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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
©2012 GoogleEggs recalled in Colorado for possible listeria contamination - Fox 31 KDVR.com
![]() Michigan Business Review - MLive.com | Eggs recalled in Colorado for possible listeria contamination Fox 31 KDVR.com Listeria monocytogenes is an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Although healthy individuals may suffer only short-term symptoms such as ... Egg recall in 34 states over Listeria concerns Recall of possible listeria tainted eggs expands to include another Michigan ... Eggs recalled in 34 states over listeria concerns |
Milford Bay Trout Farm recalls fillet over Listeria concerns - Globe and Mail
Milford Bay Trout Farm recalls fillet over Listeria concerns Globe and Mail Milford Bay Trout Farm Inc. is recalling its Smoked Trout Fillet because the product may be contaminated with Listeria monocytogenes. The affected product was distributed in Ontario with best before dates of February 9, 2012 and February 10, 2012, ... HEALTH HAZARD ALERT CERTAIN MILFORD BAY SMOKED TROUT FILLET MAY CONTAIN ... CFIA/Health Hazard Alert: Certain Milford Bay Smoked Trout Fillet May Contain ... |
Company Recalls Egg Salad Sandwiches - WKRC TV Cincinnati
![]() NewsNet5.com | Company Recalls Egg Salad Sandwiches WKRC TV Cincinnati CINCINNATI (AP) - A company is recalling egg salad sandwiches in five states with the brand names Quick CafDe and Take Away CafDe because of possible listeria contamination. Greencore, USA - Cincinnati said Friday that it is recalling about 550 pounds ... Greencore, USA Cincinnati, Recalls Egg Salad Sandwiches with Brand Name ... Ohio firm recalls salads GH Foods recalls Cobb salad products |
Federal food safety surveillance program stalled - CBC.ca
![]() CBC.ca | Federal food safety surveillance program stalled CBC.ca Brown was one of thousands of people who became ill in 2008 after eating meat contaminated with listeria from a Toronto-area Maple Leaf Foods processing plant. At least 23 people died. During the crisis, the Canadian Food Inspection Agency attracted ... |
Cantaloupe Listeria Outbreak Still Claiming Victims - Food Safety News
Cantaloupe Listeria Outbreak Still Claiming Victims Food Safety News by Gretchen Goetz Feb 02, 2012 One more victim of the nationwide outbreak of Listeria infection linked to Colorado cantaloupes died this week, bringing the death toll up to 32. When the epidemic was declared over in December of last year, ... US: Cantaloupe listeria claims yet another life |
Listeria Cantaloupe Outbreak Tied to Flawed Safety Practice - BusinessWeek
![]() USA TODAY | Listeria Cantaloupe Outbreak Tied to Flawed Safety Practice BusinessWeek 10 (Bloomberg) -- A listeria outbreak that killed 30 people and sickened another 146 may have been avoided if a Colorado cantaloupe processor had followed US guidelines and washed the fruit in chlorinated water, a congressional investigation found. Report on listeria outbreak blames Jensen Farms and third-party auditors Deadly Listeria Outbreak Fault Of Many, Investigators Say Gear, water likely cause of listeria outbreak: report |
Grower linked to listeria fined on migrant housing - Fox News
Grower linked to listeria fined on migrant housing Fox News DENVER A Colorado cantaloupe grower whose farm was identified by federal authorities as the source of a listeria outbreak that killed 30 people last year was fined by the US Department of Labor on Thursday for failing to provide safe migrant worker ... |
(credit: Phran Novelli) - CBS Local
![]() CBS Local | (credit: Phran Novelli) CBS Local DEERFIELD, NJ (CBS) A New Jersey company is recalling certain types of lettuce after concerns arose about possible listeria contamination. F&S Produce Company, Inc. located in Deerfield, NJ, recalled 389 pounds of Cobb and spinach salads that contain ... New Jersey Firm Recalls Cobb and Spinach Salads Due to Possible Listeria ... |
Michigan Firm Recalls Salad Products for Possible Listeria Contamination - eNews Park Forest
![]() Food Poison Journal | Michigan Firm Recalls Salad Products for Possible Listeria Contamination eNews Park Forest The salads contain eggs that are the subject of an FDA recall due to contamination with Listeria monocytogenes, the US Department of Agriculture's Food Safety and Inspection Service (FSIS) announced today. The salad products were produced on Jan. Sub sandwiches recalled on listeria fears Spartan Stores recalls 8 deli products for possible listeria 18th Street Deli Julienne Salad Recalled for Listeria |
As listeria scare fades, Canada cutting food safety inspections - Toronto Star
![]() Globe and Mail | As listeria scare fades, Canada cutting food safety inspections Toronto Star Resources will sunset for listeriosis, and for increased frequency of food inspection in meat processing establishments, says a line in the latest report on planning and priorities from the Canadian Food Inspection Agency. Union warns of cuts to federal food inspection Meat inspectors' union warns of food-safety program cuts Food Safety Spending in Canada Might Be Cut |