性 耐药基因环境 

分 类 号：X171.5[环境科学与工程—环境科学]