甘肃省某奶牛场肠杆菌性乳房炎主要病原菌的分离鉴定与耐药性分析

为查明甘肃省某奶牛场发生临床型奶牛乳房炎的主要病原菌并选择治疗用敏感药物,随机无菌采集了6份临床型病牛乳样和1份大罐乳样,采用划线分离、菌落形态观察、革兰染色镜检、生化鉴定及16S rDNA序列分析等方法进行细菌分离鉴定,同时采用K-B法测定主要分离菌株对抗菌药物的敏感性。结果表明,从临床型乳房炎乳样中分离鉴定出大肠埃希菌、芽胞杆菌、凝固酶阴性葡萄球菌(腐生葡萄球菌)3种细菌,其中大肠埃希菌的分离率最高,为66.67%;从大罐奶样中也分离出大肠埃希菌。药敏试验结果表明,大肠埃希菌对氨苄青霉素、阿莫西林、头孢噻吩、杆菌肽、红霉素均存在不同程度的耐药,耐药率为29%~100%;对诺氟沙星、恩诺沙星、氟苯尼考、头孢哌酮等药物敏感。说明此次牛场临床型乳房炎的主要病原菌是大肠埃希菌、葡萄球菌和芽胞杆菌,而且分离的大肠埃希菌具有多重耐药性。根据检测分析结果,给奶牛场提出针对性的防控措施,临床型乳房炎的发病率下降,病情得以控制。

Isolation,Identification and Drug Resistance Analysis of Main Pathogens from a Farm of Dairy Cows with Mastitis in Gansu Province

A clinical type of cow mastitis occurred in one dairy farm of Gansu.In order to find out the main pathogens and select effective drugs for clinic treatment,six milk samples from sick cows and one sample from miltank were collected randomly.The plate culture method,colonial morphology observation,Gram staining and microscopy detection,biochemical identification and 16 S rDNA sequence analysis were used to isolate and identify the bacteria.At the same time,K-B method was used to measure the sensitivity of the main isolated bacteria to antibacterials.The results showed that,Escherichia coli ,Bacillus,coagulase neg-ative Staphylococcus (Staphylococcus saprophytic )were isolated and identified from the clinical mastitis milk samples.The isolation rate of E.coli was the highest,66.67%.E.coli was also isolated from milt-ank.Susceptibility test result showed that E.coli was resistant to some drugs in varying degrees,such as ampicillin,amoxicillin,cephalothin,bacitracin and erythromycin,and drug resistance rate from 29% to 100%,and had the higher susceptibility to norfloxacin,enrofloxacin,florfenicol,cefoperazone.According to the results,the main pathogen of the clinical mastitis is E.coli,and opportunistic pathogens of mixed in-fection were Staphylococcus and Bacillus.The isolated E.coli had strong multiple drug resistance.Ac-cording to the assay results,specific control measures were proposed to the dairy farm to help to control the infection and decrease the incidence of clinical mastitis.