TonB-Dependent Systems of UropathogenicEscherichia coli: Aerobactin and Heme Transport and TonB Are Required for Virulence in the Mouse

Abstract
The uropathogenicEscherichia colistrain CFT073 has multiple iron acquisition systems, including heme and siderophore transporters. AtonBmutant derivative of CFT073 failed to use heme as an iron source or to utilize the siderophores enterobactin and aerobactin, indicating that transport of these compounds in CFT073 is TonB dependent. The TonBderivative showed reduced virulence in a mouse model of urinary tract infection. Virulence was restored when thetonBgene was introduced on a plasmid. To determine the importance of the individual TonB-dependent iron transport systems during urinary tract infections, mutants defective in each of the CFT073 high-affinity iron transport systems were constructed and tested in the mouse model. Mouse virulence assays indicated that mutants defective in a single iron transport system were able to infect the kidney when inoculated as a pure culture but were unable to efficiently compete with the wild-type strain in mixed infections. These results indicate a role for TonB-dependent systems in the virulence of uropathogenicE. colistrains.

This publication has 38 references indexed in Scilit: