Pyochelin biotransformation byStaphylococcus aureusshapes bacterial competition withPseudomonas aeruginosain polymicrobial infections

Abstract

SummaryPseudomonas aeruginosaandStaphylococcus aureusare among the most frequently isolated bacterial species from polymicrobial infections of cystic fibrosis patients and chronic wounds. We applied mass spectrometry guided interaction studies to determine how chemical interaction shapes the fitness and community structure during co-infection of these two pathogens. We demonstrate thatS. aureusis equipped with an elegant mechanism to inactivate pyochelin via the yet uncharacterized methyltransferase Spm (staphylococcalpyochelinmethyltransferase). Methylation of pyochelin abolishes the siderophore activity of pyochelin and significantly lowers pyochelin-mediated intracellular ROS production inS. aureus. In a murine wound co-infection model, aS. aureusmutant unable to methylate pyochelin shows significantly lower fitness as compared to its parental strain. Thus, Spm mediated pyochelin methylation is a novel mechanism to increaseS. aureussurvival duringin vivocompetition withP. aeruginosa.