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I. Organism Information
A. Taxonomy Information
1. Species
a. Listeria monocytogenes
i. Taxonomy ID: 1639
ii. Description:
Listeria monocytogenes is a low G+C, Gram-positive bacteria that is closely related to Bacillus, Clostridium, Enterococcus, Streptococcus, and Staphylococcus. L. monocytogenes are facultativly anaerobic, catalase-positive rods of 0.4 by 1 to 1.5 µm that do not form spores, have no capsule, and are motile at 10 to 25 degrees Celcius. They can cause serious, localized and generalized infections in humans and a variety of other vertebrates, including domesticated and wild birds and mammals. Listeria microorganisms were discovered in 1924, at Cambridge University by E.G.D. Murray, R.A. Webb, and M.B.R. Swann as the etiological agent of a septicemic disease affecting rabbits and guinea pigs (1).
iii. Variants
Listeria monocytogenes serotype 1/2a
Taxonomy ID: 169963
Listeria monocytogenes serotype 4b
Taxonomy ID: 265669
B. Lifecycle and Morphology
1. Intracellular:
The intracellular phase of the life cycle involves early escape from the phagocytic vacuole, rapid multiplication within the cytoplasm, bacterially induced actin-based motility, and direct spread to neighboring cells, in which the cycle is reinitiated. This shelters the spread of Listeriae from the humoral immune system (1).
To contribute a blurb on lifecycle, serotypes or handling the organism in healthcare or laboratory facilities, please contact help@nmpdr.org Your contribution will be credited with a byline.
a. Shape:
Regular, short rods with rounded ends, 0.4 μm by 1 - 1.5 μm. Some cells may be curved. Cells occur singly, or in short chains. Cells may be arranged at an angle to each other to give V-forms or in groups lying parallel along the long axis (2).
b. Picture:

SEM image of Listeria in tissue by Elizabeth White, CDC
2. Environmental:
a. Picture:

SEM image of Listeria after 2 days growth at 20° C on a stainless steel surface (size bar is 10 μm) by P. Chavant, M. Hébraud, B. Martinie, INRA, Theix
C. Genome Summary
1. Genome of Listeria monocytogenes 4b F2365
a. Chromosome
i. RefSeq Accession Number: NC_002973
ii. Size: 2,905,187 bp
iii. Serotype 4b (genomic division II) isolate from contaminated cheese that caused a lethal outbreak of listeriosis in 1985.
2. Genome of Listeria monocytogenes 1/2a EGD-e
a. Chromosome
i. RefSeq Accession Number: NC_003210
3. Genome of Listeria monocytogenes 1/2a F6854
a. Chromosome
i. RefSeq Accession Number: NZ_AADQ00000000
ii. Size: 2,950,285 bp
iii. Serotype 1/2a
4. Genome of Listeria monocytogenes 4b H7858
a. Chromosome
i. RefSeq Accession Number: NZ_AADR00000000
ii. Size: 2,972,254 bp
iii. Serotype 4b
II. References
1. Vazquez-Boland JA, Kuhn M, Berche P, Chakraborty T, Dominguez-Bernal G, Goebel W, Gonzalez-Zorn B, Wehland J, Kreft J. (2001) Listeria pathogenesis and molecular virulence determinants. Clin Microbiol Rev. 14(3):584-640.
New Study Sheds Light On How Intracellular Pathogens Trigger The ... Science Daily (press release) - ScienceDaily (July 14, 2008) Disease-causing microbes like the food-borne bacterium Listeria monocytogenes specialize in invading and replicating inside ... |
Proper diet is even more important when eating for two Sauk Valley Newspapers, IL - Stay away from cheeses such as feta, brie, Camembert, blue-veined, and Mexican-style. These cheeses are unpasteurized and may cause Listeria infection. |
Wild Alaskan Smoked Salmon Recalled InjuryBoard.com, FL - It is feared that the salmon is contaminated with Listeria monocytogenes, which is an organism that can be deadly to children. ... |
Autophagic control of listeria through intracellular innate immune ... Nature.com (subscription), UK - ... induction of autophagy and that autophagy prevented the intracellular growth of Listeria monocytogenes and promoted host survival after this infection. ... |
Pathogen Genes Targeted In Studies To Protect Salad Veggies Science Daily (press release) - ScienceDaily (July 12, 2008) No one knows exactly how microbes like Listeria monocytogenes or Salmonella enterica can attach themselves to the bumpy ... |
EFSA publishes Salmonella hazard advice All about feed, Netherlands - According to the Panel, Salmonella is the major biological hazard for animal feed, with other bacteria such as Listeria (Listeria monocytogenes), ... |
![]() Lawyers and Settlements | Fred Pritzker: Litigating Food Borne Injury Cases Lawyers and Settlements - For example, in the Listeria case on the east coast I just mentioned, the outbreak strain of the Listeria was found in two different plants within 90 miles ... |
FDA warns against boguss cancer cures Gridley Herald, CA - Salmolux Inc. of Federal Way, WA, is recalling lot # 01418 of its Wild Alaskan Smoked Salmon Nova Lox due to the potential of contamination from Listeria ... |
LISTERIA CONTROL IN CONSUMER PROTEIN PRODUCTS Newswise (press release) - Newswise Most cases of Listeria occur at the deli counter rather than at the manufacturer, yet most of the federal government s sanitary guidelines are ... |
EPA approved antimicrobial could control listeria in food plants FoodProductionDaily.com, France - Listeriosis is a rare but potentially lethal infection that can kill vulnerable people, such as the elderly and pregnant women, as well as those suffering ... |