摘要
旨在从分子水平阐明河北地区鸡源大肠杆菌CTX-M型超广谱β-内酰胺酶(ESBLs)基因流行特征,探究大肠杆菌耐药性传播途径,为制定科学的防控措施奠定基础。从河北地区病鸡肝中分离大肠杆菌,通过选择性培养基培养特性观察、细菌生化试验、16S rRNA方法鉴定分离菌株;采用K-B法测定细菌的药物敏感性;通过PCR技术检测第3代头孢菌素耐药菌株中CTX-M基因(blaCTX-M-1、blaCTX-M-2、blaCTX-M-8和blaCTX-M-9)和整合子整合酶基因(Int1、Int2和Int3)的流行情况,比对基因序列,分析携带CTX-M基因亚型的情况。参照McMLST网站数据库提供的7对管家基因序列进行MLST分型,探索不同ST型菌株中CTX-M基因亚型的流行情况。经分离鉴定试验,共检测出56株大肠杆菌,其中41株(73.21%)大肠杆菌对第3代头孢菌素类抗生素耐药,且对碳青霉烯类抗生素呈高度敏感。第3代头孢菌素耐药菌株中携带blaCTX-M-9(48.78%)、blaCTX-M-1(43.90%)和blaCTX-M-8(24.39%),未检出blaCTX-M-2。从CTX-M-9群共检出CTX-M-65(n=10)、CTX-M-14 (n=8)和CTX-M-27 (n=2)这3种基因亚型;CTX-M-55 (n=15)型在CTX-M-1群中的检出率最高,其次为CTX-M-123(n=2)和CTX-M-64(n=1);36株携带blaCTX-M大肠杆菌同时携带Ⅰ型整合子的Int1基因。MLST分型结果表明,36株携带CTX-M基因的大肠杆菌共有16种ST型,优势流行型为ST85 (n=6)和ST243 (n=6)。由此可见,河北地区鸡源大肠杆菌对第3代头孢菌素的耐药率较高,对极少数的抗生素呈高度敏感,且呈现多重耐药型,第3代头孢菌素耐药菌株普遍携带CTX-M型耐药基因,以CTX-M-55、CTX-M-65、CTX-M-14型为主。本研究结果表明,河北地区鸡源大肠杆菌普遍具有耐药性,有丰富的耐药谱型,同时多种耐药基因可存在于同一株细菌中,不同耐药基因的ST型归属特性存在差异。
Based on molecular level,this test is to clarify prevalence of blaCTX-Min extended-spectrum β-lactamases(ESBLs)-producing Escherichia coli of chicken origin in Hebei,explore the route of antibiotic resistance transmission in E.coli,and lay the foundation for formulating scientific prevention and control measures of the bacteria.E.coli was isolated from livers of sick chickens in Hebei Province. The strains were identified by observation of growth characteristics on selective medium,bacterial biochemical test and 16 S r RNA analysis.Susceptibility of bacteria was determined using K-B technique,and genes related to the resistance to the third generation of cephalosporins and their prevalence,CTX-M gene(blaCTX-M-1,blaCTX-M-2,blaCTX-M-8 and blaCTX-M-9)and integrase gene(Int1,Int2 and Int3)prevalence were detected by PCR,matching gene sequence,analysis with CTX-M gene subtype.Seven pairs of housekeeping gene sequences provided by Mc MLST website database were used to MLST,and different ST type strains of CTX-M gene subtypes prevalence was explored.A total of 56 strains of E.coli were detected by isolation and identification test,of which 41 strains(73.21%) were resistant to thirdgeneration cephalosporin antibiotics and highly sensitive to carbopenems antibiotics.It has been found that the strains resistant to the third generation of cephalosporins drug carried blaCTX-M-9(48.78%),blaCTX-M-1(43.90%) and blaCTX-M-8(24.39%),but not blaCTX-M-2.The three subtypes of CTX-M-65(n =10),CTX-M-14(n=8) and CTX-M-27(n=2) were detected in CTX-M-9 group.The detection rate of type CTX-M-55(n=15)was the highest in the CTX-M-1 group,followed by CTX-M-123(n=2) and CTX-M-64(n=1).Thirty-six strains of E.coli blaCTX-Mcarried Int1 gene in type I integron.MLST typing results showed that 36 strains of E.coli carrying CTX-M gene had 16 ST types,and the dominant epidemic types were ST85(n=6) and ST243(n=6).Thus,the E.coli strains sourced of chickens in the Hebei area had a high resistant rate to the third generation of cephalosporins,and was hi
作者
张立伟
朱阵
刘洋
郝贺
刘冠慧
张永英
石玉祥
ZHANG Li-wei;ZHU Zhen;LIU Yang;HAO He;LIU Guan-hui;ZHANG Yong-ying;SHI Yu-xiang(Hebei University of Engineering,Handan 056000,China)
出处
《中国兽医科学》
CAS
CSCD
北大核心
2021年第5期608-620,共13页
Chinese Veterinary Science
基金
河北省研究生创新资助项目(CXZZSS2020078)
河北省重点研发计划项目(18226620D)
河北省自然科学基金项目(C2019402114)
传染病预防控制国家重点实验室项目(2018SKLID308)
河北省科技重大专项(19046637Z)。
