中国畜牧兽医2023，Vol.50Issue(12)：5022-5031,10.DOI:10.16431/j.cnki.1671-7236.2023.12.024
犊牛源肠外致病性大肠杆菌分离鉴定、致病性及耐药性分析
Isolation,Identification,Pathogenicity and Drug Resistance Analysis of Extraintestinal Pathogenic Escherichia coli from Calves
摘要
Abstract
[Objective]The purpose of this study was to identify the bacterial pathogens and its biological characteristics causing the death of calves in a large-scale cattle farm in Kashi,Xinjiang,so as to provide reference for the treatment of bacterial-associated diseases and rational drug for the area.[Method]The pathological dissection and pathogen isolation on dead calves were conducted,single colony from liver(KS-1)and anal swab(KS-2)were selected for purification and culture.The isolates were identified by morphological observation,biochemical test,16S rRNA gene amplification together with phylogenetic group.The pathogenicity and drug resistance of the isolates were evaluated by virulence gene detection,pathogenicity test and drug sensitivity test.[Result]After inoculation,the lung,liver,heart blood,joint fluid and mesenteric lymph nodes of dead calves showed a consistent colony growth pattern,as did anal swab samples from healthy calves.The isolated strains were identified as Escherichia coli(E.coli)by the growth morphology of the colony on selective medium,the morphological features of Gram staining microscopy,the biochemical properties and the verification of E.coli 16S rRNA.Phylogenetic analysis showed that KS-1 belonged to group A and KS-2 to group B1.KS-1 contained 8 virulence-related genes(crl,papC,hlyE,eaeA,ompA,ompC,iucD and iutA),and KS-2 contained 3 virulence-related genes(crl,hlyE and ompF).The pathogenicity test results showed that following intraperitoneal injection of 1×108 CFU of the isolate,all mice in KS-1 group died within 16 h,however no mice in KS-2 group died.The results of drug sensitivity tests showed that KS-1 was sensitive to 17 drugs,including piperacillin/tazobactam,cefazolin,cefuroxime,cefuroxime,etc.,it was moderately sensitive to ampicillin/sulbactam and piperacillin,and resistant to ampicillin and cotrimoxazole.KS-2 was sensitive to piperacillin/tazobactam,cefotetan,imipenem,meropenem,amikacin and nitrofurantoin,moderately sensitive to tobramycin,and resistant to the other 14 drugs.[Conclusion]In this study,two calf-derived E.coli strains were isolated,of which KS-1 was more virulent and carried abundant virulence genes,it was sensitive to most commonly used antibiotics,and was resistant to ampicillin and sulfamethoxazole,while KS-2 carried few virulence genes and showed multi-drug resistance.关键词
犊牛/肠外致病性大肠杆菌/分离鉴定/毒力基因/耐药性Key words
calves/extraintestinal pathogenic Escherichia coli/isolation and identification/virulence genes/drug resistance分类
农业科技引用本文复制引用
史唯地,蒋建军,高盛杰,康立超,刘彩霞,寇丽君,吕双飞,任慧杰,钱瑞宣,马勋,王静..犊牛源肠外致病性大肠杆菌分离鉴定、致病性及耐药性分析[J].中国畜牧兽医,2023,50(12):5022-5031,10.基金项目
国家自然科学基金(32160834、32160833、32260895) （32160834、32160833、32260895）
