Response and Biochemical Alteration of <i>Vibrio parahaemolyticus</i> to Chlorine-Containing Disinfectants

Abstract

Three Vibrio parahaemolyticus isolates 17802(tdh﹣, trh﹢, tlh﹢), 33846(tdh﹢, trh﹣, tlh﹢) and 05432 (tdh﹣, trh﹣, tlh﹢) were exposed to chloramine-T and sodium hypochlorite to investigate their susceptibility and resistance to chlorine-containing disinfectants. Results showed that sublethal disinfectant condition contributed to the formation of resistant strains, which minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were 2 folds higher than original strains. Differences were observed in physiological and biochemical properties between the original and resistant strains including growth kinetics, cultural character and biochemical characterizations, the resistant strains demonstrated higher lag phase than the original strains in the growth of tryptic soy broth (TSB) with adding 2.5% NaCl. They lost the abilities to grow in thiosulfate citrate bile sucrose（TCBS）media and chromogenic (CHROM) agar and to produce certain proteases such as lysine decarboxylase, ornithine decarboxylase and urease. The most significant change in biochemical characters of the strains was that the resistant strains could grow in the media without containing salts while the original strains could not.