Cell biology. Bacterial spelunkers

Bacteria that are engulfed by phagocytic cells of the immune system are usually destroyed once inside the host cell but not always. Why is it that sometimes engulfed bacteria survive and thrive quite happily inside the host cell? As Mulvey and Hultgren explain in their Perspective, the answer may lie in small indentations in the host cell plasma membrane called caveolae that direct certain signal transduction pathways inside the host cell (Shin et al.). If bacteria adhere to regions of the host cell surface that is rich in caveolae, they are better able to survive once inside the cell.