Genetic and environmental determinants of surface adaptations in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is a well-studied Gram-negative opportunistic bacterium that thrives in markedly varied environments. It is a nutritionally versatile microbe that can colonize a host as well as exist in the environment. Unicellular, planktonic cells of P. aeruginosa can come together to perform a coordinated swarming movement or turn into a sessile, surface-adhered population called biofilm. These collective behaviours produce strikingly different outcomes. While swarming motility rapidly disseminates the bacterial population, biofilm collectively protects the population from environmental stresses such as heat, drought, toxic chemicals, grazing by predators, and attack by host immune cells and antibiotics. The ubiquitous nature of P. aeruginosa is likely to be supported by the timely transition between planktonic, swarming and biofilm lifestyles. The social behaviours of this bacteria viz biofilm and swarm modes are controlled by signals from quorum-sensing networks, LasI-LasR, RhlI-RhlR and PQS-MvfR, and several other sensory kinases and response regulators. A combination of environmental and genetic cues regulates the transition of the P. aeruginosa population to specific states. The current review is aimed at discussing key factors that promote physiologically distinct transitioning of the P. aeruginosa population.

Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival

“…Additionally, the expression of all the virulence factors mentioned above is synchronously regulated by the P. aeruginosa QS systems in a population density-dependent manner [195,196]. Other phenotypic traits controlled by these QS systems include motility (swarming, swimming, and twitching), nutrient metabolism, stress response and antibiotic resistance [197][198][199]. A significant decline in P. aeruginosa virulence and cytotoxicity is noted in QS-deficient mutants [200].…”

Antimicrobial resistance of Pseudomonas aeruginosa: navigating clinical impacts, current resistance trends, and innovations in breaking therapies

“…These biofilms can develop in various environments, including the anaerobic conditions found in the lungs of cystic fibrosis (CF) patients (Valentin et al, 2022). Biofilm formation by P. aeruginosa is a finely tuned process regulated by various factors: Quorum Sensing Systems: P. aeruginosa employs multiple quorum sensing systems, including LasI-LasR, RhlI-RhlR, and PQS-MvfR, which contribute to the formation of mature and differentiated biofilms (Ambreetha and Singh, 2023). Two-Component Regulatory Systems: The GacS/GacA and RetS/LadS two-component systems play crucial roles in regulating biofilm formation.…”