Phylum Proteobacteria, Class Gammaproteobacteria, Order Pseudomonadales, Family Moraxellaceae, Genus Moraxella, Moraxella
bovis (Hauduroy, Ehringer, Urbain, Guillot and Magrou 1937) Murray 1948.
Old synonyms: Haemophilus bovis Hauduroy et al. 1937, Moraxella duplex des bovidés Lwoff 1939.
Gram-negative rods, variable in shape (0.5-1.5 x 2.0 μm), size and arrangement.
Encapsulated. Nonmotile. The cells are often fimbriated and show “twitching motility”.
Freshly isolated strains form hemispherical to flat colonies (1 mm in diameter
in 48 h) on blood agar; they corrode the agar and often show surface spreading.
Nonfimbriated variants occur spontaneously in cultures and form noncorroding,
nonspreading colonies which are convex and usually larger than their corroding
counterparts (often 3.0 mm after 48 h), and have a butyrous consistency. Fimbriated
cells of collection strains may also form large colonies, but these may be less
corroding than the colonies of fresh isolates. Broth: Slow growth; slight turbidity;
considerable sediment. Litmus milk: alkaline, partial coagulation.
Most bovine strains produce distinct hemolytic zones around colonies. Nutritionally
fastidious. No growth on MacConkey agar.Optimum temperature for growth 35-37 ºC.
Isolated from bovine keratoconjunctivitis, but has also been isolated from unaffected eyes and the nasal cavity of cattle, the eyes
of sheep and mice, but not the eyes of rats, rabbits, or guinea pigs. M. bovis has been found to survive up to 3 days on insect legs.
It is the most common cause of infectious bovine keratoconjunctivitis (IBK), an epidemic and highly contagious disease causing
temporary or even permanent blindness, predominantly in calves. Pathogenicity factors: adhesins, leukotoxin, phosphoamidase,
phosphatase, hyaluronidase, lipases, pili (fimbriae) production, a hemolysin or cytolysin. Experimental infection cannot be
reproduced with non-hemolytic and non-fimbriated strains.
Not pathogenic for laboratory animals.
- Elliot Juni and Kjell Bovre: Order IX Pseudomonadales Orla-Jensen 1921, Family II Moraxellaceae Rossau, Van Landschoot,
Gillis and De Ley 1991 In: Bergey’s Manual of Systematic Bacteriology, Second edition,Vol two, part B, George M. Garrity (Editor-in-
Chief), pp. 411-442.
- John P. Hays. Chapter 3.3.38. The Genus Moraxella. Prokaryotes (2006) 6:958–987.
- Robert S. Breed, E. G. D. Murray, Nathan R. Smith. Genus VII. Moraxella Lwoff 1939, in Bergey's Manual of Determinative
Bacteriology. Seventh Edition, pp 419-421, 1957.
- Helgomar Raducanescu, Valeria Bica-Popii: Bacteriologie Veterinara (1986), 137-138.
- B. Wesley Catlin. NOTES. Branhamaceae fam. nov., a Proposed Family To Accommodate the Genera Branhamella and Moraxella.
International Journal Of Systematic Bacteriology Apr,. 1991, Vol. 41, No. 2, p. 320-323.
M. bovis can be distinguished from M. boevrei by the reduction of nitrate.
Positive results for catalase, esterase, gelatin hydrolysis, oxidase, proteolysis on Loeffler slants, Tween 80 hydrolysis & acid
phosphatase (weak). Can liquefy the coagulated serum.
Negative results for alkaline phosphatase, DN-ase, H2S production, indole production, nitrates reduction, phenylalanine deaminase &
urease. No acid is produced from glucose or other carbohydrates.
(c) Costin Stoica