Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Mannheimia,
Mannheimia varigena Angen, Mutters, Caugant, Olsen and Bisgaard 1999.
Biovar 1 (ornithine decarboxylase positive and correspond to M. haemolytica biogroup 6, Bisgaard Taxon 36 and Bisgaard Taxon 15
biovars 1) and biovar 2 (ornithine decarboxylase negative and correspond to Bisgaard Taxon 15 biovars 2).
Historical synonyms: M. haemolytica biogroup 6 (Bisgaard and Mutters, 1986), Bisgaard Taxon 36, Bisgaard Taxon 15 biovars 1,
Bisgaard Taxon 15 biovars 2.
Gram-negative, nonmotile, small rods or coccobacilli.
Colonies are regular, smooth, and graysh on blood agar; 1-2 mm in diameter. Most
strains are hemolytic on bovine blood agar. Growth on MacConkey is negative.
Strains of M. varigena have been isolated from ruminants (oral cavity, rumen and intestines, and from pneumonia, mastitis, and
septicemia in cattle) and pigs (upper respiratory tract, and some isolates have been associated with septicemia, enteritis and
Strains of M. varigena have been isolated from pneumonia, mastitis, and septicemia in cattle.
Biovar 2 was isolated from pigs; isolates from pigs have been associated with septicemia, enteritis and pneumonia.
The type strain was isolated from a bovine with pneumonia.
- R. Mutters, H. Christensen, M. Bisgaard, 2004. Genus I. Pasteurella. In: Bergey’s Manual of Systematic Bacteriology, Second
edition,Vol two, part B, George M. Garrity (Editor-in-Chief), pp. 857-866.
- 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.
Positive results for nitrates reduction, oxidase, alkaline phosphatase, catalase, ONPG,
acid production from: L(+) arabinose, mannitol, D(-) fructose, D(+) glucose (without
gas), sucrose, glycerol, L(-) fucose & D(+) galactose.
Negative results for gelatinase, H2S production (TSI), Voges-Proskauer, urease, arginine dehydrolase, indole, lysine decarboxylase,
alpha-glucosidase, citrate (Simmons), acid production from: xylitol, L(-) xylose, dulcitol, D(-) sorbitol, D(+) mannose, L(-) sorbose,
trehalose, inulin, esculin & D(+) melibiose.
Variable results for ornithine decarboxylase (+/ biovar 1 and -/biovar 2), acid production from: D(-) arabinose, meso-inositol, raffinose,
dextrin, salicin, lactose & maltose.
(c) Costin Stoica