Iron Metabolism and Adaptative Traits Associated with Virulence in Enterobacter cloacae Complex

Abstract

Iron is an essential micronutrient that shapes host-pathogen interactions during infection. However, the contribution of iron to the virulence adaptation of the Enterobacter cloacae complex (ECC) remain poorly characterized. This study profiled the effects of iron on E. roggenkampii and E. asburiae clinical isolates. Growth kinetics were assessed in Luria-Bertani broth supplemented with varying iron concentrations and 5% sheep blood, and EDTA. Recovered strains were used for motility and antibiotic susceptibility assays. Phenotypic virulence trait of iron-naive and iron-recovered strains was determined using biofilm formation assays. Whole-genome sequencing was conducted to identify genetic determinants associated with iron acquisition and metabolism. Presence of iron increased bacterial growth, reduced antibiotic susceptibility, and enhanced biofilm formation. At higher iron concentrations, iron-recovered strains exhibited increased biofilm biomass, while there was a high biofilm formation with iron-naive strains at lower iron levels. Genomic analysis identified genes associated with ferrous and ferric iron transport, heme uptake, siderophore biosynthesis, and virulence-related functions, including adhesion and biofilm formation. These findings demonstrate that iron availability and prior exposure modulate ECC physiology and phenotypic traits associated with virulence, supporting a role for iron in shaping adaptive pathogenic potential. Graphical AbstractThe influence of iron metabolism on virulence adaptation of Enterobacter cloacae complex O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/737523v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@be7149org.highwire.dtl.DTLVardef@ff7c4forg.highwire.dtl.DTLVardef@13a67acorg.highwire.dtl.DTLVardef@16c6987_HPS_FORMAT_FIGEXP M_FIG C_FIG