Pathogenicity
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
References
Phylum Pseudomonadota (Proteobacteria), Class Gammaproteobacteria, Order Enterobacterales, Family Hafniaceae, Genus
Edwardsiella, Edwardsiella piscicida Abayneh et al. 2013.
Gram-negative rods.
Colonies on blood agar after 24 h of incubation at 30 ºC are pin-point, circular, slightly
convex, smooth and glistening with slight beta-haemolysis visible only under the
colony. Optimum temperature for growth is 28-30 ºC. Growth can occur at 25 and 37
ºC but not at 12 or 42 ºC. Growth occurs at 1-5% NaCl but not at 6% or above.
Facultatively anaerobic.
Isolated from diseased fish.
Pathogenic for zebra fish.
- T. Abayneh, D.J. Colquhoun, H. Sorum. Edwardsiella piscicida sp. nov., a novel species pathogenic to fish. J. Appl. Microbiol., 114,
644-654.
- 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.
- 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, malonate utilization, 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), oxidase, L-pyrrolidonyl aminopeptidase, phenylalanine deaminase,growth in KCN medium,
urease (Christensen), Voges-Proskauer, acid production from: amygdalin, adonitol, D-arabitol, alpha-methyl-D-glucoside,
D-cellobiose, dulcitol, inositol, lactose, melibiose, raffinose, L-rhamnose, D-sorbitol and D-xylose.
Variable resultsfor degradation of Tween 80, L-fucose, D-galactose, maltose, D-mannose, bromosuccinic acid,
glucoronamide,L-asparagine, L-aspartic acid, L-glutamic acid, glycyl-L-glutamic acid, glycyl-L-aspartic acid, L-serine, uridine,
glycerol and D,L-alpha-glycerol phosphate.
E. piscicida can only be differentiated from E. tarda by degradation of alpha-methyl-D-glucoside, citric acid and L-proline.

(c) Costin Stoica
Legend: + positive 90-100%, - negative 90-100%, [+] positive 75-89%, [-] negative 75-89%, d positive 25-74% of strains
Differential characters between Edwardsiella species: