Listeria monocytogenes is a Gram-positive bacterium that causes gastroenteritis, meningitis, encephalitis, and mother-to-fetus infections. This versatile pathogen has the remarkable ability to cross three tight human barriers: the intestinal barrier, the blood–brain barrier, and the fetoplacental barrier. At the cellular level, L. monocytogenes invades host cells, in which it is able to survive and replicate within the cytoplasm. Many reviews have been written on several aspects of Listeria–host interactions, ranging from bacterial entry into cells to adaptation to the intracellular environment. This review focuses on new striking findings regarding LLO and its roles during infection.
Listeriolysin O: the Swiss army knife of Listeria. Trends Microbiol. 29 May 2012
Listeriolysin O (LLO) is a toxin produced by Listeria monocytogenes, an opportunistic bacterial pathogen responsible for the disease listeriosis. This disease starts with the ingestion of contaminated foods and mainly affects immunocompromised individuals, newborns, and pregnant women. In the laboratory, L. monocytogenes is used as a model organism to study processes such as cell invasion, intracellular survival, and cell-to-cell spreading, as this Gram-positive bacterium has evolved elaborate molecular strategies to subvert host cell functions. LLO is a major virulence factor originally shown to be crucial for bacterial escape from the internalization vacuole after entry into cells. However, recent studies are revisiting the role of LLO during infection and are revealing new insights into the action of LLO, in particular before bacterial entry. These latest findings along with their impact on the infectious process will be discussed.