奶牛乳腺炎无乳链球菌的分离鉴定与耐药性分析

Isolation, Identification and Drug Resistance Analysis of Streptococcus agalactiae Isolated from Dairy Cows

奶牛乳腺炎是奶牛养殖业的常见疾病,而无乳链球菌是乳腺炎的重要病原体之一。本试验从江苏和河北地区的规模化奶牛场中共收集67份乳腺炎奶样,经分离培养和鉴定,共分离出33株无乳链球菌。药敏试验表明:河北地区和江苏地区奶牛场的分离株对阿莫西林、头孢氨苄等β-内酰胺类药物以及恩诺沙星等喹诺酮类药物高度敏感,而对链霉素、庆大霉素、卡那霉素以及丁胺卡那等氨基糖苷类药物均表现出较高的耐药性。此外,河北地区分离株对四环素、多西环素这两种药物比较敏感,但在江苏地区无乳链球菌对这两种药物表现出了较强的耐药性,耐药率均高达74.1%。说明不同地区的无乳链球菌耐药情况有一定的差异。本研究结果可为临床上用抗生素预防和治疗乳腺炎提供参考。

Cow mastitis is a common disease in dairy cattle breeding industry,and Streptococcus agalactiae is one of the most important pathogens of mastitis.In this experiment,totally 67 milk samples of mastitis were collected from large-scale dairy farms in Jiangsu and Hebei.After isolation,cultivation and identification,33 S.agalactiae isolates were isolated.The drug susceptibility test of Streptococcus agalactiae showed that isolates from Hebei and Jiangsu were highly sensitive to β-lactams such as amoxicillin and cephalexin,and quinolones such as enrofloxacin.Aminoglycosides such as clindamycin,gentamycin,kanamycin,and amikacin showed high drug resistance.In addition,Streptococcus agalactiae in Jiangsu were sensitive to tetracyline and doxycycline.However,isolates in Jiangsu showed strong resistance to these drugs.The resistance rates were as high as 74.1%.It shows that there are certain differences in the drug resistance of Streptococcus agalactiae in different regions.The results of this study can provide reference for the clinical use of antibiotics to prevent and treat mastitis.