 | ||||||||||||||||||||||||||
HaemophilusRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Gammaproteobacteria -> Pasteurellales -> Pasteurellaceae -> Haemophilus OVERVIEW: Minute to medium-sized coccobacilli or rods, generally less than 1 µm in width and variable in length, sometimes forming threads or filaments and showing marked pleomorphism. Gram negative. Nonmotile. Aerobic or facultatively anaerobic. Require preformed growth factors present in blood, particularly X factor (protoporphyrin IX or protoheme) and/or V factor (nicotinamide adenine dinucleotide [NAD] or NAD phosphate [NADP]). Even after specific growth factors have been provided, growth is best on complex media. Optimum temperature, 35–37°C. Nitrates are reduced to or beyond nitrites. Oxidase and catalase reactions vary among strains. Chemoorganotrophic. All species can attack carbohydrates fermentatively, yielding acetic, lactic, and succinic acids as end products in glucose broth. Occur as obligate parasites on the mucous membranes of humans and a variety of animal species. Several 16S rRNA sequence signatures for the family Pasteurellaceae have been demonstrated, but none of these is specific for the genus Haemophilus as presently defined (Dewhirst et al., 1992).The mol% G + C of the DNA is: 37–44.Type species: Haemophilus influenzae This genus contains microbial species that can reside in the human gastrointestinal tract. [PMC 4262072]
| ||||||||||||||||||||||||||