SALMONELLA

Two species divided into five "subgenera" and many hundreds of serovars, often named after place of origin, including:

SPECIES

Salmonella Subgroup I (includes most serotypes):

Salmonella Subgroup II:

Salmonella Subgroup IIIa:

Salmonella Subgroup IIIb:

Salmonella Subgroup IV:

Salmonella Subgroup V:

MICROSCOPIC APPEARANCE

Gram Stain: Negative.
Morphology: Straight rods.
Size: 0.7-1.5 micrometers by 2.0-5.0 micrometers.
Motility: Usually motility by peritrichous flagella, however non-motile mutants do occur, and one type ( Salmonella gallinarum / Salmonella pullorum ) is always non-motile.
Capsules: None.
Spores: None.

MACROSCOPIC APPEARANCE

Most species produce large colonies. Many colonies appear opaque and translucent.

METABOLIC PROPERTIES

Facultatively anaerobic. Chemoorganotrophic, having both a respiratory and fermentative type metabolism. Glucose and other carbohydrates are catabolized with the production of acid and usually gas. Most species (except Salmonella choleraesuis , subsp. typhi ) are aerogenic.

KEY BIOCHEMICAL REACTIONS

HABITAT

Occurs in humans, warm and cold blooded animals, foods, and in the environment.

PATHOGENICITY

Pathogenic organisms causing fevers (e.g. Typhoid and Enteric), Septicemia, and Gastroenteritis.

RECOMMENDED MEDIA

For culture: Mannitol Selenite Broth, Selenite Cystine Broth, RV Enrichment Broth, or RV Soy Peptone Broth.
For selective isolation: Brilliant Green Agar, XLD Agar, Rambach Agar, Salmonella Shigella (SS) Agar, Brilliant Green Agar Modified, Hektoen Enteric (HE) Agar, or MLCB Agar.
For maintenance: Peptone Agar for short-term maintenance and Lyophilization for long-term storage.

INCUBATION

Temperature: 37 degrees C.
Time: 16-24 hours, subculture enrichment broths after overnight incubation.
Stressed Salmonellae will require preenrichment or resuscitation in Buffered Peptone Water or Lactose Broth for several hours before enrichment broths are used.
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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