Genus Ewingella
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacteriales, Family Enterobacteriaceae, Genus Ewingella,
Ewingella americana - type species of the genus, Grimont 1984.
Gram negative, 0.6-0.7 x 1-1.8 μm, straight cells. Motile by means of 3 to 10 peritrichous
flagella.
S-type, non-pigmented colonies. Facultatively anaerobic. Optimum growth temperature
26 ºC. Some strains grow faster and are more active biochemically at 25 ºC than 36 ºC.
Media: Nutrient agar or nutrient broth, Trypticase Soy Agar ± 5% sheep blood.
Widely distributed in nature. Isolated from soil, water (also from catfish & mollusks), mushrooms and from human clinical specimens
(rarely). Blood samples contamination reported. Resistant to penicillin and cephalothin.
Ewingella americana is an infrequent human opportunistic pathogen. May cause nosocomial infections (bacteremia, peritonitis,
conjunctivitis, urinary tract infections).
Is a pathogen of the cultivated mushroom
Agaricus bisporus.
  1. J. G.Holt et al., 1994. Begey’s manual of Determinative Bacteriology, 9th-edition, Williams & Wilkins.
  2. Don J. Brenner and J.J. Farmer III, 2001. Family I. Enterobacteriaceae. In:  Bergey’s Manual of Systematic Bacteriology, Second
    edition,Vol two, part B, George M. Garrity (Editor-in-Chief), pp 587-897.
  3. Hoffman PC, Arnow PM, Goldmann DA, Parrott PL, Stamm WE, McGowan JE Jr. False-positive blood cultures. Association with
    nonsterile blood collection tubes. JAMA. 1976 Nov 1;236(18):2073–2075
  4. Grimont P.A.D., Farmer III J.J., Grimont F., Asbury M.A., Brenner D.J. and Deval C.: Ewingella americana gen. nov., sp. nov., a
    new  enterobacteriaceae isolated from clinical specimens. Ann. Microbiol., 1983, 134A, 39-52.
Positive results for catalase, methyl red, Voges–Proskauer, citrate utilization, ONPG,
nitrate reduction to nitrite, acid production from: D-glucose (without gas), D-mannitol,
salicin, trehalose, D-arabitol, D-mannose & D-galactose.

Negtive results for indole production, H
2S production (TSI), urea hydrolysis, lipase
(corn oil), phenylalanine deaminase, lysine decarboxylase, arginine dihydrolase, ornithine decarboxylase, gelatin hydrolysis (22 °C),
growth in KCN, malonate utilization, acetate utilization, DN-ase, acid production from: sucrose, dulcitol, adonitol, myo-inositol, D-
sorbitol, L-arabinose, raffinose, maltose, D-xylose, cellobiose, alpha-methyl-D-glucoside, erythritol, melibiose & mucate.
(c) Costin Stoica
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