Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Actinobacillus,
Actinobacillus suis van Dorssen and Jaartsveld 1962.
Synonyms: equine strains of A. suis or hemolytic variants of A. equuli may constitute a separate group of organisms, provisionally
designated taxon 11 (Bisgaard etal., 1984).
Gram negative, long rods and filaments. Nonmotile. Nonsporulated.
Colonies are sticky and adhere to the medium ; in older colonies , a transparent
border zone is developed , giving the appearance of a fried egg. Hemolytic.
Viscous growth also occurs in nutrient broth, but is not so marked as in
Actinobacillus equuli. Nutrient agar and nutrient broth cultures die within 15 days at
40 ºC. Aerobic, facultatively anaerobic. Optimum temperature is 37 ºC. Growth on
MacConkey agar is positive. V-factor independent.
Opportunistic pathogen of swine of all ages and has been isolated from healthy pigs. Colonize the upper respiratory tract and the oral
cavity and the genital tract of horses and pigs.
Associated with septicemia and death in suckling and newly weaned piglets; septicemia in mature swine has also been reported.
Localized infections, such as endocarditis, polyarthritis, subcutaneous abscesses, and pneumonia, pleuritis , pericarditis, have also
been observed. Has been associated with pneumonia, pleuritis , pericarditis and polyarthritis in horses. One report of cat lung
Human infection is the result of a pig bite.
- 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. Begey’s Manual of Determinative Bacteriology, 9-edition, Williams & Wilkins.
- Daignault D., Chouinard L., Moller K., Ahrens S. & Higgins R. : Isolation of Actinobacillus suis from a cat's lung. Can. Vet. J., 1999,
Nitrates reduction, alkaline phosphatase, catalase, urease, esculin, glycerol, acid from
D(+) glucose, L(+) arabinose, D(+)xylose, D(-) fructose, D(+) galactose, D(+) mannose,
cellobiose, lactose, maltose, melibiose, sucrose (saccharose), trehalose, raffinose,
dextrin & salicin are positive.
Gelatinase, inulin, H2S, Voges-Proskauer, arginine dehydrolase, lysine decarboxylase, ornithine decarboxylase, indole, dulcitol,
meso-inositol, mannitol, D(-) sorbitol, L(+) rhamnose, L(-) sorbose & gas from D(+) glucose are negative.
Oxidase & ONPG tests are variable.
(c) Costin Stoica