Equine endometrial bacteria inhibition by metabolite and extracellular vesicles of Lactobacillus acidophilus and lactiplantibacillus plantarum.

Endometritis is one of the main reproductive disorders in mares and due to the increasing prevalence of antibiotic resistance, the use of probiotics in the prevention and treatment of endometritis in mares has gained interest, given their potential to restore and maintain a healthy uterine microbiota. Therefore, the aim of this study was to evaluate the antimicrobial properties of total metabolites of Lactobacillus acidophilus (LA) and Lactiplantibacillus plantarum (LP) against common equine endometrial pathogenic bacteria in vitro (Acinetobacter baumannii, Escherichia coli (1), Escherichia coli (2), Escherichia coli (3), Escherichia coli (4), Enterobacter cloacae, Streptococcus equi, Staphylococcus warneri, Actinobacillus equi and Klebesiella pneumoniae), as well as to assess their low molecular weight metabolites (loM) and extracellular vesicle (EVs) inhibition capacity over a multidrug-resistant E. coli isolated from mares with clinical endometritis. The total metabolites of LA showed better inhibition on A. baumannii, E. coli (1) and E. cloacae, while those of LP inhibited E. coli (4), S. equi and A. equi. Besides total metabolites, loM of LA and LP can inhibit E. coli. LA EVs were more effective in preventing E. coli (2) compared to LA loM, while LP EVs presented inhibition but below 90%. The use of LA and LP in the mare's uterus may be an interesting approach to controlling endometritis. In addition to metabolites, EVs can contribute to the inhibition of multidrug-resistant E. coli.