Phylum Proteobacteria, Class Gammaproteobacteria, Order Pseudomonadales, Family Moraxellaceae, Genus Moraxella, Moraxella
catarrhalis (Frosch and Kolle1896) Henriksen and Bøvre 1968.
Synonym: Branhamella catarrhalis (Frosch and Kolle 1896) Catlin 1970. Old synonyms: Mikrokkokus catarrhalis (sic) Frosch and
Kolle in Flügge 1896, Neisseria catarrhalis (Frosch and Kolle 1896) Holland 1920.
Gram-negative diplo-cocci, 0.6-1.0 μm. Division in two planes at right angles to each
other and tetrad formation may be observed. May be fimbriated. Nonmotile.
Colonies are approximately 2.0 mm in diameter in 48 h, opaque, hemispherical,
becoming considerably larger and convex, almost flat, on prolonged incubation. They
usually have a friable texture and can be shifted around and picked from the agar
without losing their semi-convex shape and without adherence to the agar. Hemolysis
is absent on sheep blood agar. In broth produce little turbidity, but with a granular
sediment and surface ring.
Optimum growth temperature 37 ºC. Can grow at 22 ºC, weak at 42 ºC. Growth occurs
on nutrient agar. No growth on MacConkey agar, Thayer-Martin medium or in minimal
medium containing ammonium and acetate.
Isolated from the human nasopharynx (the main habitat), inflammatory secretions of the middle ear and maxillary sinus, from
bronchial aspirate in bronchitis and pneumonia, and occasionally from systemic infections.
Susceptible to amoxicillin-clavulanic acid, cefixime, chloramphenicol, ciprofloxacin, and ofloxacin. Strains that produce
beta-lactamase are expected to be resistant to penicillin, ampicillin, amoxicillin, and piperacillin.
May be a cause of disease in both the upper and lower respiratory tracts in adult humans (pneumonia, sinusitis, tracheobronchitis),
endocarditis, otitits media, arthritis, septicaemia or meningitis. It is responsible for otitis media and sinusitis in children.
- Elliot Juni and Kjell Bovre. Order IX Pseudomonadales Orla-Jensen 1921, Family II Moraxellaceae Rossau, Van Landschoot,
Gillis and De Ley 1991 In: Bergey’s Manual of Systematic Bacteriology, Second edition,Vol two, part B, George M. Garrity (Editor-in-
Chief), pp. 411-442.
- B. Wesley Catlin. Transfer of the Organism Named Neisseria Catarrhalis to Branhamella Gen. Nov. Int J Syst Bacteriol April 1970
- Cees M. Verduin, Cees Hol, André Fleer, Hans van Dijk, and Alex van Belkum. Moraxella catarrhalis: from Emerging to Established
Pathogen. Clin Microbiol Rev. 2002 January; 15(1): 125–144.
- Gabriel Ionescu, Delia Berceanu-Vaduva: Cocobacili Gram negativi nefermentativi. In: (Eds.) Dumitru Buiuc, Marian Negut. Tratat
de microbiologie clinica, ed. a III-a, cap. 32.2, 787-795.
Positive results for alkaline phosphatase, catalase, esterase, lipase, extracellular deoxyribonuclease, oxidase, tributyrin hydrolysis &
Negative results for acid phosphatase, citrate utilization, gelatin liquefaction, urea hydrolysis, hydrogen sulfide, indole production,
phenylalanine deamination, Tween 80 hydrolysis. No acid is produced from carbohydrates.
(c) Costin Stoica