ERWINIA

30 plus species including:

SPECIES

Erwinia amylovora
Erwinia ananas
Erwinia cacticida
Erwinia carotovora
Erwinia chrysanthemi
Erwinia cypripedii
Erwinia herbicola (now Pantoea agglomerans )
Erwinia mallotivora
Erwinia nigrifluens
Erwinia persicinus
Erwinia psidii
Erwinia quercina
Erwinia rhapontici
Erwinia rubrifaciens
Erwinia salicis
Erwinia stewartii (now Pantoea agglomerans )
Erwinia tracheiphila
Erwinia uredovora (now Pantoea agglomerans)

MICROSCOPIC APPEARANCE

Gram Stains: Gram-negative.
Morphology: Straight rods.
Size: 0.5-1.0 micrometer by 1.0-3.0 micrometers.
Motility: Erwinia spp. are motile by peritrichous flagella (except E. stewartii ).
Capsules: None.
Spores: None.
Other: They occur singly or in pairs and sometimes in short chains.

MACROSCOPIC APPEARANCE

Colony morphology for these organisms vary depending upon the type of media on which they are cultivated. In general, the colonies appear as white, smooth colonies. They may be domed, shining, mucoid-type colonies with radial striations or may appear smooth with entire edges. Craters may form around the colonies on some media. Pigments may be produced by some species; ranging from cream, pale yellow to light pink.

METABOLIC PROPERTIES

Acid (little/no gas) from sugars.

KEY BIOCHEMICAL REACTIONS

HABITAT

Associated with plants as pathogens, saprophytes or part of epiphytic flora.

PATHOGENICITY

Very rarely isolated from humans. Erwinia species cause plant diseases which include blights, cankers, die back, leaf spots, wilts, discoloration of plant tissues, and sot rots variously described as stalk rot, crown rot, stem rot, or fruit collapse. Erwinia uredovora is a parasite of rust fungi and multiples in the plant tissue infected by the rust organism. Strains of E. herbicola are common in the epiphytic microflora of plants; instances have been reported in which E. herbicola has produced symptoms on plants, sometimes possibly in association with other phytopathogenic bacteria. (2)

RECOMMENDED MEDIA

For culture: Nutrient Agar, Tryptic Soy Agar, Blood Agar 5%, Glucose Nutrient Agar.
For selective isolation: MacConkey Agar. (Selective culture media is not usually necessary for isolation of this organism from plant material.) (2)
For maintenance: Nutrient Agar, Tryptic Soy Agar, Blood Agar 5%. For long-term storage at - 70 degrees C., TSB with 15 % Glycerol or Skim Milk Media is recommended.

INCUBATION

Temperature: 25-30 degrees C.
Time: 24-48 hours.
Atmosphere: Aerobic (facultative anaerobic).

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, 1986.

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.


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