猪场环境源大肠杆菌的耐药性调查及携带mcr-1和tet(X4)菌株的传播特征  

Investigation of Antimicrobial Resistance in Escherichia coli Isolated from Pig Farm Environment and Transmission Characteristics of mcr-1 and tet(X4)Positive Strains

作　　者：马胜男 王倩倩 申家兴 丁鹏云 冯一鸣 苑丽[1] 潘玉善[1] 胡功政[1] 贺丹丹 MA Shengnan;WANG Qianqian;SHEN Jiaxing;DING Pengyun;FENG Yiming;YUAN Li;PAN Yushan;HU Gongzheng;HE Dandan(College of Veterinary Medicine,Henan Agricultural University,Zhengzhou 450046,China;College of Modern Animal Husbandry,Henan Agricultural Vocational College,Zhengzhou 451450,China)

机构地区：[1]河南农业大学动物医学院,河南郑州450046 [2]河南农业职业学院现代牧业学院,河南郑州451450

出　　处：《中国兽医杂志》2024年第11期1-10,共10页Chinese Journal of Veterinary Medicine

基　　金：国家自然科学基金项目(32072923);河南省高校科技创新人才及创新团队支持计划(23HASTIT039,23IRTSTHN021)。

摘　　要：养殖场中抗菌药的长期使用促使耐药菌株快速出现和传播,并可以通过粪肥和污水向环境排放,给公共卫生带来巨大威胁。为了调查猪场环境源大肠杆菌的耐药情况,评估耐药基因的传播风险,本试验采集163份猪场粪便、污水和土壤样本,通过平板划线分离培养法分离大肠杆菌,通过药敏试验检测分离菌株对14种抗菌药物的耐药情况,聚合酶链式反应(PCR)检测临床重要耐药基因,脉冲场凝胶电泳(PFGE)检测菌株间的亲缘关系,接合试验和质粒复制子分型检测接合子的质粒类型。结果显示,共分离获得150株大肠杆菌,其中粪便源大肠杆菌耐药情况最严重,污水源大肠杆菌次之,土壤源大肠杆菌最低;污水源大肠杆菌耐药基因检出种类最多,粪便源大肠杆菌次之,土壤源大肠杆菌最少。10株携带黏菌素耐药基因mcr-1大肠杆菌和18株携带替加环素耐药基因tet(X4)大肠杆菌分离自粪便和污水样本,且多重耐药情况较为严重。10株携带mcr-1大肠杆菌经PFGE分为9种脉冲场图谱,其中9株与大肠杆菌C600接合成功,接合子中有IncFIA、IncW、IncFIB、IncI2和IncP五种质粒类型;18株携带tet(X4)大肠杆菌经PFGE分为15种脉冲场图谱,其中16株与大肠杆菌C600接合成功,接合子中有IncFIB、IncFrepB和IncHI1三种质粒类型。结果表明,必需持续监测猪场环境中的临床重要耐药基因,特别需要关注mcr-1和tet(X4)基因的流行情况,并且在养殖中合理使用黏菌素和四环素类抗生素。The prolonged use of antibiotics in livestock farming has accelerated the emergence and spread of resistant bacterial strains,which can be released into the environment via manure and wastewater,posing a significant threat to public health.To investigate antibiotic resistance in Escherichia coli(E.coli)from pig farm environments and assess the transmission risks of resistance genes,163 fecal,wastewater,and soil samples were collected from pig farms.E.coli strains were isolated using the streak plate method,and drug-sensitivity testing was conducted on the isolates against 14 antimicrobial agents.Clinically important resistance genes were detected via polymerase chain reaction(PCR),and the genetic relatedness between strains was assessed using pulsed field gel electrophoresis(PFGE).Conjugation experiments and plasmid replicon typing were performed to identify the plasmid types of the conjugants.The results showed that a total of 150 E.coli strains were isolated,with fecal-derived strains showing the highest levels of antibiotic resistance,followed by wastewater-derived strains,while soil-derived strains exhibited the lowest resistance.Wastewater-derived E.coli had the most diverse antibiotic resistance genes,followed by fecal-derived strains,and soil-derived strains had the least.Ten E.coli strains carrying the colistin resistance gene mcr-1 and 18 strains carrying the tigecycline resistance gene tet(X4)were isolated from fecal and wastewater samples,exhibiting significant multidrug resistance.PFGE revealed that the 10 mcr-1-positive strains were grouped into 9 pulsotypes,with 9 of these strains successfully conjugating with E.coli C600,and the conjugants carried five plasmid types:IncFIA,IncW,IncFIB,IncI2,and IncP.PFGE of the 18 tet(X4)-positive strains showed 15 pulsotypes,with 16 strains successfully conjugating with E.coli C600,and the conjugants carried three plasmid types:IncFIB,IncFrepB,and IncHI1.These findings underscore the need for continuous monitoring of clinically important resistance genes in pig fa

关 键 词：猪场环境 大肠杆菌 药敏试验 耐药基因 mcr-1 tet(X4) 

分 类 号：S852.61[农业科学—基础兽医学]