SERRATIA

13 plus species including:

SPECIES

MICROSCOPIC APPEARANCE

Gram Stain: Gram-negative.
Morphology: Straight rods with rounded ends.
Size: 0.5-0.8 micrometers by 0.9-2.0 micrometers.
Motility: Usually motile by peritrichous flagella.
Capsules: None.
Spores: None.

MACROSCOPIC APPEARANCE

Colonies often appear opaque, somewhat iridescent, white, pink, magenta, or red. Cultures can produce two kinds of odors, a fishy to urinary odor or a musty, potato-like odor.

KEY BIOCHEMICAL REACTIONS

METABOLIC PROPERTIES

Most strains DNAse-positive.
Facultatively anaerobic. Chemoorganotrophic, having both a fermentative and respiratory type metabolism. Ferments glucose and other carbohydrates with acid production, but no gas.

HABITAT

Widely distributed in the environment (soil, water, plants), digestive tracts of rodents and insects, and are opportunistic pathogens for hospitalized humans.

PATHOGENICITY

Serratia marcescens is an important cause of extraintestinal infections, having caused many nosomial outbreaks associated with blood transfusions, surgery, and the urinary tract. Also, Serratia spp. are known to cause Mastitis in cows and other animals.

RECOMMENDED MEDIA

For culture: Nutrient Agar, Standard Methods Agar or Tryptic Soy Agar (TSA).
For selective isolation: MacConkey Agar.
For maintenance: Nutrient Agar for short-term maintenance and Lyophilization for long-term storage.

INCUBATION

Temperature: 30-37 degrees C.
Time: 24-48 hours.
Atmosphere: Aerobic.
pH: 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.

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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