Kaewkod Thida, Cheepchirasuk Nitsanat, Suriyaprom Sureeporn, Suriyasathaporn Witaya, Chitov Thararat, Panya Aussara, Tragoolpua Yingmanee
Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.
Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand.
Sci Rep. 2025 Jul 1;15(1):22416. doi: 10.1038/s41598-025-05355-9.
Bovine mastitis poses significant economic challenges for dairy farms globally. Metabolites from lactic acid bacteria (LAB) offer promising alternative substances for preventing bovine mastitis. This study demonstrated the inhibitory activity of metabolite production from seven LAB isolates in the supernatant medium. Four isolates, namely Lactiplantibacillus plantarum TISTR 2070, Lacticaseibacillus casei TISTR 1340, Enterococcus faecalis TCAN02, and Lactiplantibacillus plantarum AD73, exhibited antibacterial activity against bacterial pathogens causing mastitis, including Staphylococcus haemolyticus, Staphylococcus capitis subsp. ureolyticus, Streptococcus agalactiae O4, Streptococcus dysgalactiae, and Streptococcus uberis. The minimum inhibitory concentration (MIC) values ranged from 6.25 to 25 mg/mL, with minimum bactericidal concentration (MBC) values of 12.5 to 25 mg/mL. Furthermore, analysis of the physical and chemical properties revealed active metabolites in LAB supernatants, particularly lactic acid that was detected in all samples. Additionally, this study presents novel findings on infection of CPAE bovine endothelial cells in vitro by mastitis bacterial pathogens and demonstrating cytopathic effects such as vacuolation, magalocytosis, and cytotoxicity after bacterial infection on the bovine endothelial cells. Moreover, metabolites from LAB supernatant exhibited a protective effect against bacterial colonization and infection of bacterial pathogens causing mastitis on CPAE bovine endothelial cells and leading to increase cell viability. The results of this study suggest that metabolites from LAB samples exert potential candidates as alternative therapeutic agents for bovine mastitis.
牛乳腺炎给全球奶牛场带来了重大经济挑战。乳酸菌（LAB）产生的代谢产物为预防牛乳腺炎提供了有前景的替代物质。本研究证明了7株LAB分离株在上清培养基中产生的代谢产物的抑制活性。4株分离株，即植物乳杆菌TISTR 2070、干酪乳杆菌TISTR 1340、粪肠球菌TCAN02和植物乳杆菌AD73，对引起乳腺炎的细菌病原体具有抗菌活性，包括溶血葡萄球菌、解脲亚种头状葡萄球菌、无乳链球菌O4、停乳链球菌和乳房链球菌。最低抑菌浓度（MIC）值范围为6.25至25mg/mL，最低杀菌浓度（MBC）值为12.5至25mg/mL。此外，理化性质分析揭示了LAB上清液中的活性代谢产物，特别是在所有样品中均检测到的乳酸。此外，本研究还提出了关于乳腺炎细菌病原体体外感染CPAE牛内皮细胞的新发现，并证明了细菌感染牛内皮细胞后出现的细胞病变效应，如空泡化、巨细胞增多和细胞毒性。此外，LAB上清液中的代谢产物对CPAE牛内皮细胞上引起乳腺炎的细菌病原体的细菌定植和感染具有保护作用，并提高了细胞活力。本研究结果表明，LAB样品中的代谢产物有望成为牛乳腺炎的替代治疗剂。
