Pseudomonas aeruginosa
Pseudomonas aeruginosa, Gram stain.
Colonies and green, fluorescent, diffusible pigment
Haemolysis on sheep blood agar
Cultural characteristics
Biochemical characters
Phylum Proteobacteria, Class Gammaproteobacteria, Order Pseudomonadales, Family Pseudomonadaceae, Genus Pseudomonas,
Pseudomonas aeruginosa
- type species of the genus, (Schroeter 1872) Migula 1900.
Synonyms: "
Bacterium aeruginosum" Schroeter 1872, "Bacterium aeruginosum" Cohn 1872, "Micrococcus pyocyaneus" Zopf 1884,
Bacillus aeruginosus" Trevisan 1885, "Bacillus pyocyaneus"  Flügge 1886, "Pseudomonas pyocyanea" Migula 1895,
Bacterium pyocyaneum" Lehmann and Neumann 1896, "Pseudomonas polycolor"
Clara 1930.
Gram-negative, 0.5-0.8 x 1.5-3 μm rods, motile by a polar monotrichous flagellum
(exceptions may occur).
Colonies have the tendency  to swarm. Produce diffusible fluorescent pigments
(pyoverdin) and a soluble phenasine pigment “pyocyanin” (blue to red). Frequently
hemolytic on blood agar.  Pyoverdin and pyocyanin of pathogenic strains are capable
to lyse erythrocytes and suspension of purified chicken egg lecitin, contributing to total
hemolytic activity, which is not determined only by phospholipase C produced by
Presents phase variation. 3 colony types may be formed:
  • small, rough colony; the surface is wrinkled with irregular or radiant crests.
  • large, smooth, with flat edges and an elevated appearance (fried egg
  • mucoid appearance, convex, entire edges, smooth shining surface.

Strictly aerobic except with media with nitrate, optimal temperature 30 - 37 ºC, can
grow up to 44 ºC. No growth at 4 ºC. Media: Trypticase Soy Agar  ± 5% sheep blood,
Trypticase Soy Broth, Mueller-Hinton agar, Mac Conkey agar, Drigalski,  Hektoen, SS
Widely distributed in nature. Isolated from soil, water , plants, clinical human & animal
specimens (wounds, burns, respiratory and urinary tract ).
Bacterium is the causative agent of “blue pus” (from where the “pyocyaneus” name
Produces urinary tract infections, respiratory infections, dermatitis, conjunctivitis, otitis,
osteomielitis, systemic infections, nosocomial infections, particularly in organisms
who are immunosuppressed. Individuals with extensive burns, or those who have been subjected to surgical procedures,
catheterization, and treatment with broad-spectrum antibiotics, are particularly vulnerable targets.
Produces two extracellular protein toxins (Exoenzyme S and Exotoxin A), cytotoxin, hemolysins and two extracellular proteases
(elastase & alkaline protease).
Plant pathogen (isolated from tobacco spotted leafs).
  1. Bergey’s Manual of Determinative Bacteriology, 9th ed., 1994.
  2. Migula W.: System der Bakterien, Vol. 2, Gustav Fischer, Jena, 1900.
  3. Schroeter J.: Über einige durch Bacterien gebildete Pigmente. (1872). In: F. Cohn (ed.), Beitrage zur Biologie der Pflanzen, J.U.
    Kern's Verlag, Breslau, 1875, pp. 109-126.
  4. Topley & Wilson’s Microbiology and Microbial Infections, 10 edition, Vol. 2, Bacteriology, Edward Arnold Ltd.
  5. George M. Garrity, Julia A. Bell & Timothy Lilburn: Order IX Pseudomonadales Orla-Jensen 1921 In: Bergey’s Manual of
    Systematic Bacteriology, Second edition,Vol two, part B, George M. Garrity (Editor-in-Chief), 2005, pp. 323-442.
  6. Tratat de microbiologie clinica, D. Buiuc, M. Negut, Ed. Medicala, Bucuresti, 770-771.
  7. Pyzh AE, Nikandrov VN. Contribution of blue-green pigments to hemolytic activity of Pseudomonas aeruginosa cultural fluid. Zh
    Mikrobiol Epidemiol Immunobiol. 2011 Jan-Feb;(1):19-25.
Positive results for nitrates reduction, arginine dihydrolase, oxidase, gelatin hydrolysis,  
lipase, utilization of citrate, acetate, alanine, L-asparagine, L-aspartate, betaine,
caprate, fumarate, beta-hydroxybutyrate, lactate, malate, proline, putresceine, pyruvate,
succinate, adipate, beta-alanine, arginine, spermine, L-tyrosine, anthranilate, benzoate,
butanol, 2.3.butylene glycol, butyrate, caprate, ethanol, propanol, D-fructose, D-glucose,
gluconate, glycerol, glycerate, histamine, L-histidine, p-hydroxybenzoate, isobutanol,
isobutyrate, itaconate, mesaconate, 2-ketogluconate, L-leucine, levulinate, L-lysine,
malonate, mannitol, L-ornithine, propionate, ribose & valerate.

Negative results for lecithinase, indole production, levan formation, utilization of
adonitol, arabinose, benzylamine, cellobiose, ethylene glycol, fucose, inulin,
isopropanol, lactose, maleate, maltose, methanol, poly-beta-hydroxybutyrate, salicin,
starch, L-threonine, citraconate, creatine, D-galactose, glycolate, hippurate, o- & m-
hydroxybenzoate, m-inositol, D-mannose, mucate, naphtalene, nicotinate,
pantothenate, phenol, L-rhamnose, sorbitol, sucrose, tartrate, testosterone, trehalose,
D-tryptophan & D-xylose.

Urease, utilization of citraconate, dodecane, hexadecane, ethanolamine, glycine,
L-isoleucine, L-valine, D-malate, L-phenylalanine, propylene glycol, sarcosine, L-serine
& L-tryptophan are variable.
(c) Costin Stoica
Culture media
Biochemical tests
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Pseudomonas aeruginosa