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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.
Listeria - Google News
©2010 GoogleWhole Foods Market to recall farm cheese - WireUpdate
Whole Foods Market to recall farm cheese WireUpdate Consumption of food contaminated with Listeria monocytogenes can cause serious and sometimes fatal infections in young children, frail or elderly people, ... Good night! Morningland recalls 68957 pounds of raw milk cheese Morningland Dairy Recalls Raw-Milk Cheese Sold in 48 States Morningland Dairy recalls cheese |
New York Cheese Maker Expands Recall - AHN All Headline News
New York Cheese Maker Expands Recall AHN All Headline News 24 regarding cheese that may be infected with Listeria monocytogenes. Azteca Linda Corp. announced last week a recall of its Queso Fresco, or Fresh White ... Cheese Recalled For Listeria Contamination Azteca Linda Corp. Expands Recall of Queso Fresco Because of Possible Health Risk Azteca Linda Expands Cheese Recall |
380000 pounds of Walmart deli meat recalled due to possible Listeria contamination - Examiner.com
![]() CNN International | 380000 pounds of Walmart deli meat recalled due to possible Listeria contamination Examiner.com According to Medicine Net, the official definition of Listeria is: "A group of bacteria capable of causing miscarriage (spontaneous abortion), ... Deli Meats Sold to Wal-Mart Are Recalled 380000 Pounds of Walmart Meat Recalled For Listeria Walmart Recalls Deli Meat for Listeria |
Deadly Meat? 10 Things to Avoid - CBS News
Deadly Meat? 10 Things to Avoid CBS News But with salmonella, Listeria, and other food borne pathogens stalking consumers from coast to coast, you'll need more than the smell test to ensure you ... |
Exotic cheese tests positive for listeria in RI - BusinessWeek
![]() Eat, Drink and Be (blog) | Exotic cheese tests positive for listeria in RI BusinessWeek Beardsworth says there are no confirmed cases of listeria in human that are linked to the product. It was not immediately clear how widely the cheese has ... Exotic cheese tests positive for listeria in RI RI Dept. of Health Warns of Cheese Product Linked to Listeria Brooklyn Food Manufacturer Recalls Two Soft Cheeses |
U.S. dairy recalls cheese in listeria scare - Windsor Star
![]() The News Chronicle (blog) | U.S. dairy recalls cheese in listeria scare Windsor Star Eating food contaminated with Listeria can cause listeriosis, a potentially fatal disease characterized by fever, muscle aches and nausea, according to the ... 68957 pounds of cheese recalled by Mo. dairy Another Recall: Cheese and Still Counting sns-health-raw-cheese-recalled-nationwide |
Cheese Recalled for Listeria, Staph Contamination - Food Safety News
![]() fox4kc.com | Cheese Recalled for Listeria, Staph Contamination Food Safety News The California Department of Food and Agriculture notified Missouri agriculture officials that cheese produced at the dairy contained traces of Listeria ... Missouri Dairy's Raw Milk Cheese Production Stopped Due to Listeria and Staph Production of Missouri dairy's cheese stopped Bacteria found in California cheese products |
Queseria Chipilo Recalls Cheese products Over Listeria Fears - Newsinferno.com
Queseria Chipilo Recalls Cheese products Over Listeria Fears Newsinferno.com The Cheese products may be contaminated with Listeria monocytogenes, a dangerous, sometimes deadly organism. A complete listing of the recalled products can ... Queseria Chipilo Recalls Cheese Products Queseria Chipilo Recalls Cheese Products Because Of Possible Health Risk |
Product recalls: cheese products, shell eggs - The Associated Press
![]() TopNews Singapore (press release) | Product recalls: cheese products, shell eggs The Associated Press ... _Queseria Chipilo of Passaic, NJ, is recalling certain packages of cheese products because they may be contaminated with Listeria monocytogenes. ... Williamsburg Cheese Manufacturer Issues Recall Total recall! Williamsburg cheese factory pulls back tainted grub Queseria Chipilo Recalls Tainted Cheese Products |
Green grosser: Fresh Express recalls salad mixes - New York Daily News
![]() New York Daily News | Green grosser: Fresh Express recalls salad mixes New York Daily News The company is voluntarily recalling 2825 cases of Veggie Lovers Salad due to a potential contamination with the disease-causing bacterium Listeria ... UPDATED: Fresh Express recalls salad mix because of listeria concern Fresh Express Recalls Salads for Listeria Starwatch Consumer Salad recalls; anti-seizure drug |