Listeria monocytogenes - Wikipedia, the free encyclopedia "Listeria monocytogenes is a Gram-positive bacterium, in the division Firmicutes, named for Joseph Lister. It is motile by means of flagella. It can also move within eukaryotic cells by polymerizing actin comet tails with a protein called ActA. Some studies suggest that 1 to 10% of humans may carry L. monocytogenes in their intestines.

Researchers have found L. monocytogenes in at least 37 mammalian species, both domesticated and feral, as well as in at least 17 species of birds and possibly in some species of fish and shellfish. Laboratories can isolate L. monocytogenes from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree."  ¶ 1:19 AM