THE EFFECT OF INCUBATION-TEMPERATURE AND SODIUM-CHLORIDE CONCENTRATION ON THE GROWTH-KINETICS OF VIBRIO-ANGUILLARUM AND VIBRIO ANGUILLARUM-RELATED ORGANISMS

The effect of temperature and NaCl concentration on the growth kinetics of Vibrio anguillarum and V. anguillarum-related (VAR) strains was studied. For one wild VAR strain, NaCl concentration interfered with growth temperature parameters, in particular, with the maximum growth temperature but also with the optimum temperature (defined as the temperature at which mu(max) equals its maximal value mu(opt)), and with mu(opt) itself. For the same strain, optimal growth required the adding of NaCl to the medium to a final concentration of 1.5%, These results were not confirmed by tests on a V. anguillarum collection strain. When the NaCl concentration in the culture media was 1.5%, the optimum temperature for the nine strains studied ranged from 29.7 degrees C to 34 degrees C whereas the maximum temperature ranged between 35.3 degrees C and 38.5 degrees C. Hence, antibiotic susceptibility testing as well as biochemical identification might be carried out at 30 degrees C in the presence of 1.5% NaCl, which corresponded to a suboptimal growth.