Serratia marcescens is able to survive and proliferate in autophagic-like vacuoles inside non-phagocytic cells

FEDRIGO, G. V; CAMPOY, E.M.; DI VENANZIO, G.; COLOMBO, M.I.; GARCÍA VÉSCOVI, E.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2011 vol. 6 p. 24054 - 24062

1932-6203

Serratia marcescens is an opportunistic human pathogen that represents a growing problem for public health, particularly inhospitalized or immunocompromised patients. However, little is known about factors and mechanisms that contribute to S.marcescens pathogenesis within its host. In this work, we explore the invasion process of this opportunistic pathogen toepithelial cells. We demonstrate that once internalized, Serratia is able not only to persist but also to multiply inside a largemembrane-bound compartment. This structure displays autophagic-like features, acquiring LC3 and Rab7, markersdescribed to be recruited throughout the progression of antibacterial autophagy. The majority of the autophagic-likevacuoles in which Serratia resides and proliferates are non-acidic and have no degradative properties, indicating that thebacteria are capable to either delay or prevent fusion with lysosomal compartments, altering the expected progression ofautophagosome maturation. In addition, our results demonstrate that Serratia triggers a non-canonical autophagic processbefore internalization. These findings reveal that S. marcescens is able to manipulate the autophagic traffic, generating asuitable niche for survival and proliferation inside the host cell.