Comparative anti-microbial and anti-biofilm activities of postbiotics derived from kefir and normal raw milk lactic acid bacteria against bovine mastitis pathogens
Hyeon-Jin Kim, Hye‐Young Youn, Jin‐San Moon, Hyunsook Kim, Kun‐Ho Seo
Abstract
Bovine mastitis, caused by pathogens including Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli, poses a significant challenge to the dairy industry. This study aimed to investigate the underlying mechanisms of the anti-microbial and anti-biofilm activities of postbiotics derived from lactic acid bacteria against bovine mastitis pathogens. Kefir-derived Lentilactobacillus kefiri LK1 produced significantly more lactic acid than normal raw milk-derived Enterococcus faecium EFM2, which was attributed to differences in biochemical activities. At an optimum concentration of 25%, both L. kefiri LK1 (POS_LK1) and E. faecium EFM2 (POS_EFM2) postbiotics exhibited anti-microbial and anti-biofilm activities by modulating hydrophobicity, auto-aggregation, and exopolysaccharide (EPS) production phenotypes and genotypes of mastitis pathogens. POS_LK1 treatment reduced auto-aggregation and EPS production by E. faecalis and downregulated wspA and pelA expression in P. aeruginosa compared to those in POS_EFM2. Therefore, our results suggest that POS_LK1 could be used in the dairy industry as an anti-biofilm agent to effectively prevent pathogenic biofilm-induced bovine mastitis.