Listeria monocytogenes

Listeria monocytogenes is Gram-positive,Rod-shaped, motile facultative bacterium, have flagella.Is the leading causes of death from foodborne illness.It has 13 serotypes, including 1/2a, 1/2b, 1/2c, 3a, 3b,3c, 4a, 4ab, 4b, 4c, 4d, 4e, and 7. Majority of foodborne infections mainly associated with serotype 1/2a, 1/2b, and 4b. L.monocytogenes hardy show salt-tolerant and not only can survive in temperatures below 1°C growth has been also seen in these conditions, which show its persistence in food-manufacturing environments.The bacterium most commonly found in soil, water ,vegetable (decaying), raw foods.Outbreaks of listeriosis have been linked to a variety of foods such as meat and cheese especially linked to ready to eat food butter, cream hot dogs, deli meats, and paté) and dairy products made from unpasteurized milk Listeria is a bacterium that causes a serious infection ,around 300 deaths are caused by Listeria infection each year, according to estimates from a 2011 CDC report.

Organism Details:
Shape and Size
0.5 to 2 Ľm, Rod-shaped.
Genome Information
Listeria monoctyogenes is a Gram-positive Facultative bacterium. Listeria monoctyogenes strain J1926 chromosome ( GI:525934212) has a circular DNA chromosome of 2953708 bp It has 2,995genes and 2,899 coding proteins, Pseudo Genes: 11, rRNAs: 18 ( 5S, 16S, 23S ),,tRNAs: 67,Frameshifted Genes: 10. The GC content of Listeria monoctyogenes is about 38% and the percentage coding of the bacteria is about 96.08%. .
Food Source
Meat, Seafood,Fermented meat, sausages, Unpasteurized milk, Soft Cheeses made from unpasteurized milk,Raw fruits and vegetables, ,Ready to eat deli meats, Salads, , Hot dogs, Pre-packed sandwiches, Pâté, Butter, cooked sliced meats, cold-smoking Fish, coleslaw.
Pathological Factor
L. monocytogenes enters the human body through the gut, most often after ingestion of a contaminated food lead to the production of an exotoxin called listeriolysin O, Listeria monocytogenes toxin acts as a hemolysin, listeriolysin O (LLO) considered as SH-activated hemolysins,also produced by a number of other Gram-positive bacteria.Hemolysin gene is located on the chromosome with other virulence genes get regulated by a common promoter. Listeria monocytogenes has the ability to produce catalase and superoxide dismutase which neutralize the effects of the phagocytic oxidative burst which leads survival of the bacterium within the phagolysosome. L. monocytogenes produces two other hemolysins besides LLO: phosphatidylinositol-specific phospholipaseC (PI-PLC) and phosphatidylcholine-specific phospholipase C (PC-PLC). Unlike LLO, which lyses host cells by forming a pore in the cell membrane, these phospholipases disrupt membrane lipids such as phosphatidylinositol and phosphatidylcholine(lecithin). The bacterium also produces a Zn++ dependent protease which may act as some sort of exotoxin.
Disease
Mostly affect eldery person, pregnant women and newborn which have weakened immune system this may lead to cause listeriosis and deaths also.Despite of that infections can occur occasionally in healthy persons. Infections during pregnancy can lead to miscarriages, stillbirths, and infection of newborn infants. The initial symptoms are often fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. The illness may be mild and ill persons sometimes describe their illness as flu-like.If infection spreads to the nervous system, symptoms such as headache, stiff neck, confusion, loss of balance, or convulsions can occur. Babies can be born with Listeria if the mother eats contaminated food during pregnancy.The death rate among newborns with Listeria is 25 to 50 %.In pregnant women, however, even though the most usual symptom is a mild influenza-like illness without meningitis, infection of the fetus is extremely common and can lead to abortion, stillbirth, or delivery of an acutely ill infant.Listeriosis is a serious disease for humans; the overt form of the disease has ty greater than 25 percent and causes : Listeriosis Meningiti, Sepsticemia, Miscarriage,
Affected Body Organs
gastroenteritis
Classification
Kingdom Bacteria
Division Firmicutes
Class Bacilli
Order Bacillales
Family Listeriaceae
Genus Listeria
Specie L. monocytogenes