[目的]调查广东地区畜禽源大肠杆菌的耐药特征与流行情况，为动物源大肠杆菌耐药性防控提供参考。[方法]对2019年从广东地区10个不同生产用途养殖场采集饲料、饮水和健康动物的肛/泄殖腔拭子等样品进行大肠杆菌分离鉴定、药敏试验、耐药基因和插入序列共同区(insertion sequence common region，ISCR)检测及种族系统进化分析。[结果]共分离获得416株大肠杆菌，其中种猪源78株、肉猪源77株、蛋鸡源122株、肉鸡源139株。菌株呈现多重耐药特点，不同动物源大肠杆菌中，肉鸡源大肠杆菌耐药率最高。79。6％(331/416)的菌株对3种或3种以上药物产生耐药，最多可对13种药物耐药，共组成156种耐药图谱，耐药谱以复方新诺明/氟苯尼考/多西环素/阿莫西林/氨苄西林居多，占比为11。1％。耐药基因以floR基因检出率最高，为50。0％;其次是sul2和sul3基因，检出率分别为44。2％和42。5％。与替加环素、黏菌素耐药表型相关的耐药基因tet(X3)、tet(X4)和mer-1检出率均低于10％。插入序列共同区ISCR1、ISCR2和ISCR3的检出率分别为14。4％、10。8％和10。6％。酰胺醇类、磺胺类和β-内酰胺类耐药基因与耐药菌株的符合率在60％以上。耐药基因cmlA、tetA、qnrS、blacTX-M-9G与ISCR1的共存有统计学意义(P＜0。05);tet(X4)、sul2基因与ISCR2的共存有统计学意义(P＜0。05);tet(X4)、sul3、qnrS、blaSHV基因与ISCR3的共存有统计学意义(P＜0。05)。不同动物源大肠杆菌以A群分布为主，ISCR相关移动元件阳性菌主要分布在A群。[结论]广东部分地区动物源大肠杆菌呈现多重耐药现状，携带多种耐药基因及可移动元件ISCR。本研究结果可为掌握广东地区动物源细菌耐药特征及耐药基因的流行情况提供依据。
Drug Resistance and Prevalence of Escherichia coli Isolated from Livestock and Poultry in Areas of Guangdong
[Objective]The aim of this experiment was to investigate the prevalence and drug resistance of Escherichia coli(E.coli)from livestock and poultry in some areas of Guangdong,and provide reference for drug resistance prevention and control of E.coli derived from animals.[Method]Samples of feed,drinking water and anal(cloaca)swabs of healthy animals collected from 10 farms in some areas of Guangdong in 2019 were subjected to E.coli isolation and identification,drug sensitivity test,detection of drug resistance genes and insertion sequence common region(ISCR),as well as ethnic phylogenetic analysis.[Result]A total of 416 E.coli strains were isolated,including 78 strains from breeding pigs,77 strains from broilers,122 strains from laying hens and 139 strains from broilers.These strains showed the characteristics of multiple drug resistance,and the drug resistance rate of E.coli from broilers was the highest among different animal sources.79.6％(331/416)strains were resistant to 3 or more drugs,up to 13 drugs,and a total of 156 drug resistance profiles were formed.The main resistance profiles was sulfamethoxazole-trimethoprim/florfenicol/doxycycline/amoxicillin/ampicillin,accounting for 11.1％.floR gene showed the highest detection rate of 50.0％,followed by sul2 and sul3 genes,which were 44.2％and 42.5％,respectively.The detection rates of tet(X3),tet(X4)and mcr-1 genes associated with tigecycline and colistin resistance phenotypes were all lower than 10％.Insert sequence common region(ISCR)elements for ISCR1,ISCR2 and ISCR3 were present in 14.4％,10.8％and 10.6％isolates,respectively.The coincidence rate of phenicols,sulfonamides and β-lactam resistance genes with drug-resistant strains was more than 60％,respectively.The coexistence of drug resistance genes cmlA,tetA,qnrS,blaCTx-M-9G with ISCR1,tet(X4),sul2 with ISCR2,and tet(X4),sul3,qnrS,blaSHV with ISCR3,were statistically significant(P＜0.05),respectively.E.coli from different animals and ISCR-related mobile element-positive bacteria were both mainly distributed in phylogenetic group A.[Conclusion]E.coli isolates from animals in some areas of Guangdong presented multiple drug resistance,and carried multiple drug resistance genes,as well as mobile elements ISCR.These results provided reference for understanding the drug resistance characteristics and prevalence of resistant genes in animal-derived bacteria in Guangdong province.
Escherichia colilivestock and poultrydrug resistanceresistance genes
万方数据
维普
