PROTEUS

7 plus species including:

SPECIES

MICROSCOPIC APPEARANCE

Gram Stain: Gram-negative.
Morphology: Rods.
Size: 0.4-0.8 micrometers by 1.0-3.0 micrometers.
Motility: Motile by peritrichous flagella; often swarming.
Capsules: None.
Spores: None.

MACROSCOPIC APPEARANCE

Most strains swarm with periodic cycles of migration producing concentric zones or spread in a uniform film, over moist surfaces. Also, a distinguishable odor exists.

KEY BIOCHEMICAL REACTIONS

METABOLIC PROPERTIES

Facultatively anaerobic. Chemoorganotrophic, having both a respiratory and fermentative type metabolism.

HABITAT

Widely distributed in animals, birds, reptiles, soil sewage and polluted water. Also found in the intestines of humans. Approximately one quarter of the human population are intestinal carriers of Proteus and patients may become infected with their own flora (autoinfection). Infections may also be contacted through transmission of the bacteria from other patients or from a common reservoir. (2)

PATHOGENICITY

P . mirabilis is more frequently isolated from clinical specimens than is P . vulgaris and is one of the leading pathogens of the human urinary tract. Proteus urinary tract infections occur more commonly in infection-susceptible hospital patients with predisposing conditions such as catheterization, surgery or urological instrumentation of the tract. P . mirabilis urinary tract infections acquired outside of the hospital are often associated with an underlying condition such as diabetes or structural abnormalities of the tract. Proteus urinary tract infections may give rise to bacteremias that are difficult to treat and often fatal.

Neonatal umbilical stumps contaminated with Proteus bacteria may lead to highly fatal bacteremia and meningitis. Under suitable conditions Proteus bacteria may be opportunistic invaders and cause septic lesions at other sites of the body. They have been isolated from infections of wounds, burns, respiratory tract, eyes, ears and throat. (2)

RECOMMENDED MEDIA

For culture: Tryptic Soy Agar (TSA).
For selective isolation: MacConkey Agar, Hektoen Enteric (HE) Agar, XLD Agar, HardyCHROMâ„¢ UTI, and Tetrathionate Broth.
For maintenance: Tryptic Soy Agar, Brucella with 20% Glycerol or Skim Milk for storage at
-70 degrees C. Lyophilization may be used for preservation.

INCUBATION

Temperature: 35 degrees C.
Time: 16-24 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 , 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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