PRESENCE OF LYSOGENIC PHAGE IN THE OUTBREAK STRAINS OF VIBRIO-CHOLERAE O139

Four outbreak strains of Vibrio cholerae O139 from endemic areas of In dia and Bangladesh were found to carry lysogenic phage(s). All of thes e phage(s) produced turbid plaques characteristic of lysogeny on V. ch olerae MAK 757 (EI Tor, Ogawa) cells as well as on their VcA-1 lysogen s but were unable to infect V. cholerae 154 (classical) cells, the uni versal host for all classical phages. Colonies in the turbid plaques w ere O139 lysogens and these developed an auxotrophic requirement, main ly for purines suggesting the integration of the prophage into the hos t chromosome. The immunity profile of the O139 phage(s) was similar to that of phage a but differed in the sensitivity of the phage lysogen of V. cholerae MAK 757 to subsequent infection by phage beta.