Adaptive Interactions of spp. with in Cystic Fibrosis Chronic Lung Co-Infection.

In the lungs of patients with cystic fibrosis (CF), the main pathogen is often co-isolated with other microbes, likely engaging in inter-species interactions. In the case of chronic co-infections, this cohabitation can last for a long time and evolve over time, potentially contributing to the clinical outcome. Interactions involving the emerging pathogens spp. have only rarely been studied, reporting inhibition of biofilm formation. To evaluate the possible evolution of such interplay, we assessed the ability of spp. isolates to affect the biofilm formation of co-isolated strains during long-term chronic co-infections. We observed both competition and cohabitation. An sp. isolate secreted exoproducts interfering with the adhesion ability of a co-isolated strain and affected its biofilm formation. Conversely, a clonal sp. strain later isolated from the same patient, as well as two longitudinal strains from another patient, did not show similar competitive behavior against its co-isolates. Genetic variants supporting the higher virulence of the competitive sp. isolate were found in its genome. Our results confirm that both inter-species competition and cohabitation are represented during chronic co-infections in CF airways, and evolution of these interplays can happen even at the late stages of chronic infection.