青海省某奶牛场顽固性乳房炎主要病原菌的分离鉴定与耐药性研究

Isolation,Identification and Drug-resistance of Main Pathogens from Milk of Dairy Cows with Intractable Mastitis in Qinghai Province

为了明确青海省某奶牛场顽固性乳房炎的病原菌,并制定有效的防控措施,本试验采用细菌分离、16SrDNA序列分析、细菌基因分型等方法对病牛乳样中的病原菌进行分离鉴定,并进行17种药物的敏感性试验。试验从15份乳样中分离到10株金黄色葡萄球菌、1株表皮葡萄球菌和2株化脓隐秘杆菌,其中10株金黄色葡萄球菌均为荚膜多糖5型分离株;所分离金黄色葡萄球菌对青霉素G、红霉素、头孢氨苄和呋喃妥因耐药率分别为100%、90%、10%和10%;表皮葡萄球菌对青霉素G、复方新诺明和甲氧苄氨嘧啶耐药,而对其他14种抗菌药物敏感;化脓隐秘杆菌对四环素和甲氧苄氨嘧啶耐药,对强力霉素和复方新诺明中度敏感,对其他13种抗菌药物敏感。该牛场顽固性乳房炎是多种病原菌混合感染所致,但以荚膜多糖5型金黄色葡萄球菌为主。不同的病原菌的药物敏感性不同,故而治疗困难,建议使用恩诺沙星治疗病牛并加强隐性乳房炎的筛查与防治,病情得到控制。

In order to determine the main pathogens from milk of dairy cows with intractable mastitis in Qinghai province,and to develop effective prevention and control measures,the pathogens were isolated and identificated by16 SrDNA sequence analysis and genotyping.And then we performed a sensitivity test of17 kinds of antimicrobials.The results showed 13 bacterial isolates were isolated from 15 milk samples,including ten isolates of Staphylococcus aureus,one isolate of Staphylococcus epidermidis and two isolates of Trueperella pyogenes.All of the Staphylococcus aureus were type 5of capsular polysaccharide.Staphylo coccusaureuswas resistant to penicillin G（100%）,erythromycin（90%）,cephalexin（10%）and nitrofurantoin（10%）.Staphylococcus epidermidis was resistant to penicillin G,cotrimoxazole and trimethoprim while sensitive to other 14 kinds of antimicrobials.Trueperella pyogenes was resistant to tetracycline and trimethoprim strongly,and resistant to doxycycline and cotrimoxazole moderately,on the contrary,they were sensitive to the remaining 13 kinds of antimicrobials.In conclusion,these intractable mastitis was caused by mixed infections of many pathogens,and Staphylococcus aureus of capsular polysaccharide type 5was the main pathogens.It was difficult to treat different pathogens with the different levels of drug-resistance.Finally we recommended using enrofloxacin to control this condition.