Nonhemorrhagic infarcton of the thalamus

Abstract

<h3>Abstract</h3> <i>Vibrio cholerae</i> respires both aerobically and anaerobically and, while oxygen may be available to it during infection, other terminal electron acceptors are proposed for population expansion during infection. Unlike gastrointestinal pathogens that stimulate significant inflammation leading to elevated levels of oxygen or alternative terminal electron acceptors, <i>V. cholerae</i> infections are not understood to induce a notable inflammatory response. To ascertain the respiration requirements of <i>V. cholerae</i> during infection, we used Multiplex Genome Editing by Natural Transformation (MuGENT) to create <i>V. cholerae</i> strains lacking aerobic or anaerobic respiration. <i>V. cholerae</i> strains lacking aerobic respiration were attenuated in infant mice 10⁵-fold relative to wild type, while strains lacking anaerobic respiration had no colonization defect, contrary to earlier work suggesting a role for anaerobic respiration during infection. Using several approaches, including one we developed for this work termed Comparative Multiplex PCR Amplicon Sequencing (CoMPAS), we determined that the <i>bd</i>-I and <i>cbb</i>₃ oxidases are essential for small intestinal colonization of <i>V. cholerae</i> in the infant mouse. The <i>bd</i>-I oxidase was also determined as the primary oxidase during growth outside the host, making <i>V. cholerae</i> the only example of a Gram-negative bacterial pathogen in which a <i>bd</i>-type oxidase is the primary oxidase for energy acquisition inside and outside of a host. <h3>Author Summary</h3> The bacterium that causes cholera, <i>Vibrio cholerae</i>, can grow with or without oxygen. When growing without oxygen it may use other molecules that serve the same purpose as oxygen, acting as a terminal electron acceptor in an energy-generating process known as respiration. Given the largely anaerobic nature of the gastrointestinal tract, and the lack of significant inflammation during cholera infection, a process that can stimulate elevated levels of oxygen and other terminal electron acceptors, we sought to understand the respiratory mechanisms of <i>V. cholerae</i> during infection. We used a powerful genome-editing method to construct mutant strains of <i>V. cholerae</i> lacking some or all of the complement of proteins required for aerobic or anaerobic respiration. By analyzing these mutants in the laboratory and in intestinal colonization of infant mice, we determined that the ability to respire without oxygen is completely dispensable for <i>V. cholerae</i> to thrive during infection. We determined that two of the four oxygen-dependent respiration mechanisms are essential for <i>V. cholerae</i> to grow during infection, with the other two dispensable for wild type levels of colonization.