Abstract：
Adoption of a rational management in dairy farms would improve the milk quality and farmers\' income. In the current study, we aimed to describe bovine mastitis in 32 dairy herds, identify the main cow- and herd-associated risk factors, and analyze both epidemiological along with molecular characteristics of Staphylococcus aureus infecting udders. Based on Californian Mastitis Test and clinical examination, the prevalence of mastitis in cows was 52.25% (116/222), of which 6.3% was clinical mastitis and 45.94% was subclinical mastitis. Overall, 218 (24.54%) quarters suffered from mastitis, whose 29.81% (65/218) infected with S. aureus. Mastitis was lowest in mid-lactation with OR = 0.371 with 95% confidence interval (CI) of 0.141-0.976, and in cows separated from their calves (OR = 0.164, 95% CI 0.056-0.477) than suckler cows. Similar results were obtained from S. aureus related mastitis. To assess the genetic lineages of S. aureus isolates, we determined clonal complexes (CC) using DNA microarray hybridization profiles and performed spa typing. The strains were assigned to nine clonal complexes, and 19 spa types; with CC97 (44.77%), and CC22 (40.29%) were the most predominant lineages and t223 (40.29%), t7136 (10.44%), t359 (8.95%) and t267 (5.97%) were the most common spa types. A total of 88.05% (n = 59) isolates were resistant to at least one tested antibiotic while only 4.47% were multi-drug resistant strains. Higher rates of resistance were observed for penicillin (86.5%) and tetracycline (14.9%) respectively. Our results show the need for adoption of feasible mastitis program with special emphasis on sub-clinical mastitis and associated risk factors.
摘要：
在奶牛场采取合理的管理将提高牛奶质量和农民的收入。在目前的研究中,我们旨在描述32个奶牛群中的奶牛乳腺炎，确定与牛和牛群相关的主要危险因素，并分析了金黄色葡萄球菌感染乳房的流行病学和分子特征。基于加州乳腺炎测试和临床检查，奶牛乳腺炎患病率为52.25%(116/222),其中6.3%为临床乳腺炎，45.94%为亚临床乳腺炎。总的来说,218个季度（24.54%）患有乳腺炎，其29.81％（65/218）感染金黄色葡萄球菌。哺乳期中期乳腺炎最低，OR=0.371，95％置信区间（CI）为0.141-0.976，与小牛分离的母牛（OR=0.164，95％CI0.056-0.477）比乳牛。从金黄色葡萄球菌相关的乳腺炎获得了类似的结果。为了评估金黄色葡萄球菌分离株的遗传谱系，我们使用DNA微阵列杂交谱测定了克隆复合物(CC)并进行了spa分型.这些菌株被分配到9个克隆复合物中，和19种水疗类型；CC97（44.77%），CC22(40.29%)是最主要的谱系，t223(40.29%)是最主要的谱系，t7136（10.44%），t359（8.95％）和t267（5.97％）是最常见的水疗类型。共有88.05％（n=59）的分离株对至少一种测试的抗生素具有抗性，而只有4.47％是多重耐药菌株。青霉素(86.5%)和四环素(14.9%)耐药率较高。我们的结果表明，需要采用可行的乳腺炎计划，特别强调亚临床乳腺炎和相关的危险因素。
