UC Riverside

Quorum sensing (QS) is a bacterial communication process that allows bacteria to alter gene expression based on environmental signals. Autoinducer-2 (AI-2) is one of these signaling molecules that regulates the virulence of the gastrointestinal pathogen Vibrio cholerae, which causes the diarrheal disease cholera that affects millions of people worldwide. Research on healthy and malnourished humans has shown that the structure of gut microbiome is different and differentially able to resist V. cholerae colonization, pathogen infection, and host immune response and treatment. However, the effect of AI-2 produced by different bacteria in susceptible and resistant microbiomes on their community and on V. cholerae is not well understood. To this end I constructed Escherichia coli expressing luxS gene from different microbes and combined them with different model communities of human gut microbes resembling health individuals or individuals recovering from diarrhea and tested in mouse models. We show microbiota-associated biofilm regulation in V. cholerae providing resistance against host intestinal environmental stress and AI-2 signal mediated microbiome structural and gene expression change. Our findings suggest that the composition of the gut microbiome is affected by AI-2 signal, and at the time of infection or treatment, the composition is crucial to host resistance against infection. This potentially provides a direction for the prevention and/or improved resistance to pathogen infection as well as immunotherapy.