扬州某社区健康人源大肠杆菌bla_(CTX-M)的流行特征  

Characterization of bla_(CTX-M) in Escherichia coli isolates from healthy individuals in a Yangzhou community

作　　者：邵逸乔 梅彩月 蒋悦 卢恒帆 王振宇 刘梦月 焦新安[1,2] 王晶 SHAO Yi-qiao;MEI Cai-yue;JIANG Yue;LU Heng-fan;WANG Zhen-yu;LIU Meng-yue;JIAO Xin-an;WANG Jing(Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses,Yangzhou University,Yangzhou 225009,China;Key Laboratory of Prevention and Control of Biological Hazard Factors(Animal Origin)for Agrifood Safety and Quality,Ministry of Agriculture and Rural Affairs,Yangzhou University,Yangzhou 225009,China)

机构地区：[1]江苏省人兽共患病学重点实验室/江苏省动物重要疫病与人兽共患病防控协同创新中心,扬州大学,扬州225009 [2]农业农村部农产品质量安全生物性危害因子(动物源)控制重点实验室,扬州大学,扬州225009

出　　处：《中国人兽共患病学报》2023年第6期603-609,共7页Chinese Journal of Zoonoses

基　　金：江苏省重点研发计划(现代农业)(No.BE2021331);扬州大学大学生创新创业训练计划项目(No.X20210717)。

摘　　要：目的为调查扬州某社区健康人源大肠杆菌的耐药状况以及超广谱β-内酰胺酶基因bla_(CTX-M)的流行特征。方法2021年从扬州某社区健康人群中采集鼻拭子样品58份和粪便样品37份,通过麦康凯琼脂、PCR等方法进行大肠杆菌的分离和鉴定,采用琼脂稀释法或微量稀释法测定药物敏感性,通过PCR扩增和测序检测bla_(CTX-M)基因,同时对bla_(CTX-M)阳性大肠杆菌进行全基因组测序。结果从95份样品中分离获得35株大肠杆菌。大肠杆菌对四环素耐药率最高为35.3%,其次为氨苄西林(30.6%)和萘啶酸(27.8%),对头孢他啶、头孢噻肟、庆大霉素、链霉素、复方新诺明的耐药率在10%~20%,对氯霉素、氟苯尼考、环丙沙星、磷霉素耐药率均在10%以下。4株(11.4%)对头孢噻肟耐药的菌株携带bla_(CTX-M)-1G基因,包括bla_(CTX-M)-55(n=3)和bla_(CTX-M)-15(n=1),其中1株可将bla_(CTX-M)接合转移至大肠杆菌C600。在bla_(CTX-M)基因的上游均存在1个拷贝的插入序列ISEcp 1或被IS 26截断的ISEcp 1。结论bla_(CTX-M)基因在扬州某社区健康人源大肠杆菌携带率低,其传播可能与ISEcp 1有关。To investigate antibiotic resistance and characterize bla_(CTX-M) in Escherichia coli isolated from healthy individuals in a Yangzhou community,58 nasal swabs and 37 fecal samples were collected from healthy volunteers in 2021.E.coli was isolated and identified using MacConkey agar and PCR.Antimicrobial susceptibility was determined using the agar dilution or broth microdilution method.The presence of bla_(CTX-M) was screened by PCR and sequencing technology.The bla_(CTX-M)-positive E.coli isolates were analyzed by whole genome sequencing.A total of 35 E.coli isolates were obtained.The isolates had highest resistance to tetracycline(35.3%),followed by ampicillin(30.6%)and nalidixic acid(27.8%).The resistance rates to cefazolin,cefotaxime,gentamycin,streptomycin,and sulfamethoxazole/trimethoprim were between 10%and 20%.The resistance rates to chloramphenicol,florfenicol,ciprofloxacin,and fosfomycin were<10%.Four(11.4%)cefotaxime-resistant E.coli strains carried bla_(CTX-M),including bla_(CTX-M)-55(n=3)and bla_(CTX-M)-15(n=1),and one of which was able to transfer bla_(CTX-M) to E.coli C600 by conjugation.One copy of ISEcp 1 or an incomplete ISEcp 1 truncated by IS 26 was present upstream of bla_(CTX-M).In conclusion,a low prevalence of bla_(CTX-M) was demonstrated in E.coli isolates from healthy humans in this Yangzhou community.The dissemination of bla_(CTX-M) was shown to be associated with ISEcp 1.

关 键 词：大肠杆菌 人 bla_(CTX-M) 耐药性 

分 类 号：R378.2[医药卫生—病原生物学]