Project name: The response of Streptococcus pneumoniae to antibiotic stress on the transcriptome of a competence negative strain

Description: The aim of this study is to identify the rapid (RR) and adaptative (AR) response of S. pneumoniae to aztreonam and clavulanic acid stress on transcriptional levelStreptococcus pneumoniae is able to acquire antibiotic resistance by activation of competence and subsequent DNA uptake. Several antibiotics induce competence by disrupting protein-quality control or perturbing DNA replication. Here, we demonstrate that aztreonam (AZT) and clavulanic acid (CLA) also promote competence. We show that AZT and CLA induce cell chain formation by targeting the D,D-carboxypeptidase PBP3. In support of the hypothesis that chain forming promotes competence, we demonstrate that an autolysin mutant (𝞓lytB) is hypercompetent. As competence is initiated by the binding of a small extracellular peptide (CSP) to a membrane-anchored receptor (ComD), we wondered if chain formation alters CSP diffusion and thereby sensing by ComD. Indeed, the presence of AZT or CLA affects competence synchronization. Artificially reducing CSP diffusion by increasing culture medium viscosity also triggers competence. Together, our data show that AZT and CLA effectively switch CSP-based quorum sensing to autocrine-like signalling, as CSP is now retained to chained cells and no longer shared in a common pool.Overall design: The different conditions were compared to each other. With or withour the short (rapid response) or long (adaptative response) presence of the compounds. The slide configuration also contained 6 replicate spots for each gene.

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: Medical

Last updated: 2018-03-08