Colonies are pale violet, very thin, slightly roughened, spreading, irregular, 5-10 mm
in diameter On low nutritive media, colonies are very thin, with rough surfaces and
irregular edges, and spreading to 1 cm or more in diameter; they are of butyrous
consistency and are easily emulsified in water. Sometimes colonies may be
gelatinous. Usually hemolytic. Produce nonspreading colonies on rich media. Growth
in nutrient broth is moderate after 24 h at 25 ºC, with uniform turbidity and a violet ring
at the surface but no pellicle. Optimum growth temperature is 25 ºC. Unable to grow
at 37 ºC (growth limits are 4-30 ºC). Facultative anaerobe. Growth occurs in the
presence of 1% NaCl (rarely in 2% NaCl and not in 4% NaCl).
Cultural characteristics
Biochemical characters
Phylum Proteobacteria, Class Betaproteobacteria, Order Neisseriales, Family Chromobacteriaceae, Genus Iodobacter, Iodobacter
corrig. (Moss et al. 1981) Logan 1989.

Old synonym:
Chromobacterium fluviatile Moss et al. 1981.
Gram-negative, round-ended rods, 0.7 x 3.0-3.5 μm, occurring singly, in pairs, chains,
and rarely as long filaments. Motile by means of a polar flagellum and one or more
lateral flagella.
Isolated from running fresh water in England and Scotland, and from Antarctic lakes.
Sensitive to chloramphenicol, chlortetracycline, furazolidone , kanamycin, nalidixic acid, nitrofurantoin, oxytetracycline and tetracycline;
slightly sensitive to neomycin, streptomycin, and sulfafurazole.
Resistant to ampicillin, cephaloridine, colistin, penicillin G, and vibriostatic agent 0/129.
  1. Logan N. 1989. Numerical Taxonomy of Violet-Pigmented, Gram-Negative Bacteria and Description of Iodobacter fluviatile gen.
    nov., comb. nov. Int J Syst Evol Microbiol 39(4):450-456 doi:10.1099/00207713-39-4-450.
  2. Moss M, Ryall C, Logan N. 1978. The Classification and Characterization of Chromobacteria from a Lowland River Microbiology
    105(1):11-21 doi:10.1099/00221287-105-1-11.
  3. J. P. Euzeby, 1997. Revised Nomenclature of Specific or Subspecific Epithets That Do Not Agree in Gender with Generic Names
    That End in -bacter. Int J Syst Evol Microbiol 47(2):585-585 doi:10.1099/00207713-47-2-585.
  4. Tone Tonjum, 2005. Order IV. Neisseriales ord. nov. In:  Bergey’s Manual of Systematic Bacteriology, Second edition, Vol two, part
    C The Alpha-, Beta-, Delta-, and Epsilonproteobacteria, George M. Garrity (Editor-in-Chief), pp 774-863.
  5. Euzeby (J.P.): List of Bacterial Names with Standing in Nomenclature: a folder available on the Internet. Int. J. Syst. Bacteriol.,
    1997, 47, 590-592. (List of Prokaryotic names with Standing in Nomenclature.
Positive results for catalase, gelatin hydrolysis, nitrate reduction (without gas production), oxidase, phosphatase, acid production
from: fructose, glucose, maltose, mannose, trehalose & N-acetylglucosamine.
Can utilize malate as sole carbon source.

Negative results for arginine hydrolysis, esculin hydrolysis, H
2S production, HCN production, indole production, nitrite reduction, lysine
decarboxylase, ornithine decarboxylase, phenylalanine deamination, starch hydrolysis; urease, Voges-proskauer test, acid production
from: arabinose, cellobiose, galactose, glycogen, inositol, inulin, lactose, mannitol, melezitose,
raffinose, sorbitol, starch, sucrose & xylose.
No utilization of: lactate, proprionate & tartrate.

Variable results for hydrolysis of casein, egg yolk reaction, acid production from: gluconate & glycerol.
Variable utilization of: acetate, citrate, fumarate, glycerate, pyruvate & succinate.
Iodobacter fluviatilis
(c) Costin Stoica
Culture media
Biochemical tests
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