MORAXELLA (SUBGENUS - BRANHAMELLA)

27 plus species including:

SPECIES

MICROSCOPIC APPEARANCE

Gram Stain: Gram-negative with a tendency to resist discoloration.
Morphology: Short and plump rods, frequently approaching a coccus shape. Occurring in pairs or short chains.
Size: 1.0-1.5 micrometers by 1.5-2.5 micrometers.
Motility: Swimming motility is absent but surface bound "twitching" motility may be present.
Capsules: Some encapsulation does occur.
Spores: None.

MACROSCOPIC APPEARANCE

Colonies appear smooth, translucent and semi-opaque. Pitting occurs on Nutrient Agar.

KEY BIOCHEMICAL REACTIONS

METABOLIC PROPERTIES

Aerobic. Chemoorganotrophic, having both a fermentative and respiratory type metabolism. Most species are nutritionally fastidious. No acid is produced from glucose and other carbohydrates.

HABITAT

Parasites of mucous membranes of humans and animals.

PATHOGENICITY

Rare agents of infection. The organisms are generally considered not to be of high pathogenicity and are usually harmless parasites of the mucous membranes.

RECOMMENDED MEDIA

For culture: Nutrient Agar, Blood Agar, and Tryptose Blood Agar, Chocolate Agar.
For selective isolation: None described.
For maintenance: Lyophilization for long-term storage.

INCUBATION

Temperature: 30-37 degrees C.
Time: 24-48 hours.
Atmosphere: Aerobic with or without increased CO 2 (5-10%).
pH: 5.0-9.0.

REFERENCES

1. Holt, J.G., et al. 1994. Bergey's Manual of Determinative Bacteriology , 9th ed. Williams & Wilkins, Baltimore, MD.

2. Holt, J.G., et al. 1986. Bergey's Manual of Systemic Bacteriology , Vol. I & II. Williams & Wilkins, Baltimore, MD.

3. The Oxoid Vade-Mecum of Microbiology . 1993. Unipath Ltd., Basingstoke, UK.

4. Murray, P.R., et al. 1995. Manual of Clinical Microbiology , 6th ed. American Society for Microbiology, Washington, D.C.

5. Internet: www.hardlink.com /Bacterial Database Search, February, 1998.

6. Hensyl, B.R., et al. 1990. Stedman's Medical Dictionary , 25th ed. Williams & Wilkins, Baltimore, MD.

7. Koneman, et al. 1997. Color Atlas and Textbook of Diagnostic Microbiology , 5th ed. Lippincott, Philadelphia, PA.


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