| Autor: |
Kostiuk B; Department of Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada., Becker ME; Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA., Churaman CN; Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA., Black JJ; Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA., Payne SM; Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA.; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA., Pukatzki S; Department of Biology, The City College of New York, New York, New York, USA., Koestler BJ; Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA. |
| Abstrakt: |
Vibrio cholerae is a Gram-negative pathogen, living in constant competition with other bacteria in marine environments and during human infection. One competitive advantage of V. cholerae is the ability to metabolize diverse carbon sources, such as chitin and citrate. We observed that when some V. cholerae strains were grown on a medium with citrate, the medium's chemical composition turned into a hostile alkaline environment for Gram-negative bacteria, such as Escherichia coli and Shigella flexneri. We found that although the ability to exclude competing bacteria was not contingent on exogenous citrate, V. cholerae C6706 citrate metabolism mutants Δ oadA -1, Δ citE , and Δ citF were not able to inhibit S. flexneri or E. coli growth. Lastly, we demonstrated that while the V. cholerae C6706-mediated increased medium pH was necessary for the enteric exclusion phenotype, secondary metabolites, such as bicarbonate (protonated to carbonate in the raised pH) from the metabolism of citrate, enhanced the ability to inhibit the growth of E. coli. These data provide a novel example of how V. cholerae outcompetes other Gram-negative bacteria. IMPORTANCE Vibrio cholerae must compete with other bacteria in order to cause disease. Here, we show that V. cholerae creates an alkaline environment, which is able to inhibit the growth of other enteric bacteria. We demonstrate that V. cholerae environmental alkalization is linked to the capacity of the bacteria to metabolize citrate. This behavior could potentially contribute to V. cholerae's ability to colonize the human intestine. |
