Pasteurella species and Mannheimia haemolytica

From WikiVet English
Jump to navigation Jump to search
BACK TO INFECTIOUS AGENTS AND PARASITES
BACK TO BACTERIA


Overview Pasteurella and Mannheimia

  • Common commensals of the upper respiratory tract and gastrointestinal tract mucosa of animals
  • Usually opportunistic organisms, causing disease during times of stress, low resistance or concurrent infection
  • Not part of the human bacterial flora
  • Small Gram-negative bacilli or coccobacilli
  • Facultative anaerobes
  • Oxidase-positive
  • May show bipolar staining with polychrome stains such as Wright's stain
  • Capsules contain acidic polysaccharides


Pasteurella Properties

  • Catarrhal odour
  • Produce endotoxins which cause host damage and death
  • Their capsules resist phagocytosis


Pasteurella multocida

  • Large grey colonies on blood agar
  • Not haemolytic
  • Do not grow on MacConkey
  • Five capsular serotypes, A,B,D,E and F
  • Primary and secondary pathogen
  • Responsible for secondary infections following primary viral and mycoplasmal infections, especially in the lungs, for example during Enzootic pneumonia of calves and pigs
  • Can cause vascular fragility, leading to haemorrhagic disease
  • Involved in subcutaneous abscesses due to cat bites


  • Typa A
    • Commensal in upper respiratory tract of animals in UK
    • Primary pathogen in avian cholera - a septicaemia in chickens and turkeys
    • Secondary pathogen commomly repsonsible for dog and cat bite wound infections in humans and animals
    • Feline pyothorax and cellulitis
    • Some strains involved in Atrophic rhinitis of pigs, and produce osteolytic toxin
    • Involved in 'Snuffles' in rabbits, a mucopurulent rhinosinitis
    • Can cause pneumonia and mastitis in sheep
    • Associated with pneumonic pasteurellosis in cattle, as well as enzootic pneumonia in calves
  • Type B
    • Causes Haemorrhagic Septicaemia of cattle in Southern Europe and Asia
  • Type E
    • Causes African Bovine Haemorrhagic Septicaemia

Pasteurella pneumotropica

  • Carried in nasopharynx of many small rodents
  • Causes pneumonia in rodents as a secondary disease

Pasteurella trehalosi

  • T biotypes - trehalose fermenters
  • Pneumonia in ruminants
  • Septicaemic pasteurellosis in feeder lambs
  • Mastitis in sheep

Pasteurella canis

  • Pneumonia in dogs
  • Occasionally infects wounds

Pasteurella caballi

  • Equine respiratory tract disease, usually in association with Streptococcus equi subspecies S. zooepidemicus
  • Equine peritonitis

Pasteurella aerogenes

  • Associated with gastroenteritis and abortion in swine


Mannheimia

Mannheimia haemolytica

  • Cause of epizootic pneumonia in cattle known as Shipping Fever, Transit Fever or pneumonic pasteurellosis (90% caused by Mannheimia haemolytica Biotype A, serotype 1 but also Pasteurella multocida
  • Usually secondary to viral infections such as parainfluenza - 3 or IBR, bacterial infections such as Mycoplasma or environmental stress
  • May contribute to Enzootic pneumonia of calves
  • Enzootic pneumonia in sheep
  • Peritonitis in sheep
  • Permeability types of pulmonary oedema
  • Septicaemia in young lambs
  • Causes gangrenous mastitis in sheep
  • Beta-haemolytic on blood agar
  • Grow weakly on MacConkey agar
  • Odourless
  • All are Mannheimia A biotypes (previously Pasterurella haemolytica)
  • Strains often produce a cytotoxin, known as leukotoxin, which kills leukocytes of ruminants
  • Leukotoxin is a member of the RTX group toxins, and is probably largely responsible for the pathogenicity of the bacteria in septicaemia and pneumonia

Mannheimia glucosida

  • Previously biotype A11
  • Respiratory condition of ruminants
Retrieved from "https://en.wikivet.net/index.php?title=Pasteurella_species_and_Mannheimia_haemolytica&oldid=28922"