Difference between revisions of "Actinobacillus pleuropneumoniae"
Jump to navigation
Jump to search
Line 22: | Line 22: | ||
*Causative agent: ''[[Actinobacillus pleuropneumoniae]]'' | *Causative agent: ''[[Actinobacillus pleuropneumoniae]]'' | ||
− | *Expolsive outbreaks of [[ | + | *Expolsive outbreaks of [[Pneumonia Overview#Infectious causes of pneumonia|pneumonia]] |
*Spread by direct contact and aerosol | *Spread by direct contact and aerosol | ||
*Lesions | *Lesions |
Revision as of 18:35, 19 February 2011
- Contagious Porcine Pleuropneumonia especially of pigs under 6 months
- Endemic in UK
- 12 serotypes causing the same disease
- Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
- Pathogenesis and pathogenicity:
- Virulent strains possess capsules which are antiphagocytic and immunogenic
- Fimbriae allow the bacteria to attach to cells of the respiratory tract
- Damaged neutrophils in the lungs produce lytic enzymes
- The sustained inflammatory response causes tissue necrosis
- Lungs consolidated and necrotic with fibrinous pleuisy at post mortem
- Produce three cytotoxins which belong to the repeats-in-structural-toxin (RTX) cytolysin family
- RTX toxins:
- Several peptide repeats within the molecules
- Produced by various Gram-negative bacteria
- Possess four contiguous genes, A, B, C and D
- A is the structural gene; B and D are required for secretion; C allows post-translational activation of the gene product of A into a functional product
- ApxI is a strong haemolysin with cytolytic activity
- ApxII is a weak haemolysin
- ApxIII is a cytotoxin
- Different Actinobacillus pleuropneumonia serotypes secrete a particular combination of toxins; American serotypes secrete ApxI and II; European serotypes secrete ApxII and III
- Toxins introduce pores into cell membranes
- Causative agent: Actinobacillus pleuropneumoniae
- Expolsive outbreaks of pneumonia
- Spread by direct contact and aerosol
- Lesions
- Largely from toxin produced
- In diphragmatic lobes of the lungs
- Haemorrhage with fibrinous pleuritis
- Usually localised, sometimes generalised