Phylum Actinobacteria, Class Actinobacteria, Subclass Actibacteridae, Order Actynomycetales, Suborder Actinomycinae, Family
Actinomycetaceae, Genus Actinomyces, Actinomyces hordeovulneris Buchanan, Scott, Gerencser, Beaman, Jang and Biberstein,
Gram-positive pleomorphic rods and filaments, 0.5-1.0 µm in diameter, some of which
On bovine blood agar the colonies are white, adherent and molar toothed, with a
tendency to shift to a conical, buttery, less adherent type upon passage, with 0.5-1.0
mm in diameter after 2 days at 37 ºC and 2 mm after 3 days. On clear media (TSA or
BHI agar supplemented with 10-20% fetal calf serum) microcolonies after 24 h of
incubation are filamentous. Growth is flocculant in TSB with 5% fetal calf serum.
Facultative anaerobic but require CO2 for growth. Most strains are non-haemolytic on
bovine blood agar; a few are haemolytic after 7 days.
Isolated from infections in dogs. Susceptible to penicillin, cephalothin, trimethoprim+sulfametoxazol and tetracycline.
Isolated from dog pleuritis, peritonitis, visceral abscesses, septic arthritis and recurrent localized infections often occurring secondary
to tissue-wandering foxtail awns.
Occasionally, Actinomyces viscosus and Actinomyces hordeovulneris were present in the same sample.
- Buchanan A.M., Scott J.L., Gerencser M.A., Beaman B.L., Jang S., and Biberstein E.L., 1984. Actinomyces hordeovulneris sp. nov.,
an agent of canine actinomycosis. Int. J. Syst. Bacteriol. Vol. 34, No. 4, 439-443.
Positive results for catalase, esculin hydrolysis, acid production from: cellobiose, D-glucose, lactose, maltose, mannose (weak
reaction), melibiose (weak reaction), raffinose (weak reaction), trehalose & xylose.
Negative results for nitrate reduction, urease, Voges-Proskauer test, acid production from: arabinose, glycerol, inositol, mannitol,
rhamnose & ribose.
(c) Costin Stoica