奶牛养殖场环境中耐药基因bla_(NDM)的分布和传播特性分析  

Analysis of distribution and transmission characteristics of antibiotic resistance gene bla_(NDM) in the dairy farm environment

作　　者：马妍 陈帅印[2] 丁冬 王亚 朱静媛 MA Yan;CHEN Shuaiyin;DING Dong;WANG Ya;ZHU Jingyuan(Department of Environmental Health,College of Public Health,Zhengzhou University,Zhengzhou 450001;Department of Epidemiology,College of Public Health,Zhengzhou University,Zhengzhou 450001)

机构地区：[1]郑州大学公共卫生学院环境卫生学教研室,郑州450001 [2]郑州大学公共卫生学院流行病学教研室,郑州450001

出　　处：《郑州大学学报（医学版）》2023年第6期828-835,共8页Journal of Zhengzhou University(Medical Sciences)

基　　金：国家自然科学基金项目(U1804184)。

摘　　要：目的:了解奶牛养殖场环境中耐药基因bla_(NDM)的分布情况及传播特性。方法:采用PCR法从河南省焦作市某地2个奶牛养殖场的奶牛养殖场饲养环境、动物(鼻拭子、粪便)和工人(咽拭子、粪便)样本中检测并分离bla_(NDM)阳性菌株,对bla_(NDM)基因阳性大肠杆菌进行系统进化群、多位点序列分型、耐药表型和耐药基因分析;通过接合试验验证bla_(NDM)基因的可转移性;质粒稳定性试验分析携带bla_(NDM)基因的质粒在宿主细菌中的稳定性。结果:bla_(NDM)基因在奶牛场的总检出率为35.5%,成年母牛中bla_(NDM)基因的阳性检出率高于犊牛(P<0.001),从动物和工人粪便共分离出17株bla_(NDM-5)阳性大肠杆菌,bla_(NDM-5)阳性大肠杆菌属于系统进化群A群(11.8%)和B1群(88.2%),存在3种不同ST型(ST_(48)、ST_(n-1)、ST_(n-2))。17株bla_(NDM-5)阳性大肠杆菌均是多耐药菌株。所有菌株的bla_(NDM)基因位于接合性质粒,可以通过质粒接合转移至受体菌株中,且经过36代无抗培养后仍能在宿主细菌中稳定存在。结论:bla_(NDM)基因在奶牛养殖场流行率较高,主要的细菌宿主是大肠杆菌,且bla_(NDM)基因可通过质粒的接合转移进行水平传播。Aim:To understand the distribution and transmission characteristics of antibiotic resistance gene bla_(NDM) in the dairy farm environment.Methods:The bla_(NDM)-positive strains were detected and isolated by PCR from dairy farm feeding environment,animal(nasal swabs,feces) and worker(throat swabs,feces) samples from 2 dairy farms in Jiaozuo City,Henan Province.The bla_(NDM)-positive Escherichia coli were tested for phylogenetic groups,multilocus sequence typing,drug resistance phenotypes,and drug resistance genes.The transferability of bla_(NDM) gene was tested by conjugation assay,and the stability of plasmid carrying bla_(NDM) gene in host bacteria was analyzed by plasmid stability assay.Results:The overall detection rate of bla_(NDM) gene in dairy farms was 35.5%.The detection rate of bla_(NDM) gene in adult dairy cows was higher than that in calves(P<0.001).Seventeen strains of bla_(NDM-5)-positive Escherichia coli were isolated from fecal samples of animals and workers.The bla_(NDM-5)-positive Escherichia coli belonged to phylogenetic groups A(11.8%) and B1(88.2%),with 3 different ST types(ST_(48),ST_(n-1),ST_(n-2)).Seventeen bla_(NDM-5)-positive Escherichia coli were multidrug-resistant.The bla_(NDM) gene of all strains was located in a conjugative plasmid,which could be transferred to the recipient strain by plasmid conjugation and could still exist stably in the host bacteria after 36 generations of antibiotic-free culture.Conclusion:The prevalence of bla_(NDM) gene in dairy farms is high,the main bacterial host is Escherichia coli,and the bla_(NDM) gene can be transmitted horizontally through the conjugative transfer of plasmids.

关 键 词：奶牛养殖场 大肠杆菌 bla_(NDM)基因 多位点序列分型 药敏试验 

分 类 号：S823[农业科学—畜牧学]