动物源大肠杆菌整合子携带氨基糖苷类耐药基因盒的研究  

Study on gene cassettes in integrons for aminoglycosides resistance among E.coli isolates from animals

作　　者：林居纯[1] 曹三杰[1] 张辉建[1] 钟青卿[1] 魏峰[1] 文心田[1] 

机构地区：[1]四川农业大学国家级动物类实验教学示范中心,四川雅安625014

出　　处：《中国兽医学报》2011年第11期1587-1590,共4页Chinese Journal of Veterinary Science

基　　金：四川省优势产业发展急需紧缺专业博士后项目(2007CX01);四川省教育厅科研项目(2010ZY04)

摘　　要：收集540株不同动物源大肠杆菌,采用微量肉汤稀释法检测其对22种药物的耐药性;利用多重PCR方法检测菌株携带3型整合子的情况;采用χ2检验分析1型整合子阳性菌及阴性菌的耐药性;采用PCR-DNA测序法对整合子阳性菌株携带的氨基糖苷类耐药基因盒进行分析。结果显示,540株菌对链霉素等20种药物耐药率超过37%,全部菌株均呈多重耐药;1型整合子检出率为86.48%,未检出2及3型整合子;整合子阳性菌株对头孢唑啉等13种药物耐药率显著高于整合子阴性菌;随机选择的67株1型整合子阳性菌株中,有92.54%菌株携带有编码氨基糖苷核苷转移酶和乙酰转移酶基因(aadA2、aadA5、aadA22、aacA4),共有5种类型基因盒,其中以介导对甲氧苄啶、链霉素和大观霉素耐药的dfrA17+aadA5组合最为常见;在2株菌中分别发现介导对阿米卡星、氯霉素及甲氧嘧啶耐药的aacA4+catB3+dfrA1组合,和介导链霉素、大观霉素耐药的aadA22基因盒,是在四川分离菌中首次发现这2种基因盒。结果表明,1型整合子广泛存在于大肠杆菌临床菌株中,大肠杆菌耐药性与整合子相关,菌株中广泛携带氨基糖苷类及甲氧苄胺嘧啶耐药基因盒。A total of 540 E. coli isolates from animals were collected, the antimierobial resistance was determined by using the broth microdilution method;3 classes integrons among isolates were examined by multiple PCR;The antimicrobial resistance between intIl-positive strains and intIl-negative strains was analyzed by X2 method;PCR-DNA sequencing was used to identify the gene cassettes for aminoglyeoside resistance in integrons of intIl-positive strains. To 20 agents, including streptomycin, the resistant rates of 540 isolates were above 37 ~, all isolates dis- played multiple resistance^intI1 was detected in 86. 480//oo of the isolates,neither intI2 nor intI3 was detected in the study;The resistant rates of intll-positive strains to 13 agents tested were remarkably higher than that of intIl-neg- ative strains;92.54% of 67 strains selected randomly carried genes encoding resistance to aminoglyeosides（aadA2, aadA5,aadA22,aacA4）, 5 different gene cassettes were found. The most common array of cassettes was dfrA17 ＋ aadA5 conferring resistance to streptomycin/spectinomycin and to trimethoprim;Both aacA4＋catB3＋dfrA1 conferring resistance to amikacin, chloramphenicol, trimethoprim, and aadA22 conferring resistance to streptomycin/ speetinomycin, were first observed in 2 strains from Sichuan province. Class Lintegron was extensively distributed in E. coli isolates, the resistance was strongly correlated with integron,gene cassettes in integrons for aminoglyeosides and trimethoprimn resistance were extensively carried in E. coli isolates.

关 键 词：大肠杆菌 氨基糖苷类 耐药 整合子-基因盒 

分 类 号：S852.61[农业科学—基础兽医学]