Characterization of iron acquisition pathways in Morganella morganii, an emerging opportunistic pathogen

Morganella morganii is an emerging multidrug-resistant pathogen, however vanishingly little is known about the basic biology of this bacterium. Iron is an essential micronutrient for almost all organisms and can markedly impact the fitness of bacteria when homeostatic concentrations are perturbed. As such, bacteria have finely tuned transcriptional responses to iron availability that mediate its uptake when limited, and its efflux and/or sequestration when in excess. Although M. morganii possesses genes for the uptake of small iron-binding molecules, known as siderophores, sequencing performed by our lab on modern clinical isolates reveals no discernable loci for siderophore synthesis. This project thus aims to identify the key iron uptake pathways and preferred source(s) of metal for M. morganii. Growth curves demonstrated utilization of diverse iron sources while RNA sequencing of M. morganii exposed to iron-deplete and -replete conditions revealed genes highly upregulated under nutrient limitation. These genes, implicated in the uptake of ferric citrate, siderophores, and ferrous iron, may contribute to the iron acquisition machinery of the pathogen and represent putative drug targets. For future directions, we aim to study these genes in detail by generating mutants in key candidates and assessing their individual effects on the iron-dependent growth of M. morganii.