Survival strategies learned from an opportunistic pathogen

BRUNA, R.; LAZZARO, M.; GARCÍA VÉSCOVI, E.; MARISCOTTI, J.F.; MOLINO, MV

Santiago de Chile

Conferencia; XXIV Congreso Latinoamericano de Microbiología; 2018

ALAM

Serratia are ubiquitous bacteria that can beisolated from a wide variety of environmental niches, ranging from water andsoil to air. In particular, S. marcescens is an emergent health-threateningopportunistic pathogen. Outbreaks due to S.marcescens strains resistant to multiple antibacterial agents and highincidence in intensive and neonatal care units are increasingly being reported.The Word Health Organization has included Serratia in the ranking list of bacteria that should be prioritizedin the efforts to increase research and development of new antimicrobial agentsto counteract infections.In addition, S. marcescens has been recentlyidentified as one of the three most abundant microbial species that colonizesthe dysbiotic gut of Crohn patients, in detriment of beneficial bacteria. In spiteof this, few reports have in-depth characterized the mechanisms that Serratia employs to invade, survive and disseminate outside and within the host.Wewill discuss our recent findings, disclosing the role of the Rcssignal transduction systems as a master regulator of theexpression of key effectors required for the interaction of Serratia with the host as well as beingthe transcriptional regulatory mechanism that finely tunes the firing of the TypeVI Secretion System in the competition struggle against other bacteria. We willalso explore the roleof the PrtA metalloprotease in the capacity of the bacteria to form biofilms.Finally, we will show our recent advances in the understanding of the invasionprocess of S. marcescens to hostcells, revealing aspects of intracellular traffic and the strategy deployed by thepathogen to escape and spread outside the invaded cell.