一株牛源乡间布丘菌的分离鉴定及耐药性研究

Isolation,Identification and Drug Resistance Analysis of a Bovine Buttiauxella agrestis

为了解奶牛乳房炎病原微生物的生物学特性及其耐药性,本研究从奶牛乳房炎乳中分离到的一株革兰氏阴性菌,命名为HLJ-36,对其进行形态特征、生化鉴定、分子生物学鉴定、小鼠致病性试验及药敏试验。生化试验结果显示,木糖、ONPG、柠檬酸盐等反应呈阳性,氧化酶、吲哚、尿素酶等反应呈阴性。理化特性与分子生物学试验结果均显示,分离株与乡间布丘菌特征相符,与人源乡间布丘菌肠道分离株(GenBank登录号:NR_041968.1)同源性最高,达99%。小鼠致病性试验结果显示,试验组小鼠72h内未发生死亡,表明其致病性较弱。药敏试验结果显示,该菌对头孢噻呋、阿奇霉素、环丙沙星等耐药,对头孢西丁、美罗培南、氯霉素、阿莫西林—克拉维酸、庆大霉素敏感。结果表明,乡间布丘菌可能是引起奶牛乳房炎的一种病原菌,并有一定程度的耐药性,由于该菌与人源乡间布丘菌肠道分离株(GenBank登录号:NR_041968.1)同源性最高,有通过乳及乳制品传播给人类的可能,本试验具有一定的公共卫生学意义。

To understand the biological characteristics and resistance of pathogenic microorganisms of dairy cows with mastitis,agram-negative bacterium,named HLJ-36,was isolated from dairy cow＇s mastitis milk.Morphological characteristics,biochemical identification,molecular biological identification,mouse pathogenicity test and drug susceptibility test were performed.Biochemical test results showed that xylose,ONPG,citrate and so on were positive;Oxidase,sputum,urease and so on were negative.The physicochemical characteristics and molecular biological test results showed that the isolate was consistent with the characteristics of Buttiauxella agrestis,and had the highest homology with human Buttiauxella agrestis（GenBank accession No.：NR_041968.1）isolated from intestine,reaching 99%.The pathogenicity test in mice showed that mice in the experimental group did not die within 72 hours,indicating that the isolate was less pathogenic.Drug susceptibility test results showed that the bacteria were resistant to ceftiofur,azithromycin,ciprofloxacin,etc.,and sensitive to cefoxitin,meropenem,chloramphenicol,amoxicillin-clavulanic acid,and gentamicin.The results showed that Buttiauxella agrestis might be a pathogen causing dairy cow mastitis and had a certain degree of drug resistance,due to the highest homology of this strain and human Buttiauxella agrestis（GenBank accession No.：NR_041968.1）,there was a possibility of transmission to humans through milk and dairy products,which had certainpublic health significance.