General Information: This strain has numerous pathogenicity islands and genes as compared to the related non-pathogenic organism Listeria innocua. This organism, which causes listeriosis, is one of the leading causes of death from food-borne pathogens especially in pregnant women, newborns, the elderly, and immunocompromised individuals. It is found in environments such as decaying vegetable matter, sewage, water, and soil, and it can survive extremes of both temperatures (1-45 degrees C) and salt concentration marking it as an extremely dangerous food-born pathogen, especially on food that is not reheated. This organism is enteroinvasive, and utilizes an actin-based motility system by using a surface protein, ActA, that promotes actin polymerization, to spread intercellularly using the polymerized cytoskeletal protein as a "motor". There are 13 serovars associated with Listeria monocytogenes, and the serovar 4b strains are more commonly associated with invasive disease.