猪源CTX-M型超广谱β-内酰胺酶阳性大肠杆菌耐药基因的流行性分析  

Investigation on the prevalence of drug resistant genes of the CTX-M type extended-spectrumβ-lactamases positive Escherichia coli strains isolated from pigs

作　　者：杨守深[1,2] 江妤丹 林敏 王佳慧[1] 曾晓菲 邱敏华 吴谦 陈薇瑾 蔡绍莉 黄翠琴 YANG Shou-shen;JIANG Yu-dan;LIN Min;WANG Jia-hui;ZENG Xiao-fei;QIU Min-hua;WU Qian;CHEN Wei-jin;CAI Shao-li;HUANG Cui-qin(College of Life Sciences,Longyan University,Longyan 364012,China;Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology,Longyan 364012,China)

机构地区：[1]龙岩学院生命科学学院,福建龙岩364012 [2]福建省家畜疫病防治与生物技术重点实验室,福建龙岩364012

出　　处：《中国预防兽医学报》2021年第5期552-557,共6页Chinese Journal of Preventive Veterinary Medicine

基　　金：龙岩市奇迈科技创新基金项目(2017QM0203);福建省自然科学基金项目(2018J01459);大学生创新创业训练计划项目(201911312012)。

摘　　要：为了解福建地区猪源CTX-M阳性大肠杆菌耐药性、耐药基因流行情况以及耐药质粒特征,本研究采用琼脂二倍稀释法测定福建地区分离的67株猪源CTX-M型超广谱β-内酰胺酶阳性大肠杆菌对13种抗菌药物的敏感性,通过PCR检测其重要的耐药基因;通过供体菌与受体菌(C600)的接合转移试验,检测携带CTX-M耐药基因耐药质粒的水平转移情况,并测定接合子的药物敏感性变化以及耐药质粒的复制子类型。结果显示,分离菌株对头孢噻呋(100%)、头孢噻肟(100%)和四环素(94.0%,63/67)耐药性较高,对阿米卡星相对敏感,耐药菌株仅占7.5%(5/67)。耐药基因检测结果显示,53.7%(36/67)的分离株携带3个以上耐药基因,黏菌素耐药基因mcr-1(49.3%,33/67)和氟苯尼考耐药基因floR(37.3%,25/67)的检出率较高,氟喹诺酮类耐药基因aac(6')-Ib-cr和oqxAB、四环素类耐药基因tetA、酰胺醇类耐药基因cmlA和磷霉素耐药基因fosA3的检出率在10.4%~19.4%,氨基糖苷类耐药基因rmtB(4.5%,3/67)的检出率最低;其中以CTX-M+mcr-1+floR耐药基因的组成模式流行为主,检出率为25.4%(17/67)。通过接合转移试验共获得21株接合子,与受体菌C600相比,其对受试药物,如头孢噻呋、头孢噻肟和庆大霉素等的最小抑菌浓度(MIC)提高了2~32倍。复制子分型结果显示17株分离菌分型成功,4株分离菌未能分型,其中以IncF型质粒为主。福建地区猪源CTX-M阳性大肠杆菌对抗菌药物呈较为严重的耐药性,耐药基因的携带率普遍较高且以mcr-1和floR基因流行为主,耐药质粒以IncF型为主。本研究为福建地区猪源大肠杆菌耐药性的风险评估与抗菌药的合理应用提供科学依据。In order to understand the drug resistance,prevalence of drug resistance genes and the characteristics of drug resistant plasmids of CTX-M positive Escherichia coli isolates,a total of 67 CTX-M-positive E.coli isolates from pigs in Fujian province were tested for antimicrobial susceptibility to 13 antimicrobial agents by an agar dilution method,followed by an analysis of important drug resistant genes by PCR.The horizontal transfer of drug-resistant plasmids carrying CTX-M gene was studied by coculture of donor and recipient bacterial strains(C600),and changes in drug sensitivity and the replicon types were determined.The isolates showed high resistance rate to ceftiofur(100%),cefotaxime(100%)and tetracycline(94.0%,63/67),and were relatively sensitive to amikacin(7.5%,5/67).The results of drug resistance gene detection showed that 53.7%(36/67)of the isolates carried more than three resistance genes.The detection rates of the colistin resistance gene mcr-1(49.3%,33/67)and the florfenicol resistance gene floR(37.3%,25/67)were relatively high,while the other resistance genes of the fluoroquinolones,tetracyclines,amphenicols,phosphomycin and aminoglycosides were detected among 10.4%to 19.4%,such as aac(6')-Ib-cr,oqxAB,tetA,cmlA and fosA3,and the rmtB(4.5%,3/67)was the lowest.The coexistence of CTX-M+mcr-1+floR genes was the dominant combination(25.4%,17/67).Twenty-one transconjugants were successfully obtained by conjugation experiments.Com pared with the recipient strain C600,the transconjugants showed 2-to 32-fold increases in the Minimal inhibition concentrations(MICs).The results of replicon typing showed that 17 strains were successfully typed while 4 strains were not,and the IncF type was the most prevalent.In conclusion,the CTX-M-positive E.coli isolates from Fujian province showed high resistance to antibiotics,and the prevalences of resistance genes were generally high.The mcr-1 and floR genes were the most prevalent and the resistance plasmids were mainly IncF type.This study provides a scientific basis for

关 键 词：耐药基因 复制子分型 流行特征 黏菌素 

分 类 号：S852.61[农业科学—基础兽医学]