摘要
[目的]了解新疆维吾尔自治区塔额垦区牛源大肠杆菌耐药性及CTX-M基因和毒力基因携带情况。[方法]从塔额垦区某牛场采集16份牛腹泻粪样,通过选择性培养、革兰染色镜检、16S rDNA PCR扩增及测序进行大肠杆菌分离鉴定。利用PCR法对牛源大肠杆菌分离株进行分子分型(系统发育群和脂多糖核心型)以及耐药基因、CTX-M基因亚型、毒力基因检测;分别使用K-B纸片法、CTX与TCL双纸片法进行药物敏感性试验和产ESBLs大肠杆菌鉴定;采用结晶紫染色法半定量检测菌株的生物被膜形成能力。[结果]根据菌落生长特征、革兰染色特性及16S rDNA测序结果,从16份牛腹泻粪样中分离鉴定出16株大肠杆菌,分离率为100%;系统发育群主要为B1群(14/16,87.50%),脂多糖核心型多为R1型(15/16,93.75%)。分离菌株对青霉素、利福平、复方新诺明表现出较强耐药性,耐药率分别为100%、68.75%、68.75%;对多黏菌素、替加环素、美罗培南敏感,耐药率均为0;有12株(75.00%)具有多重耐药表型;有11株(68.75%)产ESBLs;有15株(93.75%)可形成生物被膜。16株大肠杆菌中共检出17种耐药基因,CTX-M、ant(6′)、sul1等8种耐药基因的检出率为100%;有14株(87.50%)为CTX-M-1G基因亚型;共检出12种毒力基因,iroN、ompA、yijP等5种毒力基因的检出率为100%。[结论]新疆维吾尔自治区塔额垦区牛源大肠杆菌CTX-M基因检出率较高,携带多种耐药基因和毒力基因,耐药性较强,对该地区牛健康养殖存在潜在威胁,应加强该地区CTX-M型大肠杆菌的流行情况监控。
[Objective]The aim of the present study was to characterize the antimicrobial resistance profile as well as the prevalence of CTX-M gene and virulence genes of the Escherichia coli(E.coli)strains derived from cattle in Ta′e reclamation area,Xinjiang Uygur Autonomous Region.[Method]A total of 16 fecal samples of cattle with diarrhea were collected from a cattle farm in Ta′e reclamation area.The selective culture,Gram staining and microscopy,and 16S rDNA PCR amplification and sequencing were used to isolate and identify the E.coli strains.The PCR assay was used for the molecular typing(phylogenetic group and lipopolysaccharide core type)as well as the detection of antimicrobial resistance genes,CTX-M gene subtypes and virulence genes of the E.coli isolates.The K-B disk diffusion method as well as the CTX and TCL dual disk diffusion method were utilized for antimicrobial sensitivity test and ESBLs-producing E.coli identification,respectively.The biofilm formation ability of the E.coli isolates were semi-quantitatively analyzed using crystal violet staining method.[Result]Based on the colony growth feature,Gram staining characteristic and 16S rDNA sequencing result,a total of 16 E.coli strains were isolated and identified from the 16 fecal samples of the diarrhoeal cattle,with a separation rate of 100%.Most of the E.coli isolates belonged to the phylogenetic group B1(14/16,87.50%)and the lipopolysaccharide core type R1(15/16,93.75%).The E.coli isolates exhibited high-level resistance to penicillin,rifampicin and compound sulfamethoxazole,with resistance rates of 100%,68.75%and 68.75%,respectively,while they were sensitive to polymyxin,tigecycline and meropenem,with resistance rates all being 0.Twelve strains(75.00%)had multi-drug resistant phenotype,11 strains(68.75%)produced ESBLs,and 15 strains(93.75%)were capable of forming biofilm.A total of 17 antimicrobial resistance genes were detected as positive among the 16 E.coli isolates,and the detection rates for 8 antimicrobial resistance genes such as CTX-M,ant(6′)and sul1 were 100%.Fourteen strains(87.50%)were identified as the CTX-M-1G gene subtype.In addition,a total of 12 virulence genes were detected as positive,among which,5 virulence genes including iroN,ompA and yijP had 100%detection rate.[Conclusion]A high prevalence of CTX-M gene was observed in the cattle derived E.coli strains in Ta′e reclamation area of Xinjiang Uygur Autonomous Region.Furthermore,these isolates harbored multiple antimicrobial resistance genes and virulence genes,and had high-level antimicrobial resistance,which posed potential threats to the healthy farming of cattle in this region.Therefore,it is necessary to strengthen the monitoring of the CTX-M type E.coli prevalence in this region.
作者
赵耀
邢国锋
苏帆帆
高攀
彭健
吴自豪
吴静
ZHAO Yao;XING Guofeng;SU Fanfan;GAO Pan;PENG Jian;WU Zihao;WU Jing(College of Animal Science and Technology,Tarim University/Engineering Laboratory of Tarim Animal Disease Diagnosis and Control,Xinjiang Production and Construction Corps,Aral 843300,China;Agricultural Science Institute(Institute of Animal Science)of the Ninth Division,Xinjiang Production and Construction Corps,Emin 834601,China;College of Life Science and Technology,Tarim University,Aral 843300,China)
出处
《畜牧与饲料科学》
2024年第1期94-101,共8页
Animal Husbandry and Feed Science
基金
新疆生产建设兵团第九师科技计划项目“牛羊重要细菌性传染病的综合防治与示范”(2021JS001)。
关键词
大肠杆菌
CTX-M基因
分子分型
耐药性
毒力基因
Escherichia coli
CTX-M gene
molecular typing
antimicrobial resistance
virulence gene
