Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Actinomycetota, Class Actinomycetes, Order Actynomycetales, Suborder Actinomycinae, Family Actinomycetaceae, Genus
Actinomyces, Actinomyces georgiae Johnson, Moore, Kaneko and Moore, 1990.
Historical synonym: Actinomyces D08.
Gram-positive swellings rods, shorter and even coccoid in broth medium without a
fermentable carbohydrate, occurring in pairs and short chains, branching is seldom
seen. Non-motile. Non-spore-forming.
Colonies are round with entire edges, pulvinate, translucent / opaque, white / beige,
shiny, smooth, 0.5-2.0 mm in diameter on blood agar incubated anaerobically. Grows
well in peptone-yeast extract - glucose - Tween 80 broth with/without turbidity and
smooth/flaky/granular sediment that occasionally adheres to the bottom of the tube.
Alpha-haemolysis may occur. Facultative anaerobic. Grows at 37 ºC, optimally.
Isolated from the gingival crevices and accounts for 1.4% of human healthy periodontal flora (1990).
Isolated from patients with gingivitis and periodontitis.
- Johnson J.L., Moore L.V.H., Kaneko B. and Moore W.E.C., 1990. Actinomyces georgiae sp. nov. , Actinomyces gerencseriae sp.
nov. , Designation of Two Genospecies of Actinomyces naeslundii, and Inclusion of A. naeslundii serotypes II and III and
Actinomyces viscosus serotype II in A. naeslundii Genospecies 2. Int J Syst Bacteriol Vol. 40, No. 3, 273-286.
Positive results for esculin hydrolysis, acid production from: fructose, glucose, glycogen, lactose, maltose, rhamnose, ribose, starch,
sucrose and xylose.
Negative results for catalase, starch hydrolysis, urease, acid production from: amygdalin, arabinose, cellobiose, esculin, melibiose,
melezitose, raffinose, salicin, sorbitol and trehalose.
Variable results for nitrate reduction, gelatin hydrolysis, acid production from: glycerol, inositol, mannitol and mannose.
(c) Costin Stoica