FLAVOBACTERIUM

40 plus species including:

SPECIES

Flavobacterium aquatile
Flavobacterium balustinum
Flavobacterium breve
Flavobacterium gleum
Flavobacterium indologenes
Flavobacterium meningosepticum
Flavobacterium mizutaii
Flavobacterium multivorum
Flavobacterium odoratum
Flavobacterium spiritivorum
Flavobacterium thalpophilum
Flavobacterium yabuuchiae

MICROSCOPIC APPEARANCE

Gram Stain: Negative.
Morphology: Rods with straight, parallel sides and rounded ends.
Size: 0.5 micrometers by 1.0-3.0 micrometers.
Motility: Non-motile.
Spores: Endospores are not formed.
Capsules: No.
Other: Intracellular granules of poly-beta-hydroxybutyrate are absent.

MACROSCOPIC APPEARANCE

Growth on solid media is slow. The colonies are typically translucent and pigmented yellow to orange. Usually 1-2 micrometers in diameter, they are convex or low convex, smooth and shiny with entire edges. Non-pigmented and occasionally opaque strains occur.

METABOLIC PROPERTIES

Aerobic, having a strictly respiratory type of metabolism. Chemoorganotrophic. Acid, but no gases are produced from carbohydrates. Most do not ferment sugar or glucose.

KEY BIOCHEMICAL REACTIONS

HABITAT

Widely distributed in soil and water; found in raw meats, milk and other foods, also found in hospital environments and in other human clinical material.

PATHOGENICITY

Found in humans and cats as pathogenic. Flavobacterium meningosepticum is well recognized as a cause of neonatal meningitis and such infections have a poor prognosis. Meningitis due to F. meningosepticum in adults is rare, as is septicemia, and all the patients in whom it has been described had underlying diseases predisposing to Gram-negative infection. This species may also cause pneumonia in both infants and adults. Colonization of the respiratory tract in compromised hosts may occur under endemic situations. The pathogenicity for man of other Flavobacterium species is less well documented but cases of meningitis, bacteremia, and upper respiratory tract colonization of seriously ill patients have been attributed to group IIb.

RECOMMENDED MEDIA

For culture: Columbia Blood Agar, Nutrient Agar, or Tryptic Soy Agar.
For selective isolation: None described. (1,2)
For maintenance: Brucella with 20% Glycerol may be used for long-term storage at -70 degrees C. Lyophilization may be used for preservation.

INCUBATION

Temperature: 35 degrees C. and environmental isolates at 30 degrees C.
Time: May take several (5-7) days to produce colonies.
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.


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