KURTHIA

3 plus species including:

SPECIES

Kurthia gibsonii
Kurthia zopfii

MICROSCOPIC APPEARANCE

Gram Stain: Positive. Not acid-fast.
Morphology: Regular or unbranched rods with rounded ends. Older cultures (over 2 days) are usually composed of coccoid cells.
Size: 0.8-1.2 micrometers by 2.0-4.0 micrometers, usually occurring in long, parallel chains and filaments.
Motility: The rods are usually motile by peritrichal flagella. Non-motile strains do occur; the coccoidal cells are non-motile.
Capsules: None.
Spores: None.

MACROSCOPIC APPEARANCE

Growth on yeast nutrient agar shows rhizoid colonies, with loops and whorls of chains of rods at the edge "Medusa-head appearance", and on nutrient gelatin slants the growth has a "bird's feather" appearance.

KEY BIOCHEMICAL REACTIONS

METABOLIC PROPERTIES

Kurthia species are aerobic, Chemoorganotrophic, with a strictly respiratory metabolism. They are not fermentative. Kurthia spp. produce very weak acidity from glucose or carbohydrates in peptone media. Amino acids, alcohols, fatty acids are used as carbon sources.

HABITAT

Kurthia species are widely distributed in the environment and are common in feces of farm animals, milk, soil and surface waters, meat and meat products after cold storage.

PATHOGENICITY

Kurthia species are primarily non-pathogenic. Although a number of strains of bacteria identified as " Kurthia spp." have been isolated from various clinical materials, most commonly from the feces of patients suffering from diarrhea, there is no evidence of pathogenicity in authentic numbers of the genus. (2) However, Kurthia spp. have been implicated as opportunistic pathogens reported to cause endocarditis.

RECOMMENDED MEDIA

For culture: Nutrient Gelatin, Nutrient Broth, Yeast Nutrient Agar, or Yeast Nutrient Gelatin. (2)
For selective isolation: Yeast Nutrient Agar with Nystatin.
For maintenance: Yeast Nutrient Agar slants for up to 6 months. Lyophilization is required for long-term storage.

INCUBATION

Temperature: 25-30 degrees C.
Time: 4-5 days.
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 , 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.

8. Howard, B.J., et al. 1994. Clinical and Pathogenic Microbiology, 2nd ed. Mosby, St. Louis, IL.


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