THE SECOND MESSENGER C-DI-GMP IS REQUIRED FOR Pseudomonas aeruginosa COMPETITION AGAINST Staphylococcus aureus

Los Cocos

Congreso; XVII Congreso Argentino de Microbiología General; 2022

SAMIGE

The airways of cystic fibrosis (CF) patients are colonized by multiple microorganisms whose prevalence varies with age. The two most commonly found bacteria in the mucus of CF patients are Pseudomonas aeruginosa and Staphylococcus aureus. The interaction between them has been widely studied and it is commonly admitted that P. aeruginosa outcompetes S. aureus. In this case, P. aeruginosa produces many molecules to inhibit the growth or even lysate S. aureus to compete for space and nutrients. The in vitro co-culture of both bacteria stimulates P. aeruginosa virulence factor production such as 4-hydroxy-2-heptylquinoline N-oxide (HQNO), phenazines, and the protease LasA. The second messenger bis-(3´→5´)-cyclic dimeric guanosine monophosphate (c-di-GMP) governs a wide range of cellular responses including biofilm formation, siderophore production, and virulence. C-di-GMP levels are modulated by diguanylate cyclases (DGCs, with the canonical GGDEF motif) andphosphodiesterases (PDEs, with either EAL or HD-GYP domains). P. aeruginosa genome possesses more than 40 genes predicted to encode for DGCs and PDEs. Here, we explored whether the specific action of these DGCs was a prerequisite for competition against S. aureus. For that, we use a P. aeruginosa UCBPP-PA14 DGC-free strain, previously engineered by a CRISPR/Cas9-based multiplex