Impact of acid on survival of Vibrio vulnificus and Vibrio vulnificus phage.

Three strains of Vibrio vulnificus and V. vulnificus phages were tested for acid sensitivity at 21 degrees C. V. vulnificus strain 304 was more resistant to pH 4.0 than strains CVD-1 and A-9, whereas acid sensitivities of V. vulnificus strains at pH 3.0 and 2.0 were similar. V. vulnificus phage strain 110A-7 was more resistant to pH 4.0 than strain 153A-7, whereas acid sensitivities of phage strains at pH 3.5 and 3.0 were similar. Numbers of V. vulnificus and its phage were close to the limit of detection after 100 s at pH 2.0 and after 24 min at pH 3.0. Acid D-values at 21 degrees C decreased as pH decreased for both V. vulnificus and phages. D-values of phage strains at pH 3.5 were 10-fold greater than those of host strain at pH 4.0. D-values of phage strains were slightly greater than those of host strain at pH 3.0. These results suggest that V. vulnificus and its phage were very sensitive to pH of less than 3.0, although V. vulnificus phages were more resistant to acid than their host.