PR001394 (Project)

Description:Staphylococcus aureus is a medically important pathogen that exhibit high metabolic versatility allowing it to infect various niches within a host. S. aureus utilizes two major transcriptional regulators, CodY and CcpA, to remodel metabolic and virulence gene expression in response to changing environmental conditions. Previous studies revealed that inactivation of either codY or ccpA has a pronounced impact on different aspects of staphylococcal physiology and pathogenesis. To determine the contribution and interplay of these two regulators in modulating central metabolism, virulence, and biofilm development we constructed and characterized codY ccpA double mutant in S. aureus UAMS-1. In line with previous studies, we found that CcpA and CodY control cellular metabolic status by altering carbon flow through the central and overflow metabolic pathways. Our results demonstrate that ccpA inactivation impairs biofilm formation and decreases incorporation of eDNA into the biofilm matrix while disrupting codY resulted in a robust structured biofilm tethered together with eDNA and PIA. Interestingly, inactivation of both codY and ccpA decreases biofilm biomass and neglects eDNA release in the double mutant. Compared to inactivation of codY, the codY ccpA mutant did not overexpress toxins but maintained overexpression of amino acid metabolism pathways. Furthermore, codY ccpA mutant produced higher amounts of PIA, in contrast to the wild-type strain and ccpA mutant. Overall, results of this study suggest that interplay between CodY and CcpA modulates central metabolism to optimize growth on preferred carbon sources while repressing virulence gene expression until nutrient limitation requires scavenging nutrients from the host