AEROCOCCUS

SPECIES

Aerococcus urinae
Aerococcus viridans

MICROSCOPIC APPEARANCE

Gram Stain: Gram-positive.
Morphology: Cocci. Tetrads are formed in liquid media.
Size: 1.0 - 2.0 micrometers in diameter.
Motility: Non-motile.
Capsules: No.
Spores: No.

MACROSCOPIC APPEARANCE

Growth on solid media is generally sparse. Colonies are small, semi-transparent, white or gray with a beaded appearance. Greening reaction is produced on blood agar presumably as a result of H 2 O 2 production.

METABOLIC PROPERTIES

Facultatively anaerobic. Chemoorganoheterotrophic with a respiratory type metabolism. Produces acid without gas from various carbohydrates.

KEY BIOCHEMICAL REACTIONS

HABITAT

Frequently isolated from two widely divergent sources: as a common airborne organism in hospital environments and as a marine organism causing a fatal disease of lobsters.

PATHOGENICITY

Opportunistic pathogen. Generally saprophytic but has been associated with human endocarditis. Causes a fatal disease in lobsters called gaffkemia. A. urinae , a new species, was recently implicated as a pathogen in patients predisposed to urinary tract infection.

RECOMMENDED MEDIA

For culture: Columbia Blood Agar, Blood Agar 5%, Tryptic Soy Agar, MRS Broth, or Brain Heart Infusion Broth (BHI).
For selective isolation: MacConkey Agar or Baird-Parker Agar.
For maintenance: Blood Agar 5%, Tryptic Soy Agar, or Brucella Broth with Glycerol.

INCUBATION

Temperature: 35 degrees C.
Time: 18 - 24 hours.
Atmosphere: Microaerophilic.

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 , Volumes 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.


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