Nisin Z and lacticin 3147 improve efficacy of antibiotics against clinically significant bacteria.

To determine if bacteriocins improve antibiotic efficacy. Deferred antagonism assays identified bacteriocins with activity. Growth curves and time kill assays demonstrated bactericidal activity of antimicrobial combinations, and checkerboard assays confirmed synergy. Methicillin-resistant -infected porcine skin model determined efficacy. Subinhibitory concentrations of lacticin with penicillin or vancomycin resulted in complete growth inhibition of strains and the improved inhibitory effect was apparent after 1 h. Nisin with methicillin proved more effective against methicillin-resistant than either antimicrobial alone, revealing partial synergy and significantly reduced pathogen numbers on porcine skin after 3 h compared with minimal inhibition for either antimicrobial alone. Nisin Z and lacticin 3147 may support the use of certain antibiotics and revive ineffective antibiotics.