Trophic cooperation promotes bacterial survival ofStaphylococcus aureusandPseudomonas aeruginosa

In the context of infection,Pseudomonas aeruginosaandStaphylococcus aureusare frequently co-isolated, particularly in cystic fibrosis (CF) patients. Within lungs, the two pathogens exhibit a range of competitive and coexisting interactions. In the present study, we explored the impact ofS. aureuson the physiology ofP. aeruginosain the context of coexistence. Transcriptomic analyses showed thatS. aureussignificantly and specifically affects the expression of numerous genes involved inP. aeruginosacarbon and amino acid metabolism. In particular, 65% of the strains presented considerable overexpression of the genes involved in the acetoin catabolic (aco) pathway. We demonstrated that acetoin is (i) produced by clinicalS. aureusstrains, (ii) detected in sputa from CF patients and (iii) involved inP. aeruginosa'sacosystem induction. Furthermore, acetoin is catabolized byP. aeruginosa, a metabolic process that improves the survival of both pathogens by providing a new carbon source forP. aeruginosaand avoiding the toxic accumulation of acetoin onS. aureus. Due to its beneficial effects on both bacteria, acetoin catabolism could testify to the establishment of trophic cooperation betweenS. aureusandP. aeruginosain the CF lung environment, thus promoting their persistence.