BROCHOTHRIX

SPECIES

Brochothrix campestris
Brochothrix thermosphacta

MICROSCOPIC APPEARANCE

Gram Stain: Gram-positive.
Morphology: Regular, unbranched rods.
Size: 0.6-0.7 micrometers by 1.0-2.0 micrometers.
Motility: Non-motile. They appear singly, in chains or in long, filamentous chains that fold into knotted masses.
Capsules: No.
Spores: No.
Other: Coccoid forms appear in old cultures.

MACROSCOPIC APPEARANCE

Colonies are opaque, non-pigmented and non-hemolytic. Typical colonies are 0.75-1.0 millimeter in diameter.

METABOLIC PROPERTIES

Facultatively anaerobic. Seldom pigmented. Mesophilic and chemoorganoheterotrophic. Brochothrix spp. only grow in complex media. The major fermentation product from glucose is L(+)-lactate acid.

KEY BIOCHEMICAL REACTIONS

HABITAT

Widely distributed in the environment, Brochothrix spp. is a common spoilage organism of meat and meat products stored at chilled temperatures.

PATHOGENICITY

These organisms are of low pathogenicity and generally require a major break in the host's immunological defenses to cause significant infection. There is no evidence that B. thermosphacta is pathogenic. It is an economically important meat-spoilage organism because it grows in a wide variety of meats and meat products and produces malodorous metabolic end products which make affected meat unpalatable.

RECOMMENDED MEDIA

For culture: Nutrient Agar, Blood Agar 5%.
For selective isolation: STAA Agar (2) ( Brochothrix thermosphacta ).
For maintenance: Nutrient Agar, Blood Agar 5%. Also in Brucella with Glycerol for long-term storage at -70 degrees C.

INCUBATION

Temperature: 20-25 degrees C.
Time: 48 hours.
Atmosphere: Aerobic and facultatively anaerobic.
pH: 7.0, optimum growth range 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.


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