Aggregatibacter segnis
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Aggregatibacter,  
Aggregatibacter  segnis  
(Kilian 1977) comb. nov. Norskov-Lauritsen and Kilian 2006.
Old synonyms:
Haemophilus segnis  Kilian 1977.
Gram-negative, pleomorphic rods, often filamentous forms.
Colonies on chocolate agar are convex, smooth or granular, greyish white and
opaque, 0.5 mm in diameter within 48 hours.  Non-hemolytic. Growth in broth and
fermentation media is slow, and reactions are negative or weakly positive. Growth on
Mac Conkey agar is  negative.
Require V-factor but not X-factor. CO
2 is not required for growth, but CO2 enhances
growth for some strains.
It is a regular member of the human oral flora, particularly in dental plaque, and can be isolated from the pharynx. Occasionally
isolated from human infections (endocarditis).
Occasionally isolated from human infections (endocarditis)
  1. 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.
  2. Mary P.E. Slack, 2006. Haemophilus. In: Topley & Wilson’s Microbiology and Microbial Infections, 10 edition, Vol. 2, Bacteriology,
    Edward Arnold Ltd.
  3. N. Mihancea si colab., 2009. Identificarea genului Haemophilus. In: Tratat de microbiologie clinica, D. Buiuc, M. Negut, Ed.
    Medicala, Bucuresti, 797-809.
  4. 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.
  5. Zinnemann K., Biberstein E. L., 1975.Genus Haemophilus. In: Buchanan R.E., Gibbons N.E. (Ed.) Bergey’s Manual of
    Determinative Bacteriology, 8th-edition, Williams & Wilkins, 364-370.
  6. Niels Nørskov-Lauritsen & Mogens Kilian: Reclassification of Actinobacillus actinomycetemcomitans, Haemophilus  aphrophilus,
    Haemophilus paraphrophilus and Haemophilus segnis as Aggregatibacter actinomycetemcomitans gen. nov., comb. nov.,
    Aggregatibacter aphrophilus comb. nov. and Aggregatibacter segnis comb. nov., and emended description of Aggregatibacter
    aphrophilus to include V factor-dependent and V factor-independent isolates. International Journal of Systematic and Evolutionary
    Microbiology (2006), 56, 2135–2146.
Positive results for nitrates reduction, alkaline phosphatase, acid production (weak) from D(-) fructose , D(+) galactose, D(+) glucose
(without gas), maltose, and sucrose.

Negative results for oxidase, H
2S production, urease, arginine dehydrolase, lysine decarboxylase, ornithine decarboxylase, indole
production, acid production from: glycerol, xylitol, L(+) arabinose, D(+) xylose, Dulcitol, meso-inositol, mannitol, D(-) sorbitol, trehalose,
raffinose, inulin, esculin, salicin, D(+) mannose, L(+) rhamnose, L(-) sorbose, cellobiose, lactose, and D(+) melibiose.

Variable results for catalase, ONPG, and alpha-glucosidase.
(c) Costin Stoica
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