MORGANELLA

SPECIES

MICROSCOPIC APPEARANCE

Gram Stain: Gram-negative.
Morphology: Straight rods.
Size: 0.6-0.7 micrometers by 1.0-1.7 micrometers.
Motility: Motile by peritrichous flagella, swarming does not occur.
Capsules: None.
Spores: None.
Other: Originally classified in the genus Proteus as Proteus morganii .

MACROSCOPIC APPEARANCE

Some Morganella strains appear hemolytic when cultured on Blood Agar, while others produce a reddish-brown pigmentation.

KEY BIOCHEMICAL REACTIONS

METABOLIC PROPERTIES

Facultatively anaerobic. Chemoorganotrophic, having both fermentative and respiratory type metabolism. Acid production from mannose, but gas is not produced.

HABITAT

Intestinal and feces pathogen of man, other mammals, and reptiles.

PATHOGENICITY

There is considerable evidence that Morganella species play a pathogenic role in urinary tract infections, particularly for those of nosocomial origin. It is an opportunistic secondary invaders rather than a primary pathogen at other sites and has been isolated from bacteremias, respiratory tract, and wound infections.

RECOMMENDED MEDIA

For culture: Tryptic Soy Agar (TSA), Blood Agar 5%.
For selective isolation: MacConkey Agar, EMB Agar, Selenite Broth, Tetrathionate Broth.
For maintenance: Tryptic Soy Agar for short-term maintenance and lyophilization for long-term preservation.

INCUBATION

Temperature: 35 degrees C.
Time: 18-24 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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