In Vitro Anti- Mode of Action of and .

is an important vaginosis causative agent, affecting several women worldwide each year. This study reports on two strains of lactic acid bacteria ( CRL35 and ST88Ch) expressing bacteriocin-like inhibitor substances (BLIS) active against 1281. Both strains were γ-hemolytic and not affected by numerous antibiotics, contraceptives, and commercial drugs, suggesting safety for human use. The recorded antimicrobial activity of semi-purified BLIS was 25,600 AU/mL for CRL35 and 800 AU/mL for ST88Ch. Treatment of BLIS with 1 mg/mL proteinase K resulted in complete loss of antimicrobial activity against ATCC 15313 and partial loss of activity against 1281. The killing effect of the semi-purified BLIS on cell suspensions of 1281 after 9 h of contact was dose-dependent: for CRL35, 400 AU/mL to 25,600 AU/mL caused 63.61% to 79.35% lysis, while for ST88Ch, 200 AU/mL to 800 AU/mL caused 29.32% to 31.25% cell lysis. The effects of temperature, pH, and presence of the contraceptive Nordette-28 on the adsorption levels of the BLIS to 1281 were also evaluated. Nordette-28 (10% or 20%) promoted increased adsorption of both studied BLIS to the cells of 1281 at pH 5.0, while a minor effect was observed at pH 3.0. Different levels of aggregation between 1281 and CRL35 or ST88Ch were recorded, and optimal adsorption levels were recorded at 37 °C. Appropriate BLIS-producing strains can effectively contribute to the equilibrium of vaginal microbial and reduce negative consequences from the development of infections.