Mastitis is a cow disease usually signalized by irritation, swelling, and soreness of the udder. It is characterized by physical, chemical, and biological changes in the udder and milk. The aim of this study was to detect and characterize pathogens causing subclinical mastitis (SCM) from the milk of dairy cows of small-scale farmers through culture and molecular techniques. Milk was collected from 32 cows belonging to 8 small-scale farmers around Harrismith District, South Africa. The results showed that screening of SCM by California mastitis test and somatic cell counts (SCC) was 21.87 and 25%, respectively. Culture methods revealed the presence of Staphylococcus aureus at 93% followed by Streptococci spp. and Escherichia coli at 36.4 and 13.3%, respectively. The PCR could only detect E. coli, while single-molecule real-time sequencing showed a total of 2 phyla, 5 families, 7 genera, and 131 species. Clostridiaceae was the most abundant family, while Romboutsia was the most abundant genus followed by Turicibacter spp. The present study has documented the occurrence of SCM causing pathogens in milk collected from cows of small-scale farmers in Harrismith, indicating that SCM may be present at higher levels than expected.

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应用培养、PCR 和 PacBio 测序测定小农场亚临床乳腺炎奶牛的牛奶微生物组成

乳腺炎是一种奶牛疾病，通常表现为乳房发炎、肿胀和疼痛。它的特点是乳房和乳汁的物理、化学和生物变化。本研究的目的是通过培养和分子技术从小农奶牛的牛奶中检测和表征引起亚临床乳腺炎 (SCM) 的病原体。牛奶是从南非哈里史密斯区周围 8 个小农户的 32 头奶牛身上采集的。结果显示，加州乳腺炎试验和体细胞计数（SCC）对SCM的筛查分别为21.87%和25%。培养方法揭示了金黄色葡萄球菌93% 紧随其后链球菌spp. 和大肠杆菌分别为 36.4% 和 13.3%。PCR只能检测大肠杆菌，而单分子实时测序显示共有2门5科7属131种。梭菌科是最丰富的科，而朗布西亚是最丰富的属，其次是螺旋杆菌spp. 本研究记录了从 Harrismith 小农户的奶牛采集的牛奶中引起 SCM 病原体的发生，表明 SCM 的存在水平可能高于预期。