An iron-regulated LysR-type element mediates antimicrobial peptide resistance and virulence in Yersinia pseudotuberculosis

Abstract

During the course of its infection of the mammalian digestive tract, the entero-invasive, Gram-negative bacteriumYersinia pseudotuberculosismust overcome various hostile living conditions (notably, iron starvation and the presence of antimicrobial compounds producedin situ). We have previously reported thatin vitrobacterial growth during iron deprivation raises resistance to the antimicrobial peptide polymyxin B; here, we show that this phenotype is mediated by a chromosomal gene (YPTB0333) encoding a transcriptional regulator from the LysR family. We determined that the product ofYPTB0333is a pleiotropic regulator which controls (in addition to its own expression) genes encoding the Yfe iron-uptake system and polymyxin B resistance. Lastly, by using a mouse model of oral infection, we demonstrated that YPTB0333 is required for colonization of Peyer's patches and mesenteric lymph nodes byY. pseudotuberculosis.