Bacteria Genomes - LISTERIA MONOCYTOGENES

Listeria monocytogenes is a pathogenic bacterium that is food-borne and causes listeriosis (a serious infection caused by eating food contaminated with the bacterium) which is fatal in 20 to 30 percent of cases. It can cause septicaemia, meningitis, encephalitis and abortions, and targets certain at risk sectors of the population (the elderly, new-born babies and pregnant women). Listeriosis can manifest itself sporadically, but it can also lead to epidemics through the ingestion of contaminated food.

L. monocytogenes has been associated with such foods as raw milk, supposedly pasteurised fluid milk, cheeses (particularly soft-ripened varieties), ice cream, raw vegetables, fermented raw-meat sausages, raw and cooked poultry, raw meats (all types), and raw and smoked fish.

Listeria bacteria can grow slowly at refrigeration temperatures and can also grow in packages with little or no oxygen. Listeria colonies are small, smooth and blueish-grey. Their optimum growth temperature is between 30 and 37 degrees celsius, but growth can occur at temperatures as low as 4 degrees celsius. Listeria are Gram-positive , facultatively anaerobic, short, regular non-sporing rod-shaped bacteria that use host-produced actin filaments for motility within the host cell. The bacteria propel themselves through the cytoplasm of an infected cell using a tail composed of actin. It has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources.

References:

Science 294(5543):849-852(2001).
Nucleic Acids Res. 32(8):2386-2395(2004)
http://www.about-listeria.com/main.html
http://www.bacteriamuseum.org/species/listeria.shtml
http://vm.cfsan.fda.gov/
http://biology.kenyon.edu/Microbial_Biorealm/bacteria/gram-positive/listeria/listeria.htm#ecology