AUTHOR=Loss Guilherme , Simões Patricia Martins , Valour Florent , Cortês Marina Farrel , Gonzaga Luiz , Bergot Marine , Trouillet-Assant Sophie , Josse Jêrome , Diot Alan , Ricci Emiliano , Vasconcelos Ana Tereza , Laurent Frédéric TITLE=Staphylococcus aureus Small Colony Variants (SCVs): News From a Chronic Prosthetic Joint Infection JOURNAL=Frontiers in Cellular and Infection Microbiology VOLUME=9 YEAR=2019 URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00363 DOI=10.3389/fcimb.2019.00363 ISSN=2235-2988 ABSTRACT=

Small colony variants (SCV) of Staphylococcus aureus have been reported as implicated in chronic infections. Here, we investigated the genomic and transcriptomic changes involved in the evolution from a wild-type to a SCV from in a patient with prosthetic joint infection relapse. The SCV presented a stable phenotype with no classical auxotrophy and the emergence of rifampicin resistance. Whole Genome Sequencing (WGS) analysis showed only the loss of a 42.5 kb phage and 3 deletions, among which one targeting the rpoB gene, known to be the target of rifampicin and to be associated to SCV formation in the context of a constitutively active stringent response. Transcriptomic analysis highlighted a specific signature in the SCV strain including a complex, multi-level strategy of survival and adaptation to chronicity within the host including a protection from the inflammatory response, an evasion of the immune response, a constitutively activated stringent response and a scavenging of iron sources.