Pi, HualiangJones, Shari A.Mercer, Lynn E.Meador, Jessica P.Caughron, Joyce E.Jordan, LorneNewton, Salete M.Conway, TyrrellKlebba, Phillip E.2013-03-042013-03-042012-11-29http://hdl.handle.net/2097/15334We investigated the importance of the production of catecholate siderophores, and the utilization of their iron (III) complexes, to colonization of the mouse intestinal tract by Escherichia coli. First, a ΔtonB strain was completely unable to colonize mice. Next, we compared wild type E. coli MG1655 to its derivatives carrying site-directed mutations of genes for enterobactin synthesis (ΔentA::Cm; strain CAT0), ferric catecholate transport (Δfiu, ΔfepA, Δcir, ΔfecA::Cm; CAT4), or both (Δfiu, ΔfepA, ΔfecA, Δcir, ΔentA::Cm; CAT40) during colonization of the mouse gut. Competitions between wild type and mutant strains over a 2-week period in vivo showed impairment of all the genetically engineered bacteria relative to MG1655. CAT0, CAT4 and CAT40 colonized mice 10[superscript 1]-, 10[superscript 5]-, and 10[superscript 2]-fold less efficiently, respectively, than MG1655. Unexpectedly, the additional inability of CAT40 to synthesize enterobactin resulted in a 1000-fold better colonization efficiency relative to CAT4. Analyses of gut mucus showed that CAT4 hyperexcreted enterobactin in vivo, effectively rendering the catecholate transport-deficient strain iron-starved. The results demonstrate that, contrary to prior reports, iron acquisition via catecholate siderophores plays a fundamental role in bacterial colonization of the murine intestinal tract.en-USAttribution 4.0 International (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/Catecholate siderophoresMouse intestinal tractEscherichia coliBacterial colonizationArticle (publisher version)