23 - Pathogenic Yersinia Species Flashcards
1
Q
Yersinia genus
A
- Enterobacteriaceae family
- Gram negative, rod shaped bacillus
- Consists of 14 species
2
Q
Three well recognized pathogenic species in humans
A
- Yersinia enterocolitica
- Yersinia pseudotuberculosis
- Yersinia pestis
3
Q
Yersinia enterocolitica
A
- Enteric, causes Yersiniosis
- self-limiting gastroenteritis to terminal ileitis, mesenteric
lymphadenitis, and septicemia in immunocompromised
hosts - Transmitted fecal orally via contaminated milk or pork, person to person transmission is rare
- Pigs are main reservoir
4
Q
Six biogroups of Yersinia enterocolitica
A
1A, 1B, 2, 3, 4 and 5
5
Q
Yersinia pseudotuberculosis
A
- Acute gastroenteritis, mesenteric lymphadenitis and diarrhoea, also mimicks acute or subacute appendicitis
- Found in rodents, rabbits, deer, birds
- Survives in water and environment
- Growth at 4ºC
- 21 different serological groups
6
Q
Yersinia pestis
A
- Evolved from Y. pseudotuberculosis
- Causes Plague, a severe, acute,
and rapidly progressing febrile illness with significant mortality rates - Sylvatic life cycle
7
Q
Three disease manifestations of Yersinia pestis
A
- Bubonic
- Septicaemic
- Pneumonic
8
Q
Transmission of plague
A
- Bite of infected fleas
- Inhaling infected droplets expelled by coughing
- Direct contact with contaminated tissue or body fluid
9
Q
Symptoms of Bubonic plague
A
- Headache, nausea, aching joints, and a general feeling of
malaise - Buboes (painful inflammation at lymph nodes in neck)
- Hemorrhaging under the skin,
causing black splotches - 50% Death if untreated
10
Q
Pneumonic plague
A
- Bacteria enter the lung
- Inhalation of contaminated droplets
- Symptoms include coughing, expulsion of slimy sputum with traces of blood, free flowing red sputum at later stages
- 95% death if untreated
11
Q
Septicemic plague
A
- When bacteria enter the bloodstream
- Symptoms include high fever, rash, gangrene, leading to
respiratory failure - Fatality is 100%
- Can cause disseminated intravascular coagulation, small blood clots throughout body that can result in ischemic necrosis
12
Q
Virulence determinants of Yersinia
A
- Plasminogen activator
- Murine toxin
- F1 capsular antigen
- T3SS
13
Q
Plasminogen activator (Pla protease)
A
- Transmembrane protease
- Encoded on plasmid pPCP1
- Has protease activity that interacts and cleaves host proteins targets
- Targets important in response to infection (e.g. coagulation and fibrin clot)
- Allows bacteria to disseminate from bite site and subversion of immune response
14
Q
Murine toxin
A
- Phospholipase D (PLD) activity
- Encoded by plasmid pMT1
- Required for survival in midgut of rat flea
- Intracellular PLD activity protects Y.pestis from a cytotoxic digestion product of blood plasma in the flea gut.
- Enables colonisation of the flea midgut
- Acquisition of PLD precipitated the transition of Y. pestis
to obligate arthropod-borne transmission
15
Q
F1 capsular antigen
A
- Encoded by plasmid pMT1
- Forms a surface located polypeptide capsule at 37°C growth
- Antiphagocytic activity
- Good vaccine candidate
- Important but not essential for virulence
