The ability ofPseudomonas aeruginosato adopt a Small Colony Variant (SCV) phenotype is conserved, and not restricted to clinical isolates

Abstract

A subpopulation of Small Colony Variants (SCVs) is a frequently observed feature of Pseudomonas aeruginosa isolated from cystic fibrosis (CF) lungs biofilms. SCVs have almost exclusively been reported from infected hosts, essentially CF individuals or, by extension, from laboratory cultivation of strains originated from infected hosts. We previously reported the identification of P. aeruginosa SCVs emerging from a non-clinical strain and displaying features shared with clinical SCVs. In the present work, we investigated the ability of 22 P. aeruginosa isolates from various environmental origins to, under laboratory culture conditions, spontaneously adopt a SCV-like smaller alternative morphotype distinguishable from the ancestral parent strain. Unexpectedly, we found that all the P. aeruginosa strains tested have the ability to adopt a SCV morphotype, regardless of their origin. Based on the phenotypes already described for SCVs, the SCV-like morphotypes obtained were clustered in two groups displaying various phenotypic profiles, including one characteristic of already described SCVs. We conclude that the ability to switch to a SCV phenotype is a conserved feature in P. aeruginosa.

Pseudomonas aeruginosa isolates defective in function of the LasR quorum sensing regulator are frequent in diverse environmental niches

“…For instance, P. aeruginosa also forms small colony variants under specific conditions using phase variation as an adaptation mechanism. This ability was long associated with clinical isolates, but it was found to be conserved among environmental strains as well (Besse et al ., 2021).…”