Selected Plant Protection Bacillus Strains Increase Food Safeness by Inhibiting Human Pathogenic Bacteria

Abstract

Food illnesses can occur due to the presence of human pathogen contaminants in fresh farm products. Herbs, vegetables and fruits, especially from organic agriculture, are highly exposed to animal and human pathogens. However, safe microbial antagonists, approved for plant protection, could be a solution to prevent this health risk to occur. The aim of this study is to reveal several beneficial bacterial strains reducing the prevalence of human and animal pathogens. Tested beneficial strains were previously described as promising biocontrol agents against soilborne pathogens of field crops and vegetables. Moreover, their endophyte adaptation, ensures an intimate relation with their plant hosts. Therefore, within this study we analyzed the inhibitory activity of seven biocontrol endophytes against 24 reference bacterial strains, of which 19 important human and animal pathogens. Some of the tested beneficial strains revealed antibacterial activity against a wide spectrum of pathogens, such as: Bacillus cereus, Enterococcus faecalis, Escherichia coli, Listeria ivanovii, L. monocytogenes, Rhodococcus equi, Salmonella enterica, S. typhimurium, Staphylococcus aureus, S. epidermidis and Streptococcus pyogenes. Due to their antagonistic activity, the beneficial strains were studied through molecular techniques to reveal their functional genes involved in antimicrobial compounds synthesis. Genes encoding for iturin A, surfactin, bacilysin, bacillomycin and bacillaene were found in these biocontrol strains. Therefore, we could consider such beneficial strains as promising candidates for plant protection and human safety.