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PasteurellaRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Gammaproteobacteria -> Pasteurellales -> Pasteurellaceae -> Pasteurella OVERVIEW: Coccobacilli or rods, generally, 0.3–1.0 × 1.0–2.0 µm. Depending on the growth stage, cells occur singly, in pairs, or less frequently in short chains. Sometimes threads or filaments are formed resulting in marked pleomorphism. Pleomorphism occurs mainly in old cultures. Gram negative, although bipolar staining often can be observed. In tissues, P. multocida often shows bipolar staining with Giemsa or Wright's stain. Not acid fast. Endospores are not formed. Nonmotile. Aerobic to microaerophilic or facultatively anaerobic. Chemoorganotrophic with both oxidative and fermentative types of metabolism. Electron transport system is cytochrome-based with oxygen, nitrate, or fumarate as the terminal electron acceptor. Nitrate reductase is produced. Oxidase positive, alkaline phosphatase positive, and almost always catalase positive. Most species are V-factor and X-factor independent, but V-factor-requiring strains do occur. Even after specific growth factors have been provided, complex media may be required to obtain better growth. Optimum growth temperature 35–37°C. Arginine dihydrolase and lysine decarboxylase negative. Gelatin is not liquefied within 48 h. No growth occurs in Simmons citrate medium. Acid is produced from d-glucose, d-galactose, d-fructose, d-mannose, and sucrose. Acid is not produced from l-sorbose, l-rhamnose, m-inositol, and adonitol. Parasitic in vertebrates, particularly mammals and birds. Genome molecular weights range from 1.4 × 109 to 1.9 × 109.The mol% G + C of the DNA is: 37.7–45.9.Type species: Pasteurella multocida
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