Antagonistic interactions among marine bacteria impede the proliferation of Vibrio cholerae.

Changes in global climate have raised concerns about the emergence and resurgence of infectious diseases. Vibrio cholerae is a reemerging pathogen that proliferates and is transported on marine particles. Patterns of cholera outbreaks correlate with sea surface temperature increases, but the underlying mechanisms for rapid proliferation of V. cholerae during ocean warming events have yet to be fully elucidated. In this study, we tested the hypothesis that autochthonous marine bacteria impede the spread of V. cholerae in the marine environment. It was found that some marine bacteria are capable of inhibiting the growth of V. cholerae on surfaces and that bacterial isolates derived from pelagic particles show a greater frequency of V. cholerae inhibition than free-living bacteria. Vibrio cholerae was less susceptible to antagonism at higher temperatures, such as those measured during El Niño-Southern Oscilliation and monsoonal events. Using a model system employing green fluorescent protein-labeled bacteria, we found that marine bacteria can directly inhibit V. cholerae colonization of particles. The mechanism of inhibition in our model system was linked to the biosynthesis of andrimid, an antibacterial agent. Antibiotic production by the model antagonistic strain decreased at higher temperatures, thereby explaining the increased competitiveness of V. cholerae under warmer conditions. These findings suggest that bacterium-bacterium antagonism is a contributing mechanism in regulating the proliferation of V. cholerae on marine particles.