Test 2- Moraxella Flashcards
The genus Moraxella
Many Species
- Of importance
- M. bovis
- M. bovoculi
- M. ovis
Humans
• M. catarrhalis: pneumonia
Moraxella bovis General
- Gram-negative pleomorphic rods
- Generally in pairs or short chains
- Non-motile
- Catalase & oxidase positive
- Obligate symbiotic
- Obligate pathogenic
• Quite resistant in the environment
Moraxella bovis
Moraxella bovis disease in bovines
• Infectious bovine keratoconjunctivitis or ‘Pink eye’
- Serous to purulent conjunctivitis and keratitis
- Highly infectious/contagious
- Mainly young animals
Moraxella bovis Virulence
• Essential: fimbriae
———-Adhesion to host cell (eye): conjunctival and corneal epithelial cells
- Capsule
- LPS
• Exotoxins
——-Cytotoxin
——- Pore forming toxin
Moraxella bovis Pathogenesis
- Specific attachment of bacteria to conjunctival/corneal epithelia
- Production of toxin
1 and 2 Destroy Tissue
- Inflammation
- further growth and production of toxins
3 and 4 Further damage
- Increased susceptibility for other pathogens
- Non infectious damage: dust,…
5 and 6 cause Irreversible eye damage
Moraxella bovis Predisposing factors
- Young cattle
- Flies
- Eye irritation
—– Dust
—— Sun,…
• Bovine herpesvirus 1 infection (IBR)
- Mycoplasma bovoculi
- Listeria monocytogenes
Moraxella bovis transmission
• Direct contact with infected animal
• Flies
Moraxella bovis Diagnosis
• Immunofluorescence
- Culture
- Blood agar plates at 35°C
- Hemolytic colonies
- Oxidase +, non fermenting
• PCR
Moraxella bovis
Prevention and treatment
• Prevention:
—– Flies
- —- Dust
- —- Elimination of other predisposing factors
—– No vaccine to date
• Treatment
• Antibiotics: local and eventually systemic
—– Tetracycline,florfenicol
• Corticosteroids
—– If inflammation is serious only because it can lower immunity
In separate stable (evt. dark) no flies/dust: transmission will decrease
M. bovoculi
- Cocci
- Diplococci
- Associated with keratoconjunctivitis in bovines
—– much more rare
M. ovis
- Cocci
- Associated with keratoconjunctivitis in bovines
• Associated with pneumonia in bovines
—– much more rare