IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Serratia marcescens invades and proliferates into epithelial cells modulating the autophagic pathway
Autor/es:
FEDRIGO, G. V; CAMPOY, E.M.; COLOMBO, M.I.; GARCÍA VÉSCOVI, E.
Lugar:
San Diego, California, EEUU
Reunión:
Congreso; 110th General Meeting of the American Society for Microbiology; 2010
Institución organizadora:
ASM
Resumen:
Abstract: Serratia marcescens is wide host range enterobacterium that can be isolated from plants, insects and nematodes, also being an opportunistic pathogen of mammals. In humans, S. marcescens is commonly isolated from urinary tract infections, pneumonia, surgical wounds, and bloodstream infections, mostly from intensive care unit patients. The incidence of S. marcescens infections has increased over the last years. This emergence is mainly attributed to the acquisition of multiple antibiotic resistance and to the capacity of the bacteria to adhere and persist on unanimated surfaces. However, only few reports have in depth analyzed the mechanisms used by Serratia to invade, survive and disseminate within the host. In this work, we explore the invasion process of S. marcescens to epithelial cells. We demonstrate that once inside the cell, Serratia is able to inhabit and proliferate inside a large membrane-bound compartment. This vesicle exhibits autophagic-like features, as it acquires LC3 and Rab7, markers that are typically recruited throughout the progression of the autophagosome biogenesis. However, we show that these vacuoles are non-acidic and have no degradative properties, indicating a blockage of the delivery to lysosomal compartments. We demonstrate that a proficient autophagic machinery is required for Serratia to survive and proliferate intracellularly. In addition, our results put forth that autophagy can be induced extracellularly by Serratia before internalization, by the sole expression of the secreted bacterial haemolysin. These findings shed light on the mechanism that Serratia employs to invade and multiply inside non-professional phagocytic cells and reveal that S. marcescens constitutes a suitable model organism to explore the strategies that opportunistic pathogens have evolved to succeed in the host organism.  Acknowledgments/ References: This work was funded by Agencia Nacional de Promoción Científica y Tecnológica and by CONICET, Argentina.