BREVIBACTERIUM

26 plus species including:

SPECIES

Brevibacterium casei
Brevibacterium epidermidis
Brevibacterium iodinum
Brevibacterium linens
Brevibacterium mcbrellneri

MICROSCOPIC APPEARANCE

Gram Stain: Positive. Non-acid-fast.
Morphology: Irregular rods. Coccoid forms with coryneform appearance. They are arranged singly or in pairs and often at an angle to give "V" formations. This organism segments into small cocci in older cultures.
Size: 0.6-1.2 micrometers by 1.5-6 micrometers.
Motility: Non-motile.
Capsules: Not typically, but seen on some species. Branching may occur, but a mycelium is not formed.
Spores: Non-sporeforming.
Other: Easily decolorized.

MACROSCOPIC APPEARANCE

Colonies are smooth and may be white to gray-white, yellow or orange-red depending on the species. Pigment production is light dependent. These organisms have a distinctive odor sometimes described as cheesy or body odor.

METABOLIC PROPERTIES

Strict aerobes. Chemoorganotrophs with a respiratory metabolism. Generally, biochemically inert toward carbohydrates, but proteolytically active; non-fermentative.

KEY BIOCHEMICAL REACTIONS

HABITAT

Saprophytes on skin, spoilage organisms in foods and dairy products.

PATHOGENICITY

These organisms are of low pathogenicity and are considered secondary invaders. They generally require a major break in the host's immunological defenses to cause significant infection. Brevibacterieae, in particular B. linens and B. casei , have been implicated in contributing to the aroma of various cheeses. Brevibacterieae may occur as spoilage organisms in foods and in the case of human skin surfaces, Brevibacterieae probably contribute to unpleasant boy odors. (2)

RECOMMENDED MEDIA

For culture: Nutrient Agar, Tryptic Soy Agar, and Blood Agar 5%.
For selective isolation: No specific selective media described. (1,2)
For maintenance: Nutrient Agar, Tryptic Soy Agar, Blood Agar 5% for short-term preservation and Brucella with Glycerol at -70 degrees C. or lyophilization may be used for long-term storage.

INCUBATION

Temperature: 20-30 degrees C.
Time: 48 hours.
Atmosphere: Aerobic.

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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