辽宁地区奶牛乳房炎细菌性病原分离鉴定及大肠杆菌药敏试验

为了掌握辽宁地区奶牛乳房炎主要细菌性病原种类及致奶牛乳房炎大肠杆菌药物敏感性特征，本研究选取辽宁地区某大型奶牛场75头临床表现为乳房炎的奶样进行细菌培养与分离，通过生化方法对分离到的细菌进行鉴定，并对分离到的奶牛源大肠杆菌进行体外药物敏感性试验研究。结果发现，该场奶牛乳房炎细菌性病原主要为大肠杆菌、葡萄球菌和链球菌，其检出率分别为58.7%、64.0%和54.7%，存在二重感染和三重感染等混合感染的情况。大肠杆菌药物敏感性试验结果表明，该场分离株对磺胺类药物（耐药率>85%）及氯霉素类药物（耐药率>30%）耐药性较高，对氨苄西林（9.5%）、环丙沙星（9.5%）、头孢噻呋（7.1%）和氧氟沙星（4.8%）比较敏感。上述研究结果为该地区奶牛乳房炎的防制提供可靠的理论依据。

Isolation and Identification of Pathogenic Bacteria Causing Dairy Cow Mastitis in Liaoning and Drug Sensibility Test of Pathogenic E.coli

In order to understand the main bacterial pathogen species causing dairy cow mastitis in Liaoning, as well as the characteristics of drug sensitivity of the pathogenic E.coli,the milk samples from 75 dairy cows with clinical manifestations for mastitis in certain large-scale dairy farm in Liaoning were collected.The bacteria in milk were cultured and isolated with biochemical methods and in vitro drug sensitivity tests were processed with the isolated E.coli strains.The results showed that the main bacterial pathogen for dairy cow mastitis were E.coli（separation rate 58.7%),S.aureus（64.0%）and S.agalactiae（54.7%),and multiple infection including double and triple infection were identified.The drug sensitivity tests on the isolated E.coli indicated that the E.coli isolates were highly resistant to sulfonamides（resistance rate>85%）and chloramphenicol（resistance rate>30%),and they were relatively low resistant to ampicillin（9.5%),ciprofloxacin（9.5%),ceftiofur（7.1%）and ofloxacin（4.8%).The results was able to provide reliable theoretical basis for prevention and control of dairy cow mastitis in Liaoning area.