Category:Bordetella species

Bordetella species

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▼ Bordetella species
Bordetella species - Overview
Bordetella avium
Bordetella bronchiseptica

B. bronchiseptica infects a wide range of animal species worldwide
B. avium resticted to birds
Normal inhabitants of upper respiratory tract
Cause repsiratory diseases including rhinitis, tracheitis, bronchitis and bronchiolitis
Exogenous or endogenous infection
Poor survival in the environment
Transmission between animals
Young animals particularly susceptible
Predisposing factors include stress and concurrent infections
High morbidity; low mortality

Gram negative rods
Strict aerobes
Grow slowly
Catalase and oxidase positive
Non-lactose fermentors
Grow on MacConkey agar
Toxigenic strains agglutinate mammalian red blood cells
Identical S form LPS in all strains of B. bronchiseptica - 1 diagnostic antigen
B. bronchiseptica haemolytic, whereas B. avium not
Affinity for ciliated respiratory epithelium

Use pathogenicity factors such as filamentous haemagglutanin (only B. bronchiseptica), fimbriae and pertactin to adhere to ciliated respiratory epithelium
Produce toxins:
- Adenylate cyclase (leucocyte toxin - kills phagocytes) (only B. bronchiseptica)
- Tracheal cytotoxin (inhibits DNA synthesis in ciliated cells)
- Dermonecrotic toxin
Pathogenicity factors activated by environment and genetic changes
Regulatory locus, BvgAS, mediates the activation
Phase variation: genetic switch of Bvg locus allows transciption of pathogenicity factors
Phenotypic modulation: temperature, magnesium ions and nicotinic acid affect expression of pathogenicity factors
Bvg positive allows expression of pathogenicity factors and toxins and colonisation
Bvg negative may allow survival in the environment with production of flagellae
Mucosal IgA prevent attachment of bacteria to cilia, but clearance from the respiratory tract may take weeks
Carrier animals are a source of infection

The following 3 pages are in this category, out of 3 total.