Inhibitory Activity of Vaginal Lactobacilli Against Human Pathogens

ABSTRACTLactic acid bacteria have long been considered as protective microflora, able to displace and kill different pathogens. Twenty vaginal strains, pre-selected as probiotics, were additionally characterized as effective antagonists against human pathogens. Four clinical reference strains- Staphylococcus aureus ATCC 25923, Staphylococcus aureus (MRSA) ATCC 39592, Pseudomonas aeruginosa ATCC 27853 and E. coli ATCC 25922 were used as test-cultures in initial screening procedure. The active strains belonging to the species L. fermentum, L. gasseri and L. salivarius were tested against 10 antibiotic-resistant and problematic clinical isolates. In vitro the growth inhibition of two Acinetobacter baumannii and two Pseudomonas aeruginosa out-patient strains was observed. The active antimicrobials were the lactic acid and hydrogen peroxid produced during the cultivation of ten vaginal strains, in combination with termo and proteinase- sensitive bacteriocin-like metabolites. Our results provide a promising bas...