Glucose Metabolism by Escherichia coli Inhibits Vibrio cholerae Intestinal Colonization of Zebrafish

Abstract

The <i><i>Vibrio cholerae</i></i> O1 serogroup is responsible for pandemic cholera and is divided into the classical and El Tor biotypes. Classical <i>V. cholerae</i> produces acid when using glucose as a carbon source, whereas El Tor <i>V. cholerae</i> produces the neutral product acetoin when using glucose as a carbon source. An earlier study demonstrated that <i>Escherichia coli</i> strains that metabolize glucose to acidic by-products drastically reduced the survival of <i>V. cholerae</i> strains <i>in vitro</i> In the present study, zebrafish were fed 1% glucose and either inoculated with single <i>V. cholerae</i> or <i>E. coli</i> strains or coinfected with both <i>V. cholerae</i> and <i>E. coli</i> A significant decrease in classical biotype colonization was observed after glucose feeding due to acid production in the zebrafish intestine. El Tor colonization was unaffected by glucose alone. However, the El Tor strain exhibited significantly lower colonization of the zebrafish when either of the acid-producing <i>E. coli</i> strains was coinoculated in the presence of glucose. An <i>E. coli</i> sugar transport mutant had no effect on <i>V. cholerae</i> colonization even in presence of glucose. Glucose and <i>E. coli</i> produced a prophylactic effect on El Tor colonization in zebrafish when <i>E. coli</i> was inoculated before <i>V. cholerae</i> infection. Thus, the probiotic feeding of <i>E. coli</i> inhibits <i>V. cholerae</i> colonization in a natural host. This suggests that a similar inhibitory effect could be seen in cholera patients, especially if a glucose-based oral rehydration solution (ORS) is administered in combination with probiotic <i>E. coli</i> during cholera treatment.