Abstract:
Bovine mastitis is an important and costly disease to dairy cattle. Diagnostic methods usually performed in Brazil are somatic cell counts (SCC) and milk microbiology. Low bacteria shedding in milk implies no colony growth in microbiological tests and false negative results. Streptococcus agalactiae and Staphylococcus aureus are principal pathogens of mixed mastitis. However, S. agalactiae has a higher bacterial release from the mammary gland than S. aureus, affecting microbiological sensitivity to diagnose S. aureus. This study aimed to estimate the SCC and total bacterial count (TBC) from cows according to pathogen isolated in milk and to evaluate variation in S. aureus diagnosis by a microbiological test during S. agalactiae treatment, which is called blitz therapy. Both S. agalactiae and S. aureus presented high SCC means, although S. agalactiae showed shedding of bacteria 2.3 times greater than S. aureus. Microbiological sensitivity to S. aureus increased for 5 months during S. agalactiae treatment. The prevalence of S. agalactiae fell after 5 months of therapeutic procedures. The prevalence of S. aureus increased to 39.0. The results showed that due to high sensitivity, the polymerase chain reaction (PCR) could be used at the beginning of blitz therapy with the goal of S. agalactiae eradication from the dairy herd.
摘要:
牛乳腺炎是奶牛的重要且昂贵的疾病。通常在巴西进行的诊断方法是体细胞计数(SCC)和牛奶微生物学。牛奶中细菌的低脱落意味着微生物测试中没有菌落生长和假阴性结果。无乳链球菌和金黄色葡萄球菌是混合乳腺炎的主要病原体。然而,无乳链球菌从乳腺中的细菌释放量比金黄色葡萄球菌高,影响诊断金黄色葡萄球菌的微生物敏感性。本研究旨在根据乳中分离的病原体估算奶牛的SCC和总细菌计数(TBC),并通过无乳链球菌治疗期间的微生物学试验评估金黄色葡萄球菌诊断的变化。这就是所谓的闪电战疗法。无乳链球菌和金黄色葡萄球菌均表现出高SCC手段,尽管无乳链球菌的细菌脱落量是金黄色葡萄球菌的2.3倍。无乳链球菌治疗期间,对金黄色葡萄球菌的微生物敏感性增加了5个月。无乳链球菌的患病率在5个月的治疗程序后下降。金黄色葡萄球菌的患病率增加到39.0。结果表明,由于灵敏度高,聚合酶链反应(PCR)可以在突击治疗开始时使用,目的是从乳牛群中根除无乳链球菌。