title: Role of catecholate siderophores in gram-negative bacterial colonization of the mouse gut.
abstract: We 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(1)-, 10(5)-, and 10(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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, Stevenson Life Sciences Research Center, Norman, OK, USA.
authors.forename: Hualiang
authors.initials: H
authors.lastname: Pi
authors.forename: Shari A
authors.initials: SA
authors.lastname: Jones
authors.forename: Lynn E
authors.initials: LE
authors.lastname: Mercer
authors.forename: Jessica P
authors.initials: JP
authors.lastname: Meador
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Caughron
authors.forename: Lorne
authors.initials: L
authors.lastname: Jordan
authors.forename: Salete M
authors.initials: SM
authors.lastname: Newton
authors.forename: Tyrrell
authors.initials: T
authors.lastname: Conway
authors.forename: Phillip E
authors.initials: PE
authors.lastname: Klebba
mesh_terms: D000818:Animals; D004758:Enterobactin / Q000096:biosynthesis; D004926:Escherichia coli / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D051379:Mice; D017262:Siderophores / Q000096:biosynthesis*
chemical_list: D005290:Ferric Compounds; D017262:Siderophores; D004758:Enterobactin