Positive results for nitrates reduction, oxidase, alkaline phosphatase, H2S production, acid production from: D(+) glucose (gas is
variable), D(-) fructose, D(+) galactose, D(+) mannose, maltose & sucrose.
Negative results for arginine dehydrolase, alpha-glucosidase, acid production from: xylitol, L(+) arabinose, D(+) xylose, dulcitol, meso-
inositol, mannitol, D(-) sorbitol, L(+) rhamnose, L(-) sorbose, cellobiose, lactose, D(+) melibiose, trehalose, inulin, esculin & salicin.
Variable results for ONPG, catalase, urease (biovars I, V, VI, VIII -; biovars II,III,IV,VII +), lysine decarboxylase, ornithine decarboxylase
(biovars III, V, VII, VIII -; biovars I,II, IV,VI +), indole (biovars I, II, III, V -; biovars IV,VI,VII +), acid production from: glycerol & raffinose.
Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Haemophilus,
Haemophilus parainfluenzae, eight biovars (I-VIII, based on three biochemical characteristics: indole production, urease and
ornithine decarboxylase activities). Biovar V is phenotypically similar to H. segnis and H. paraphrophilus, so it is not clear if this strains
indeed belong to the H. parainfluenzae.
Gram-negative, pleomorphic rods, filamentous forms. Some strains possess capsule.
Growth on chocolate agar is similar to that of H. parahaemolyticus: colonies are
grayish white or yellowish opaque, 1-2 mm in diameter after 24 h. Some strains
produce flat, smooth colonies with entire edge, others show serrated edge and
others produce rough wrinkled colonies. Growth in broth media may be granulated.
Nonhemolytic (some strains show week beta-hemolysis, but the property is lost by
Aerobic, facultatively anaerobic, require V-factor, but not X-factor for growth. CO2 is not
required for growth. Growth on Mac Conkey agar is negative.
Bacteria is ubiquitous in the human oral cavity and pharynx and may be present in the normal vaginal flora. The majority of human
isolates can be assigned to biovars I-III.
Organisms closely resembling H. parainfluenzae have been isolated from monkeys, swine, rabbits and rats.
Germs have low pathogenicity and is occasionally implicated in endocarditis and lower respiratory tract infections in humans.
- Mogens Kilian, 2004. Genus III. Haemophilus In: Bergey’s Manual of Systematic Bacteriology, Second edition, Vol two, part B,
George M. Garrity (Editor-in-Chief), pp. 883-904.
- Mary P.E. Slack, 2006. Haemophilus. In: Topley & Wilson’s Microbiology and Microbial Infections, 10 edition, Vol. 2, Bacteriology,
Edward Arnold Ltd.
- J. G. Holt et al., 1994. Facultatively Anaerobic Gram-Negative Rods. Subgroup 3. Family Pasteurellaceae. In: Begey’s Manual of
Determinative Bacteriology, 9th-edition, Williams & Wilkins, pp 194-196.
- Zinnemann K., Biberstein E.L., 1975. Genus Haemophilus. In: Buchanan R.E., Gibbons N.E. (co-editors), Bergey’s Manual of
Determinative Bacteriology, eight edition, The Williams & Wilkins Company, Baltimore.
(c) Costin Stoica