Vibrio Cholerae Interaction with the Commensal Fungus Candida Albicans

Vibrio spp. are highly motile Gram-negative bacteria, ubiquitously found in aquatic environments. Some Vibrios are responsible for disease and morbidity of marine invertebrates and humans, while others are studied for their symbiotic interactions. Vibrio spp. are motile due to synthesis of flagella that rotate and propel the bacteria. Flagellum-mediated motility is an integral part of the bacterial life cycle inside the host and in the aquatic environment, and is intimately connected to biological and cellular processes such as chemotaxis, biofilm formation, colonization, and virulence of Vibrio spp. The V. cholerae flagellar filament is composed of five flagellin subunits (FlaA, FlaB, FlaC, FlaD, and FlaE); however, only FlaA is necessary and sufficient for filament synthesis. In the marine environment, V. cholerae colonizes chitinous surfaces, which activates pathogenesis and induces natural competence. Virulence of V. cholerae is multifaceted and is partially regulated by the flagellar transcription hierarchy. Chitin is also present in the cell wall of fungi, and chitinous commensal fungi of the human GI tract are likely to interact with V. cholerae during infection. Candida albicans is an opportunistic fungal pathogen that is commonly found as a commensal in the human GI tract. We have found that V. cholerae forms mixed biofilms and inhibits morphogenesis of C. albicans. Characterization of V. cholerae-C. albicans interactions may lead to the identification of therapeutics for candidiasis and will illuminate the influence of fungi within the GI tract on susceptibility to cholera.