Evaluation of Enterococcus mundtii ST4SA and Lactobacillus plantarum 423 as probiotics by using a gastro-intestinal model with infant milk formulations as substrate.

Enterococcus mundtii ST4SA and Lactobacillus plantarum 423 produce bacteriocins with activity against a number of Gram-positive and Gram-negative bacteria. Both strains survived intestinal conditions simulated in a gastro-intestinal model (GIM) with infant milk formulations as substrate and prevented the growth of Listeria monocytogenes ScottA. The strains are inhibited by the antibiotics amoxicillin, cefadroxil, roxithromycin and doxycycline, anti-inflammatory medicaments containing meloxicam, ibuprofen and sodium diklofenak, and analgesics containing paracetamol, codeine phosphate and promethazine. Strain 423 is sensitive to vancomycin and does not contain genes encoding gelatinase, cell aggregation substance (AS), adhesion to collagen (Ace), enterococcus surface protein (Esp), Enterococcus faecalis endocarditis antigen (EfaAfs), cytolysin and non-cytolysin (beta-hemolysin III). Genes encoding AS, cytolysin and non-cytolysin (beta-hemolysin III) were amplified from the genome of strain ST4SA. Survival of strains ST4SA and 423 improved when used as combined cultures in the GIM and compared well with the survival of commercially available probiotics subjected to the same conditions.