Pasteurella species and Mannheimia haemolytica

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• Pasteurella multocida in Atrophic rhinitis of pigs and atrophic rhinitis
• Peritonitis in sheep
• Permeability types of pulmonary oedema.
• Can be secondary to IBR
• Causes 'Snuffles' in rabbits
• Manheimia haemolytica biotype A serotype 1 (90%) and Pasteurella multocida cause pneumonic pasteurellosis
• Pasteurellosis in pigs
• Can cause vascular fragility, leading to haemorrhagic disease.
• M. haemolytica and P. multocida may contribute to Enzootic pneumonia of calves
• Often follows parainfluenza - 3 infection of cattle
• P. haemolytica in enzootic pneumonia of lambs
• In pyothorax
• P. multocida in cellulitis in cats

Overview Pasteurella

• Common commensal 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
• Resist phagocytosis by their capsule
• Not part of the human bacterial flora

Pasteurella Properties

• Short Gram-negative bacilli or coccobacilli
• Oxidase-positive
• May show bipolar staining
• Catarrhal odour
• Produce endotoxins which cause host damage and death

Pasteurella multocida

• Large grey colonies on blood agar
• Not haemolytic
• Do not grow on MacConkey
• Four capsular serotypes, A,B,D,E and recently F
• Primary and secondary pathogen
• Responsible for secondary infections following primary viral and mycoplasmal infections, especially in the lungs, for example during pig enzootic pneumonia

• Typa A
  • Commensal in upper respiratory tract of animals in UK
  • Primary pathogen in fowl cholera - a septicaemia in chickens and turkeys
  • Secondary pathogen commomly repsonsible for dog and cat bite wound infections in humans and animals
  • Some strains involved in Atrophic rhinitis of pigs, and produce osteolytic toxin
  • Involved in 'Snuffles' in rabbits (Pateurellosis)

• Type B
  • Causes Haemorrhagic Septicaemia of cattle in Southern Europe and Asia

• Type D
  • Primary and secondary pathogen
  • Causes Atropic Rhinitis along with Bordetella bronchiseptica in pigs
  • Produces an osteolytic toxin, which stimulates osteoclasts, inducing bone resorption

• Type E
  • Causes African Bovine Haemorrhagic Septicaemia

Pasteurella pneumotropica

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

Mannheimia haemolytica

• Cause of epizootic pneumonia in cattle known as Shipping Fever, Transit Fever or pneumonic pasteurellosis
• Usually secondary to viral infections such as parainfluenza - 3 or IBR, or to mycoplasma
• Causes pasteurellosis in sheep
• Beta-haemolytic on blood agar
• Grow weakly on MacConkey agar
• All are Manheimia A biotypes
• 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

Mannheimia trehalosi

• T biotypes - trehalose fermenters