Mastitis is one of the most important causes of loss of cattle production, burdening producers due to the increased cost of milk production and decreased herd productivity. The development of alternative methods for the treatment and prevention of mastitis other than traditional chemical antibiotic therapy needs to be implemented to meet international pressures to reduce the use of these drugs and promote the elimination of multiresistant microbial strains from the environment. Treatment with probiotic bacteria or yeast strains offers a possible strategy for the control of mastitis. The objective of this work was to isolate, identify, and characterize lactic bacteria from milk and the intramammary duct of Gyr, Guzerat, Girolando 1/2, and Holstein cattle breeds from Brazil. Samples of 115 cows were taken, a total of 192 bacteria isolates belonging to 30 species were obtained, and 81 were selected to evaluate their probiotic potential in in vitro characterization tests. In general, bacteria isolated from the mammary gland have low autoaggregation, cell surface hydrophobicity, and co-aggregation with mastitis etiological bacteria Staphylococcus aureus and Escherichia coli. Also, they have biofilm assembly capacity, inability to produce exopolysaccharides, high production of H₂O₂, and strong antagonism against mastitis pathogens. Ten lactic bacteria isolates were used in co-culture with human MDA-MB-231 breast epithelial cells to assess their adhesion capacity and impairment of the S. aureus invasion. Our results, therefore, contribute to the future production of new prevention and treatment tools for bovine mastitis.

乳腺炎是牛产量损失的最重要原因之一，由于牛奶生产成本增加和畜群生产力下降，给生产者带来负担。需要实施除传统化学抗生素疗法之外的治疗和预防乳腺炎的替代方法的开发，以满足减少这些药物使用和促进从环境中消除多重耐药微生物菌株的国际压力。用益生菌或酵母菌株治疗为控制乳腺炎提供了一种可能的策略。这项工作的目的是从来自巴西的 Gyr、Guzerat、Girolando 1/2 和荷斯坦牛品种的牛奶和乳腺内导管中分离、鉴定和表征乳酸菌。采集了 115 头奶牛的样本，总共获得了属于 30 个物种的 192 个细菌分离物，并选择了 81 个细菌来评估它们在体外表征测试中的益生菌潜力。一般来说，从乳腺中分离出来的细菌具有低自聚集性、细胞表面疏水性和与乳腺炎病原菌的共聚集性。金黄色葡萄球菌和大肠杆菌。此外，它们还具有生物膜组装能力，不能产生胞外多糖，H ₂ O ₂产量高，对乳腺炎病原体有很强的拮抗作用。十种乳酸菌分离物与人 MDA-MB-231 乳腺上皮细胞共培养，以评估它们的粘附能力和对金黄色葡萄球菌入侵的损害。因此，我们的研究结果有助于未来生产新的牛乳腺炎预防和治疗工具。