Assessment of biosecurity traits and in situ antibacterial activities of Weissella cibaria strains isolated from Campos das Vertentes, Minas Gerais, Brazil focused for a potential probiotic and food application

Abstract

The antagonistic Weissella cibaria strains W21, W25 and W42 are characterized in this study for additional beneficial properties. These strains display therefore high scores of adhesion to intestinal cell-lines and capacities to exclude in situ pathogens such as methicillin resistant Staphylococcus aureus (MRSA S1) and Escherichia coli 184, which is resistant to colistin. Further, W. cibaria W21, W25 and W42 were hemolysis-negative, non-cytotoxic towards a mix of eukaryotic Caco2 and HT-29 cell-lines, do not induce inflammation on the promonocytic human cell line U937, but were unable to survive conditions mimicking the human gastrointestinal tract. Their biosafety aspect was addressed in silico and experimentally by studying their blood-hemolysis and susceptibility to antibiotics. To sum up, W. cibaria W21, W25 and W42 have no acquired related antimicrobial resistance genes and mobile genetic elements (MGE) in their genomes. Nevertheless, their intrinsic resistance to vancomycin was established in vitro and confirmed with in silico analyses. Their difficulties to face the gastrointestinal conditions could be overcome by using appropriate delivery systems. Taking all these data together, we claim that W. cibaria W21, W25 and W42 are coming as excellent strains candidates with wide a range of industrial applications and bio-functional properties .