Growth and Antibiotic Susceptibility Studies on Vibrio parahaemolyticus

Abstract

In this paper, the growth of V. parahaemolyticus in different media, pH, salt concentrations, temperatures, chitin levels and the sensitivity of this organism to different concentrations of various antibiotics are presented. The strains grew luxuriantly on fish-based media especially on TSBFE NaCl medium. While all the strains grew between pH 5 and 9, none of them grew at pH 4 and 10. K-strains grew better than k+strains at various pH levels studied. Maximum growth for all strains occurred in 3% NaCl but none of the strains grew at 0% NaCl. The strains did not grow at 10°C and 46°C; the optimum growth temperature was found to be 37°C. Chitin (0.5-1%) enhanced the growth of stains. Though the sensitivity of the strains to various antibiotics did not vary significantly with the same medium, the results depended on the media employed. There was no appreciable difference in sensitivity to antibiotics between K+ and k- strains. The order of effectiveness of various antibiotics tested was: chloramphenicol>erythromicyn>sulfisoxazole>oleandomycin>leucomycin>kanamycin>tetracycline>colistin>novobiocin>penecillin. Among the five media employed for antibiotic sensitivity study, TCBS, BTB and TSAFE NaCl media showed uniform results compared to the other two media.