Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Actinobacillus,
Actinobacillus lignieresii Brumpt 1910.
Historical synonyms: Actinobacilo Lignieres and Spitz 1902, Bacterium purifaciens Christiansen 1917.
Small and rod-shaped cells or coccobacillary. In media with fermentable carbohydrates, long bacillary or filamentous forms can be
seen and shorter bacillary or filamentous forms are on media containing blood or serum. Small granules can be lying at the pole of
the bacillary or filamentous form, this gives the characteristic “Morse code” form.
Rods: 1.15-1.25 x 0.4 µm, nonmotile, nonsporing. Cells stain easily with carbol fuchsin;Gram-negative, may show bipolar staining.
Slime, but not a capsule, can be demonstrated in wet India ink preparations.
Viscous colonies, 1-2 mm diameter, on primary isolation; the sticky aspect is lost with
subcultivation. The colony size increase up to 4 mm upon prolonged cultivation.
Colonies are nonhemolytic and V-factor independent. Broth cultures are turbid with
little deposit. Growth is improved by the addition of serum. Aerobic, facultatively
anaerobic. Growth occurs between 20 and 39 ºC. Optimum temperature 37 ºC. Not
growth at 44 ºC. Growth on MacConkey is positive.
Has a commensal role in the mouth and rumen of healthy cattle and sheep.
Invasion and establishment within tissue usually promote the transition from commensalisms to pathogenicity, the actinobacilli often
operate as opportunists.
Produces actinobacillosis in cattle and sheep.There is variation in pathogenicity between strains, some of which do not cause
disease at all. In cattle, chronic granulomatous lesions are found on the tongue (“wooden tongue”) and in other soft tissues of the
head and upper alimentary tract. Lymph nodes in the region are affected. Skin, lungs, testes, and mammary glands are most
commonly affected in sheep.
Has been isolated from an epidural abscess, an intramandibular phlegmon and an enlarged tongue of horses
Tongue lesions in dogs and oviduct lesions in ducks. Infections in humans bitten by horses and sheep.
Subcutaneous injection into cattle may produce an abcess similar to that occurring naturally.
Efforts to produce specific lesions in laboratory animals have usually failed. Chick and mice embryous may be more susceptible ;
mice that are injected intraperitoneally and chick embryos inoculated into the allantoic cavity usually die. Limphadenitis in lab rats.
- Olsen I., MØller K., 2004. Genus II. Actinobacillus. In: Bergey’s Manual of Systematic Bacteriology, Second edition,Vol two, part B,
George M. Garrity (Editor-in-Chief), pp. 866-883.
- W.M. Janda, R. Mutters, 2006. Pasteurella, Mannheimia, Actinobacillus, Eikenella, Kingella, Capnocytophaga, and other
miscellaneous Gram-negative rods. In: Topley & Wilson’s Microbiology and Microbial Infections, 10 edition, Vol. 2, Bacteriology,
Edward Arnold Ltd.
- J. G.Holt et al., 1994. Bergey’s Manual of Determinative Bacteriology, 9-edition, Williams & Wilkins.
- Carmen Pinzaru, 2009. Identificarea genurilor Pasteurella, Mannheimia, Actinobacillus.In:D.Buiuc, M.Negut (Ed.),Tratat de
Microbiologie Clinica, Ed. Medicala, Bucuresti, 859-868.
- Buchanan R.E., Gibbons N.E. (co-editors), 1975. Bergey’s Manual of Determinative Bacteriology, eight edition, The Williams &
Wilkins Company, Baltimore.
The best fermentation with carbohydrates is obtained in a peptone_Lemco base with
1% carbohydrate and bromothymol blue as an indicator (Holmes, 1998).
Nitrates reduction, oxidase, alkaline phosphatase, H2S, urease, D(+) xylose, mannitol,
D(-) fructose, D(+) galactose, D(+) glucose (acid), D(+) mannose, maltose, sucrose
(saccharose) & dextrin = positive. Lactose is positive but reaction is delayed, 5-7 days.
Gelatinase, arginine dehydrolase, lysine decarboxylase, ornithine decarboxylase,
indole, dulcitol, meso-inositol, L(+) rhamnose, cellobiose, melibiose, trehalose,
inulin, esculin, salicin, sorbose & gas from D(+) glucose = negative.
Catalase, Voges-Proskauer, glycerol, L(+) arabinose, D(-) sorbitol, ONPG & raffinose = variable.
(c) Costin Stoica