Orientia tsutsugamushi : A life between escapes

Intracellular bacteria have evolved different strategies to invade, replicate and persist in, and eventually exit from their hosts. The life cycle of the mite-borne, obligate intracellular pathogen Orientia tsutsugamushi (Ot), the causative agent of human scrub typhus, differs in many aspects from that of other members of the Rickettsiales order. Particularly, the non-lytic cellular exit of individual Ot bacteria at the plasma membrane closely resembles the budding of enveloped viruses, but has only been rudimentarily studied at the molecular level. This brief review is focused on the current state of knowledge of escape events in the life cycle of Ot. Also, open research questions and novel experimental approaches are proposed.