奶牛源MRSA肠毒素基因、耐药基因及分子分型分析  

Analysis of Enterotoxin Genes, Resistance Genes and Molecular Typing of MRSA Isolated from Dairy Cow

作　　者：陈程[1] 万佳宏 王曈 常佳伟 王桂琴[1] Chen Cheng;Wan Jiahong;Wang Tong;Chang Jiawei;Wang Guiqin(College of Agriculture,Ningxia University,Yinchuan,750021)

机构地区：[1]宁夏大学农学院,银川750021

出　　处：《基因组学与应用生物学》2020年第3期1080-1088,共9页Genomics and Applied Biology

基　　金：国家自然科学基金项目(31360626)资助。

摘　　要：为了解宁夏地区奶牛源耐甲氧西林金黄色葡萄球菌的肠毒素基因和耐药基因分布及其分子流行病学特征,本研究通过聚合酶链式反应(polymerase chain reaction, PCR)技术对前期分离于宁夏地区的9株奶牛源耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA)进行了18种肠毒素基因和16种耐药基因的检测,同时采用脉冲场凝胶电泳(pulsed-field gel electrophoresis, PFGE)、正向重复序列(direct-repeat unit, dru)和辅助基因调节因子(accessory gene regulator, agr)分子分型技术对MRSA菌株进行分型研究。结果显示所有MRSA菌株均携带经典型肠毒素基因和新型肠毒素基因,共检出12种肠毒素基因,其中selk基因的检出率最高,达到了100%,未检出see、selj、selo、selp、ser和selu基因;11种耐药基因被检出,其中norA、gyrA、grlA和blaZ 4种基因的检出率均达到了100%,未检出tet (O)、optrA、Lin (A)、fexA和cfr基因。PFGE分型结果显示受试菌株间亲缘关系较近;dru分型检出dt11v和dt10a两种型,其中以dt11v(77.8%, 7/9)为主;agr分型主要为agr-Ⅰ型(88.9%, 8/9),agr-Ⅱ型仅有1株。研究表明宁夏地区奶牛源耐甲氧西林金黄色葡萄球菌(MRSA)中的肠毒素基因和耐药基因分布广泛,菌株间亲缘关系较近,agr-Ⅰ-dt11v为MRSA菌株中的流行基因型。这为以后宁夏地区奶牛源MRSA的产毒性、耐药性和分子流行病学特征的进一步研究提供理论依据。In order to investigate the distributions of enterotoxin genes and resistance genes and molecular epidemiological characteristics of methicillin-resistant Staphylococcus aureus isolated from dairy cow in Ningxia,in this study, 18 enterotoxin genes and 16 resistance genes were detected by using polymerase chain reaction method in 9 methicillin-resistant Staphylococcus aureus strains from dairy cow in Ningxia. Simultaneously, MRSA strains were typed by using pulsed-field gel electrophoresis, direct-repeat unit and accessory gene regulator typing.The results showed that all MRSA strains carried the classical enterotoxin genes and novel enterotoxin genes, and12 enterotoxin genes were detected. Among them, the detection rate of selk gene was the highest, reaching 100%,and no see, selj, selo, selp, ser, selu genes were detected. 11 resistance genes were detected. The detection rates of norA, gyrA, grlA and blaZ genes were the highest, reaching 100%. The tet(O), optrA, Lin(A), fexA and cfr genes were not detected. PFGE typing showed that the phylogenetic relationships of the strains were close. The dru-typing detected dt11 v and dt10 a, of which dt11 v(77.8%, 7/9) was predominant type. Agr-Ⅰtype(88.9%, 8/9) was the main agr type, and only 1 strain was agr-Ⅱtype. This study showed that the enterotoxin genes and resistance genes in methicillin-resistant Staphylococcus aureus isolated from dairy cow in Ningxia were widespread, and strains’ genetic relationship were close. Agr-Ⅰ-dt11 v is an epidemic genotype in MRSA strains. This provides a theoretical basis for further research on the toxicity, drug resistance and molecular epidemiological characteristics of MRSA of dairy cow in Ningxia.

关 键 词：MRSA 肠毒素基因 耐药基因 分子分型 

分 类 号：S823[农业科学—畜牧学]