Bacterial replication in the host cell cytosol.

Intracellular bacteria in mammalian host cells can either live in a membrane-bound vacuole modified to support bacterial growth, or escape from the primary phagosome into the host cell cytoplasm. Phagosomal escape is best studied in Listeria monocytogenes in which a pore-forming cytolysin and two phospholipases are involved in the lysis of the phagosomal membrane. The mechanisms of and requirements for cytoplasmic growth are less clear but there is growing evidence that proficient replication of bacteria in the cytoplasmic compartment requires specific bacterial and cellular preconditions.