Edwardsiella tarda
Pathogenicity
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
References
Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacterales, Family Hafniaceae, Genus Edwardsiella, Edwardsiella
tarda
Ewing & McWhorter 1965 - type species of the genus.

Old synonyms: "Paracolobactrum anguillimortiferum" Hoshina 1962,
Edwardsiella anguillimortifera (Hoshina 1962) Sakazaki and
Tamura 1975.

Grimont et al. (1980) described a new biogroup designated
E. tarda biogroup 1,
only biochemically differentiated from
E. tarda (see table below).
Gram-negative, straight bacilli, 1.0 x 2.0-3.0 μm, usually motile by peritrichous flagella
(nonmotile strains may occur). No capsule production.
Growth occurs on usual media, producing small colonies (0.5-1.0 mm in diameter)
after 24 h incubation. Optimum temperature, 37 ºC. Facultatively anaerobic.
Isolated from water, aquatic animals and reptiles and found in the intestinal tract of
snakes and seals. They are occasionally isolated from the urine, blood, and feces of
humans (diarrhoea). Usually resistant to colistin but susceptible to most other
antibiotics, including penicillin.
May cause gastroenteritis and wound infections in humans. Produces the disease
commonly known as fish gangrene, emphysematous putrefactive disease of catfish
or red disease of eels. Produce hemorrhagic ulcers on the body and fins. Bacteria
has a broad host range and causes diseases in freshwater and marine fish, reptiles,
birds and mammals.
Virulence factors: adhesion and invasion of epithelial cells, anti-phagocyte-mediated
killing, production of haemolysin and other toxins.
  1. 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.
  2. J. G. Holt et al., 1994. Facultatively Anaerobic Gram-Negative Rods. Subgroup 1. Family Enterobacteriaceae. In: Begey’s Manual of
    Determinative Bacteriology, 9th-edition, Williams & Wilkins, pp175-189.
  3. Farmer et al.: Proposal to conserve the specific epithet tarda over the specific epithet anguillimortiferum in the name of the
    organism presently know as Edwardsiella tarda: Request for an Opinion. Int. J. Syst. Bacteriol., 1976, 26, 293-294.
  4. De Vos et al.: Judicial Commission of the International Committee on Systematics of Prokaryotes Xth International (IUMS)
    Congress of Bacteriology and Applied Microbiology. Minutes of the meetings, 28, 29 and 31 July and 1 August 2002, Paris, France.
    Int. J. Syst. Evol. Microbiol., 2005, 55, 525-532.
  5. Adeolu M, Alnajar S, Naushad S, S Gupta R. Genome-based phylogeny and taxonomy of the 'Enterobacteriales': proposal for
    Enterobacterales ord. nov. divided into the families Enterobacteriaceae, Erwiniaceae fam. nov., Pectobacteriaceae fam. nov.,
    Yersiniaceae fam. nov., Hafniaceae fam. nov., Morganellaceae fam. nov., and Budviciaceae fam. nov. Int J Syst Evol Microbiol
    2016; 66:5575-5599.
Positive results for catalase, lysine decarboxylase, nitrate reduction, ornithine decarboxylase, acid production from: maltose,
mannose and glucose (usually with gas production).

Negative results for arginine dihydrolase, citrate utilization (Simmons), DN-ase, esculin hydrolysis, gelatinase, beta-galactosidase,
beta-glucuronidase, lipase (Tween 80), malonate utilization, oxidase, L-pyrrolidonyl aminopeptidase, phenylalanine
deaminase,growth in KCN medium, urease (Christensen), Voges-Proskauer, acid production from: adonitol, D-arabitol,
alpha-methyl-D-glucoside, D-cellobiose, dulcitol, inositol, lactose, melibiose, raffinose, L-rhamnose, D-sorbitol and D-xylose.

E. piscicida can only be differentiated from E. tarda by degradation of alpha-methyl-D-glucoside, citric acid and L-proline.
(c) Costin Stoica
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R E G N U M
PROKARYOTAE
Legend:  + positive 90-100%, - negative 90-100%, [+] positive 75-89%, [-] negative 75-89%, d positive 25-74% of strains
 
Hydrogen
sulfide (TSI)
Methyl red
Indole
production
L-Arabinose
fermentation
D-Mannitol
fermentation
Sucrose
fermentation
Trehalose
fermentation
E. tarda / E. piscicida
+
+
+
-
-
-
-
E. tarda biogroup 1
-
+
+
+
+
+
-
E. hoshinae
+
+
d
[-]
+
+
+
E. ictaluri
+
-
-
-
-
-
-
Differential characters between Edwardsiella species:
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