Inhibition of Vibrio parahaemolyticus by a bacteriocin-like inhibitory substance (BLIS) produced by Vibrio mediterranei 1

Abstract

The aim of this research was to identify and partially purify new bacteriocin-like substances from strains of halophilic 'non-cholera' vibrios isolated from food sources. Forty-five halophilic Vibrio spp. strains were screened for antimicrobial production. Vibrio mediterranei 1, a nonpathogenic strain, showed antimicrobial activity towards Vibrio parahaemolyticus spp. and related species. The bacteriocin-like inhibitory substance (BLIS), released by the bacteria into growth media, was concentrated by ultrafiltration and characterized. BLIS was sensitive to proteinase K, was stable in the pH range 5-9, was resistant to organic solvents and was heat stable up to 75 degrees C. Initial purification of BLIS by size exclusion chromatography showed an apparent molecular mass of 63-65 kDa. This study reports the ability of V. mediterranei 1 to produce a bacteriocin-like substance inhibiting growth of V. parahaemolyticus spp. and other closely related bacteria. The strong activity of BLIS towards the human and fish pathogen V. parahaemolyticus and the persistence of antimicrobial properties under a variety of different conditions suggest its potential application in food microbiology.