Clinical mastitis (CM) is an important production disease in dairy cows, but much of the knowledge required to effectively control CM is lacking, specifically in low-income countries where most farms are small and have specific dairy management, such as regular udder cleaning and practicing hand milking. Therefore, we conducted a 6-month-long cohort study to (a) estimate the incidence rate of clinical mastitis (IRCM) at the cow and quarter level, (b) identify risk factors for the occurrence of CM, (c) describe the etiology of CM, and (d) quantify antimicrobial susceptibility (AMS) against commonly used antimicrobial agents in S. aureus and non-aureus Staphylococcus spp. (NAS) in dairy farms in the Chattogram region of Bangladesh. On 24 farms, all cows were monitored for CM during a 6-month period. Cases of CM were identified by trained farmers and milk samples were collected aseptically before administering any antimicrobial therapy. In total, 1383 lactating cows were enrolled, which totaled 446 cow-years at risk. During the study period, 196 new cases of CM occurred, resulting in an estimated crude IRCM of 43.9 cases per 100 cow-years, though this varied substantially between farms. Among the tested CM quarter samples, Streptococci (22.9%) followed by non-aureus staphylococci (20.3%) were the most frequently isolated pathogens and resistance of S. aureus and NAS against penicillin (2 out of 3 and 27 out of 39 isolates, respectively) and oxacillin (2 out of 3 and 38 out of 39 isolates, respectively) was common. The IRCM was associated with a high milk yield, 28 to 90 days in milk, and a higher body condition score. Our results show that there is substantial room for udder health improvement on most farms.

中文翻译：

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孟加拉国 Chattogram 亚热带环境下奶牛临床乳腺炎的发病率、病因和危险因素

临床乳腺炎 (CM) 是奶牛的一种重要生产疾病，但缺乏有效控制 CM 所需的大部分知识，特别是在低收入国家，那里的大多数农场规模较小且有特定的奶牛管理，例如定期乳房清洁和练习手挤奶。因此，我们进行了一项为期 6 个月的队列研究，以 (a) 估计奶牛和季度水平的临床乳腺炎 (IRCM) 的发病率，(b) 确定 CM 发生的风险因素，(c) 描述CM 的病因，以及 (d) 量化对金黄色葡萄球菌和非金黄色葡萄球菌中常用抗菌药物的抗菌敏感性 (AMS)属 (NAS) 在孟加拉国 Chattogram 地区的奶牛场。在 24 个农场，所有奶牛在 6 个月的时间里都接受了 CM 监测。CM 病例由受过培训的农民确定，并在进行任何抗菌治疗之前无菌收集牛奶样品。总共招募了 1383 头泌乳奶牛，总共有 446 牛年处于危险之中。在研究期间，发生了 196 例新的 CM 病例，估计粗 IRCM 为每 100 牛年 43.9 例，尽管这在农场之间差异很大。在测试的 CM 四分之一样本中，链球菌 (22.9%) 其次是非金黄色葡萄球菌 (20.3%) 是最常分离的病原体和金黄色葡萄球菌的耐药性NAS 对青霉素（分别为 3 个分离物中的 2 个和 39 个分离物中的 27 个）和苯唑西林（分别为 3 个分离物中的 2 个和 39 个分离物中的 38 个）是常见的。IRCM 与高产奶量、28 至 90 天的牛奶以及更高的身体状况评分相关。我们的结果表明，大多数农场的乳房健康都有很大的改善空间。