Exposure to TiO(2) Nanoparticles Increases Listeria monocytogenes Infection of Intestinal Epithelial Cells

Titanium dioxide nanoparticles (TiO(2) NPs) are widely used in a variety of consumer products. Cellular exposure to TiO(2) NPs results in complex effects on cell physiology that could impact biological systems. We investigated the behavior of Listeria monocytogenes in intestinal epithelial cells pre-treated with either a low or high (1 and 20 µg/cm(2)) dose of TiO(2) NPs. Our results indicate that the pre-treated cells with a low dose became more permissive to listeria infection; indeed, both adhesion and invasion were significantly increased compared to control. Increased invasion seems to be correlated to cytoskeletal alterations induced by nanoparticles, and higher bacterial survival might be due to the high levels of listeriolysin O that protects L. monocytogenes from reactive oxygen species (ROS). The potential risk of increased susceptibility to L. monocytogenes infection related to long-term intake of nanosized TiO(2) at low doses should be considered.