Species/Subspecies: | Listeria monocytogenes | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Categories: | Zoonotic; causes hemolysis; motile; notifiable diseases and bacteria | |||||||||
Etymology: | Genus name: named after the British surgeon Lord Lister. Species epithet: monocyte producing. | |||||||||
Significance: | [Very important] | |||||||||
Taxonomy: | Class Bacilli Order Bacillales Family Listeriaceae Genus Listeria |
|||||||||
Type Strain: | ATCC 15313 = NCTC 10357. | |||||||||
Macromorphology (smell):
| Small (0,5- 1 mm in diameter) colonies, which can be crateriform on certain selective media. Produces a zone of hemolysis on blood agar. | |||||||||
Micromorphology: | Long thin rods (0.4-0.5 x 0.5-2 µm) in short chains. Motile by means of a few peritrichous flagella. L. monocytogenes also exhibits actin-based motility (see references 154 and 155 below). | |||||||||
Gram +/Gram -: | G+ | |||||||||
Metabolism: | Facultatively anaerobic. | |||||||||
Catalase/Oxidase: | +/- | |||||||||
Other Enzymes: | Esculinase +, lecithinase +, β-D-glucosidase +, hippuricase +, tryptophanase -, urease -. | |||||||||
Biochemical Tests: | Methyl red +, Voges-Proskauer +. | |||||||||
Fermentation of carbohydrates: | D-glucose + lactose + maltose ? L-rhamnose + sucrose - L-arabinose - cellobiose ? D-mannitol - salicin ? trehalose + glycerol + inulin ? raffinose ? D-sorbitol v starch - |
|||||||||
Spec. Char.: | Psychrotrophic. Can grow at 0-42°C and has temperature optimum at 30°C. Can survive at high NaCl concentrations. | |||||||||
Special Media:
| Colonies of Listeria sp. are blue-greenish on Brillians-Listeria-agar medium because they produce a β-glucosidase. There is also a precipitate around colonies of L. monocytogenes and pathogenic strains of L. ivanovii because they have a lecithinase (see the legend to the figure). | |||||||||
Disease: | Listeriosis. Encephalitis, abortion, septicemia and eye infections (ruminants). Food poisoining and abortion (humans).
|
|||||||||
Virulence Factors: | The membrane protein internalin, which induces cellular uptake of bacteria by phagocytosis. Listeriolysin O (a hemolysin), which makes it possible for the bacteria to escape from the phagosome before it fuses with a lysosome. The bacteria can polymerise actin by means of the protein Act A, which contributes to their intracellular mobility. | |||||||||
Genome Sequence: |
|
|||||||||
16S rRNA Seq.: |
| |||||||||
Taxonomy/phylogeny:
|
There are 21 species and subspecies described within the genus and all are very similar. L. monocytogenes and the nonpatogenic L. innocua have almost identical 16S rRNA sequences. | |||||||||
Legislation: | Listeriosis is zoonotic and a notifiable disease in Sweden. L. monocytogenes is classified as a potential biological weapon with the NIAID priority code B. | |||||||||
Comment: | Can invade cells and is facultatively intracellular (in monocytes). | |||||||||
Reference(s): | No. 31, 65, 154, 155 | |||||||||
Updated: | 2023-03-08 |
News |
---|
New names of bacterial phyla![]() The taxonomic category phylum was previously not regulated by the International Code of Nomenclature of Prokaryotes (ICNP), but now this has changed and it was decided to revise the names of bacterial phyla. All phyla must be written in italics (which has been done on VetBact also before) and have the ending -ota. Published 2023-03-01. Read more... |
The taxonomy of chlamydias Species within the family Chlamydiaceae were previously divided into two genera Chlamydia and Chlamydophila. However, the differences between these two genera were not that great and many research groups have not accepted this division. Therefore, the genus Chlamydophila has been returned to the genus Chlamydia and this change has now been incorporated in VetBact Published 2023-03-15. Read more... |