While the most ubiquitous extracellular signals faced by microbes are often from other microbes, how interspecies signals are sensed, the nature of these signals, and how signaling contributes to community behaviors necessary for human infection is unknown. We aim to determine the molecular mechanism underpinning how Pseudomonas aeruginosa chemotaxes towards other bacterial species.

This project seeks to understand how social bacteria detect secreted signals from competitors, through a “competition sensing” pathway that provides a selective advantage in polymicrobial communities.

Cyclic diguanylate (cdG) is a critical second messenger signaling molecule regulating diverse cellular behaviors in bacteria. We are working to understand how cdG regulates P. aeruginosa interspecies chemotaxis and competition sensing using a combination of bacteriology and structural biology approaches.

Polymicrobial interactions influence microbial survival and behavior during chronic infection, such as those in the airways of cystic fibrosis (CF) patients. Our studies in people with CF reveal an association with coinfection with the bacteria P. aeruginosa and Staphylococcus aureus and a decline in lung function. We seek to understand why coinfected patients have poor outcomes by studying bacteria infections directly from infected human samples.