Molecular response of Vibrio parahaemolyticus to the sanitizer peracetic acid

Peracetic acid (PAA) is a common oxidative sanitizer that is used in the food industry against various microorganisms. Limited information on the response of bacteria to this biocide is available. This study investigates the molecular response of the prevalent seafood-borne pathogenic Vibrio parahaemolyticus to PAA using mutants of peroxide scavenging genes. Among katE1, katE2, katG1, katG2, ahpC1 and ahpC2, and their regulator oxyR gene mutants, oxyR and katE mutants were highly susceptible to PAA. The growth and lethality of V. parahaemolyticus were harmed by 15 ppm of PAA in the Delta katE1E2 double mutant, and were significantly ameliorated in the presence of the katE1 gene in the wild-type strain and the gene-complementary strains that were pre adapted in 2 ppm of PAA or 100 mu M hydrogen peroxide. The application of PAA to these strains induced the accumulation of reactive oxygen species. The reduction of the level of hydrogen peroxide and gene expression during this treatment was influenced by the presence of katE genes. This investigation confirmed the major role of katEl and a compensatory role of katE2 in the resistance of V. parahaemolyticus to PAA, and demonstrated some minor differences in the responses of this bacterium against PAA and hydrogen peroxide.