Serratia marcescens INVADE EPITHELIAL CELLS AND FINDS A SUITABLE NICHE TO SURVIVE AND REPLICATE

FEDRIGO, GRISELDA; CAMPOY, EMANUEL MARTIN; VESCOVI, ELEONORA; COLOMBO MARIA ISABEL

Tucuman

Congreso; Reunion SAIB XLV; 2009

Serratia marcescens is an opportunistic human pathogen associated with urinary andrespiratory tract infections, endocarditis, osteomyelitis, meningitis and septicaemia. Thismicroorganism produces numerous extracellular proteins that are predicted to play a roll inbacterial environmental adaptative capacity and pathogenic potential. Previous reportshave shown that haemolysin ShlA and protease PrtA are able to acts as virulence factors;however, the mechanisms that Serratia employs to invade and disseminate in eukaryoticcells are presently unknown. In this work, we demonstrated that a clinical Serratiamarcescens isolated is able to invade and multiply in the CHO epithelial cells. Confocalmicroscopy analysis revealed that, since stages after entry, intracellular bacteria colocalizewith markers of early and late endosomes and this is maintaining until six hours postinfection.In addition, S. marcescens also colocalizes with the autophagosomal markerLC3 and is unable to replicate in mouse embryonic fibroblasts knock-out in atg5. InhibitingSerratia de novo synthesis with chloramphenicol blocked this process. Based on thesefindings, we propose that S. marcescens is able to transit through the endocityc pathwaywhile it actively induces an authophagy-like process that might favour the intracellularsurvival and proliferation of bacteria inside the host.