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Listeria monocytogenes
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
ii. Size: 2,944,528 bp
iii. Serotype 1/2a
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.
2. Bergey's Manual of Determinative Bacteriology, 9th edition. John G. Holt, Noel R. Krieg, Peter H.A. Sneath, James T. Staley, and Stanley T. Williams, editors. Baltimore: Williams and Wilkins, 1994, p.1235
3. Mascola L, Lieb L., Chiu J, Fannin SL and Linnan MJ. (1988) Listeriosis: an uncommon opportunistic infection in patients with acquired immunodeficiency syndrome. A report of five cases and a review of the literature. Am. J. Med. 84: 162-164.
4. Todars Online Textbook of Bacteriology
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