Difference between revisions of "Yersinia"
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| + | ===Overview=== | ||
| + | *Cause [[Intestine Pathogens - Pathology|intestinal disease]] in animals and are important zoonoses | ||
| + | *10 species of which [[Yersinia pestis|''Y. pestis'']], [[Yersinia pseudotuberculosis|''Y. pseudotuberculosis]] and [[Yersinia enterocolitica|''Y. enterocolitica'']] are pathogenic to animals and humans; [[Yersinia pestis|''Y. pestis'']] is the most pathogenic | ||
| + | *Rodents provide a reservoir of [[Yersinia pestis|''Y. pestis'']], which is the cause of human plague; fleas transmit the infection to other animals and humans | ||
| + | *[[Yersinia pseudotuberculosis|''Y. pseudotuberculosis'']] and [[Yersinia enterocolitica|''Y. enterocolitica'']] reside in the intestine of domestic and wild animals and birds | ||
| + | *Birds may cause mechanical transfer of the organisms | ||
| + | |||
| + | |||
| + | ===Characteristics=== | ||
| + | |||
| + | *Enterobacteria, but grow more slowly and at lower temperatures than other enterobacteria | ||
| + | *Gram negative, non-spore forming, facultative anaerobes - rods or colibacilli | ||
| + | *Non-lactose fermentors | ||
| + | *Facultative intracellular pathogens | ||
| + | *Show bipolar staining in Giemsa-stained smears from animal tissue | ||
| + | *Pathogenic strains identified by serotyping and biotyping | ||
| + | |||
| + | |||
| + | ===Pathogenesis=== | ||
| + | |||
| + | *''Y. enterocolitica and [[Yersinia pseudotuberculosis|''Y. pseudotuberculosis'']] enter the intestinal mucosa via M cells of the Peyer's patches | ||
| + | *Engulfed by macrphages in the mucosa | ||
| + | *All three invasive species are facultative intracellular organisms and grow inside macrophages | ||
| + | *Plasmid and chromosomal-encoded virulence factors required for survival and multiplication in macrophages | ||
| + | *Survive in phagolysosomes and do not interfere with degranulation or lysosomal fusion | ||
| + | *Resistant to macrophage killing mechanisms | ||
| + | *Antiphagocytic proteins secreted by the organisms interfere with host [[Neutrophils - WikiBlood|neutrophils]] | ||
| + | *[[Yersinia pestis|''Y. pestis'']] is more invasive than the other species and also possesses and antiphagocytic capsule and a plasminogen activator which aids systemic spread; endotoxin also contributes to its pathogenicity | ||
| + | *Transport within macrophages to mesenteric lymph nodes | ||
| + | *Replication in lymph nodes and development of necrotic lesions, with neutrophil invasion | ||
| + | *The bacteria destroy the macrophages causing septicaemia | ||
| + | |||
| + | |||
| + | ===Clinical infections=== | ||
| + | |||
| + | *''[[Yersinia pestis]]'' | ||
| + | |||
| + | *''[[Yersinia pseudotuberculosis]]'' | ||
| + | **Less virulent than ''Y. pestis'' but closely related | ||
| + | **Mainly infect animals | ||
| + | **One plasmid, required for virulence | ||
| + | **Sporadic cases of pseudotuberculosis in animals and man | ||
| + | **Wild birds and rodents provide a reservoir of infection by harbouring the the pathogen in their intestinal tract | ||
| + | **Sources include food and water contaminated by faeces | ||
| + | **Pseudotuberculosis (caseous abscesses) in rodents, guinea pigs, cats, turkeys | ||
| + | **Epidymo-orchitis in rams | ||
| + | **Abortion in goats | ||
| + | **Occasional infections in pigs, cattle, sheep | ||
| + | **Multiplication in macrophages leads to granuloma formation | ||
| + | **Granulomas occur in the gut wall and mesenteric lymph nodes | ||
| + | **Occasional spread from the mesenteric lymph nodes to the liver and [[Spleen - Anatomy & Physiology|spleen]] | ||
| + | *''[[Yersinia enterocolitica]]'' | ||
| + | **Pathogen of animals and humans | ||
| + | **Found in intestinal tract and oral cavity of animals, eg. pigs, leading to infection of humans via contaminated carcasses | ||
| + | **Enterocolitis in man which lasts 2-3 weeks or develops into a chronic form | ||
| + | **Enteric disease in farmed deer | ||
| + | **Ileitis, gastroenteritis, mesenteric adenitis | ||
| + | **Pathogenicity related to a heat stable enterotoxin | ||
| + | |||
| + | |||
| + | ===Diagnosis=== | ||
| + | |||
| + | *''Yersinia'' species grow on blood agar and MacConkey agar at room temperature. | ||
| + | *''Y. pseudotuberculosis'' and ''Y. enerocolica'' are motile, unlike ''Y. pestis'' | ||
| + | *Biochemical tests to identify particular species | ||
| + | *Specific fluorescent antibody staining of lymph node aspirates to identify ''Y. pestis'' | ||
| + | |||
| + | |||
| + | ===Control=== | ||
| + | |||
| + | *Control ''Y. pestis'' by controlling rodent population and flea control of cats | ||
| + | *Control of other ''Yersinia'' species difficult due to their ubiquity | ||
| + | |||
| + | |||
| + | ===Treatment=== | ||
| + | |||
| + | *Euthanase or isolate animals suspected of ''Y. pestis'' infection; Streptomycin, doxycycline, gentamicin or chloramphinol | ||
| + | *Long-acting tetracyclines, trimethoprim-sulphonamides, aminoglycosides and chloramphicol effective against ''Y. pseudotuberculosis'' and ''Y. enterocolica'' | ||
Revision as of 13:37, 12 May 2010
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This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing. |
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Overview
- Cause intestinal disease in animals and are important zoonoses
- 10 species of which Y. pestis, Y. pseudotuberculosis and Y. enterocolitica are pathogenic to animals and humans; Y. pestis is the most pathogenic
- Rodents provide a reservoir of Y. pestis, which is the cause of human plague; fleas transmit the infection to other animals and humans
- Y. pseudotuberculosis and Y. enterocolitica reside in the intestine of domestic and wild animals and birds
- Birds may cause mechanical transfer of the organisms
Characteristics
- Enterobacteria, but grow more slowly and at lower temperatures than other enterobacteria
- Gram negative, non-spore forming, facultative anaerobes - rods or colibacilli
- Non-lactose fermentors
- Facultative intracellular pathogens
- Show bipolar staining in Giemsa-stained smears from animal tissue
- Pathogenic strains identified by serotyping and biotyping
Pathogenesis
- Y. enterocolitica and Y. pseudotuberculosis enter the intestinal mucosa via M cells of the Peyer's patches
- Engulfed by macrphages in the mucosa
- All three invasive species are facultative intracellular organisms and grow inside macrophages
- Plasmid and chromosomal-encoded virulence factors required for survival and multiplication in macrophages
- Survive in phagolysosomes and do not interfere with degranulation or lysosomal fusion
- Resistant to macrophage killing mechanisms
- Antiphagocytic proteins secreted by the organisms interfere with host neutrophils
- Y. pestis is more invasive than the other species and also possesses and antiphagocytic capsule and a plasminogen activator which aids systemic spread; endotoxin also contributes to its pathogenicity
- Transport within macrophages to mesenteric lymph nodes
- Replication in lymph nodes and development of necrotic lesions, with neutrophil invasion
- The bacteria destroy the macrophages causing septicaemia
Clinical infections
- Yersinia pseudotuberculosis
- Less virulent than Y. pestis but closely related
- Mainly infect animals
- One plasmid, required for virulence
- Sporadic cases of pseudotuberculosis in animals and man
- Wild birds and rodents provide a reservoir of infection by harbouring the the pathogen in their intestinal tract
- Sources include food and water contaminated by faeces
- Pseudotuberculosis (caseous abscesses) in rodents, guinea pigs, cats, turkeys
- Epidymo-orchitis in rams
- Abortion in goats
- Occasional infections in pigs, cattle, sheep
- Multiplication in macrophages leads to granuloma formation
- Granulomas occur in the gut wall and mesenteric lymph nodes
- Occasional spread from the mesenteric lymph nodes to the liver and spleen
- Yersinia enterocolitica
- Pathogen of animals and humans
- Found in intestinal tract and oral cavity of animals, eg. pigs, leading to infection of humans via contaminated carcasses
- Enterocolitis in man which lasts 2-3 weeks or develops into a chronic form
- Enteric disease in farmed deer
- Ileitis, gastroenteritis, mesenteric adenitis
- Pathogenicity related to a heat stable enterotoxin
Diagnosis
- Yersinia species grow on blood agar and MacConkey agar at room temperature.
- Y. pseudotuberculosis and Y. enerocolica are motile, unlike Y. pestis
- Biochemical tests to identify particular species
- Specific fluorescent antibody staining of lymph node aspirates to identify Y. pestis
Control
- Control Y. pestis by controlling rodent population and flea control of cats
- Control of other Yersinia species difficult due to their ubiquity
Treatment
- Euthanase or isolate animals suspected of Y. pestis infection; Streptomycin, doxycycline, gentamicin or chloramphinol
- Long-acting tetracyclines, trimethoprim-sulphonamides, aminoglycosides and chloramphicol effective against Y. pseudotuberculosis and Y. enterocolica