Morexella Flashcards
Who causes infectious keratojunctivitis in cattle
Moraxella bovis
What is the morphology of Moraxella?
Diplobacillus
What is the gram staining of moraxella
Gram negative
What is the motility of moraxella
Non motile
What is the spore capability of Moraxella
Non sporeforming
What special surface structures does Moraxella bovis have?
Fimbriated (Piliated)
M. bovis pilus protein shares extensive homology with pilus protein of?
Bacteroides nodosus
What two forms do M. bovis pili exist in?
α (alpha) and β (beta) forms
How do M. bovis colonies appear on cow-blood agar?
Smooth, circular, translucent, grayish, and beta-hemolytic
Which colony forms of M. bovis are avirulent?
Smooth colonies (do not erode agar)
What growth requirements does M. bovis need?
Serum or blood for good growt
Can M. bovis ferment carbohydrates?
Does not ferment carbohydrates
What are the oxygen requirements of M. bovis?
Aerobic
What oxidase and catalase results does M. bovis show?
Oxidase-positive and catalase-variable
When does pinkeye most commonly occur in cattle?
Warmer months
What two environmental factors increase pinkeye risk?
Sunlight exposure to cornea and presence of face flies
How is M. bovis transmitted between cattle?
Direct contact and by flies (Musca autumnalis, M. domestica, Stomoxys calcitrans)
Where does M. bovis reside in carrier animals?
Nares and conjunctiva
Which cattle breeds are more resistant to pinkeye?
Bos indicus breeds
Why are Bos indicus breeds more resistant?
Hooded eyelids protect from sunlight
What virulence factor allows M. bovis to adhere to corneal cells?
Pili
What toxin causes the corneal lesions in pinkeye?
Dermonecrotic toxin
Are recovered cattle immune to reinfection?
Yes, resistant to reinfection
What antibodies are found in lacrimal secretions of immune cattle?
IgA, IgM, IgG
Which antibody provides longest-lasting protection?
IgA
