Spatial determinants of quorum signaling in a Pseudomonas aeruginosa infection model

Significance Quorum sensing is a communication system that allows bacteria to coordinate their activities, and these systems are critical for virulence in several bacteria, including Pseudomonas aeruginosa . There is a significant gap in knowledge about how quorum sensing proceeds during infection, particularly how spatial organization of the infecting microbial community impacts signaling. Using a model that recapitulates the biogeographical properties of P. aeruginosa infection of the cystic fibrosis lung, we discovered that communication primarily occurs within P. aeruginosa aggregates and that communication between aggregates is only observed for very large aggregates containing ≥5,000 cells. This study identifies a critical role for spatial distribution and bacterial phenotypic heterogeneity in bacterial signaling during infection, and provides a platform for future ecological and evolutionary studies.