In VitroAntimicrobial Activity and Effect on Biofilm Production of a White Grape Juice (Vitis vinifera) Extract
Background. The aim of the present study was to evaluate the antimicrobial effect of a white grape juice extract (WGJe) against a range of Gram-positive and Gram-negative bacteria, yeasts, and the fungusAspergillus niger. WGJe was also tested on the production of bacterial biofilmsin vitro.Results. WGJe inhibitedin vitromost Gram-positive bacteria tested,Staphylococcus aureusATCC 6538P being the most sensitive strain (MIC values of 3.9 μg/mL). The effect was bactericidal at the concentration of 500 μg/mL. Amongst the Gram-negative bacteria,Escherichia coliwas the only susceptible strain (MIC and MBC of 2000 μg/mL). No effect on the growth ofCandidasp. and the fungusAspergillus nigerwas detected (MIC values > 2000 μg/mL). WGJe inhibited the biofilms formation ofE. coliandPseudomonas aeruginosawith a dose-dependent effect.Conclusions. WGJe exerted both bacteriostatic and bactericidal activityin vitro. The presented results could be used to develop novel strategies for the treatment of skin infections and against potential respiratory pathogens.