Transcriptome and secretome analyses of the adaptive response of Pseudomonas aeruginosa to suboptimal growth temperature

Resum

Pseudomonas aeruginosa is an opportunistic pathogen involved in various diseases including cystic fibrosis and nosocomial infections. Although this bacterium has been intensively studied at 37°C, little is known about its capacity to adapt and survive at suboptimal temperatures such as those encountered in hospitals. In this work, using transcriptomic and proteomic analyses, we aimed at identifying factors that could help P. aeruginosa to establish at local temperature (close to 25°C) and favor host infections. The virulence of this pathogen being multifactorial and depending on the extracellular release of toxins and degradative enzymes which are targeted to the host by several secretory systems, our study was focused on genes activated at 25°C, namely those encoding either components of secretory machineries or secreted proteins. These observations were enhanced by 2D-PAGE analyses showing that production of effectors from type I and type II secretion systems (respectively proteases AprA and PrpL) and of a hemolysin co-regulated protein (Hcp) related to the Type VI secretion system is specifically stimulated when growth temperature is lowered from 37°C to 25°C. Our study provides now a fundamental basis on which to build further analyses of unknown processes leading to the adaptation of P. aeruginosa to suboptimal growth temperature and which could favor nosocomial infection.