Genus Xenorhabdus
Taxonomy
Morphology
Growth conditions
Biochemical characters
Ecology
Pathogenicity
References
Proteobacteria => Gammaproteobacteria => Enterobacteriales => Enterobacteriaceae => Xenorhabdus =>
Xenorhabdus beddingii Akhurst 1986, (basonym: X. nematophila subsp. beddingii)
Xenorhabdus bovienii Akhurst 1983, (basonym: X. nematophila subsp. bovienii)
Xenorhabdus budapestensis Lengyel et al. 2005 *
Xenorhabdus ehlersii Lengyel et al. 2005 *
Xenorhabdus innexi Lengyel et al. 2005 *
Xenorhabdus japonica Nishimura et al. 1995 ** (name japonicus has been corrected by Euzeby and Boemare 2000)
Xenorhabdus luminescens Thomas and Poinar 1979, transferred to Photorhabdus luminescens by Boemare 1993 ***
Xenorhabdus nematophila - type species of the genus, Poinar and Thomas 1965, (name nematophilus  has been corrected by
Euzeby and Boemare 2000), (previously Achromobacter nematophilus)
Xenorhabdus poinarii (Akhurst 1983) Akhurst and Boemare 1993
Xenorhabdus szentirmaii Lengyel et al. 2005 *  

* Note: X. budapestensis, X. ehlersii, X. innexi and X. szentirmaii appear on VALIDATION LIST N° 104 but  <<The inclusion of a name on this list is not to
be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms,
or the organisms may be transferred to another genus, thus necessitating the creation of a  new combination.>> VALIDATION LIST N° 104 cited.
(Validation of publication of new names and new combinations previously effectively  published outside the IJSEM. Int. J. Syst. Evol. Microbiol., 2005,
55, 1395-1397)
** Xenorhabdus japonica strains could not be found in ATCC culture collections (webmaster note).
*** Although the genus Photorhabdus has been proposed, many of the details concerning the phylogeny and taxonomy of the genera  Xenorhabdus and
Photorhabdus have not yet been settled.
Gram negative rods. Motile. Polimorph colonies. X. luminescens produces a faint glow.
Facultatively anaerobic, optimum growth temperature 28°C. Grow on media: Nutrient
Agar or Nutrient Broth, Trypticase Soy Agar ± 5% sheep blood.
Isolated from nematodes in the genera Heterorhabditis and Steinernema.
Xenorhabdus lives in these nematodes stomachs during their non-feeding infective
stage.
Symbiotic bacteria of entomopathogenic nematodes. Together, Xenorhabdus and their nematode host infect and kill insects that are
used during their reproductive cycles.
Toxicity for insects is caused by a series of antimicrobial end products that are excreted by the symbiont during the multiplication of
the nematodes in the insects hosts.
Few reports of  Xenorhabdus luminescens isolates from human wounds.
Some strains may have antibacterial or antifungal activity.
  1. Bergey’s Manual of Determinative Bacteriology, 9th ed., 1994;
  2. Bleakley B. & Nealson K.H.: Characterization of primary and secondary forms of Xenorhabdus luminescens strain Hm, 1988,
    FEMS Microbiol. Ecol. 53: 241-250.
  3. Akhurst R.J. &  Boemare N.E.: A numerical taxonomic study of the genus Xenorhabdus (Enterobacteriaceae) and proposed
    elevation of the subspecies of X. nematophilus to species. J. Gen. Microbiol., 1988, 134, 1835-1845.
  4. Lengyel K., Lang E., Fodor A., Szallas E., Schumann P. & Stackebrandt E.: Description of four novel species of Xenorhabdus,
    family Enterobacteriaceae: Xenorhabdus budapestensis sp. nov., Xenorhabdus ehlersii sp. nov., Xenorhabdus innexi sp. nov.,
    and Xenorhabdus szentirmaii sp. nov. Syst. Appl. Microbiol., 2005, 28, 115-122.
  5. Nishimura Y., Hagiwara A., Suzuki T. & Yamanaka S.: Xenorhabdus japonicus sp. nov. associated with the nematode
    Steinernema kushidai. World J. Microbiol. Biotechnol., 1994, 10, 207-210.
  6. Thomas G.M. & Poinar Jr. G.O.: Xenorhabdus gen. nov., a genus of entomopathogenic nematophilic bacteria of the family
    Enterobacteriaceae. International Journal of Systematic Bacteriology, 1979, 29, 352-360.
  7. Poinar Jr. G.O. and Thomas G.M.: A new bacterium, Achromobacter nematophilus sp. nov. (Achromobacteriaceae:
    Eubacteriales) associated with a nematode. International Bulletin of Bacteriological Nomenclature and Taxonomy, 1965, 15,
    249-252.
  8. Akhurst R.J. & Boemare N.E.: A numerical taxonomic study of the genus Xenorhabdus (Enterobacteriaceae) and proposed
    elevation of the subspecies of X. nematophilus to species. J. Gen. Micr., 1988, 134, 1835-1845.
  9. Boemare N.E., Akhurst R.J., Mourant R.G.: DNA relatedness between Xenorhabdus spp. (Enterobacteriaceae), symbiotic
    bacteria of entomopathogenic nematodes, and a proposal to transfer Xenorhabdus luminescens to a new genus,
    Photorhabdus gen. nov,  1993, International Journal of Systematic Bacteriology. 43:(2) 249-255.
See table at the end. The suggested mode X. luminescens produces light is that it
uses the luciferase pathway as a terminal oxidase allowing it to continue aerobic
metabolism when oxygen is low.

 

Pigment

Catalase

Oxidase

Lactose

ONPG

Arginine dihydrolase

Lysine decarboxylase

Xenorhabdus beddingii

+

-

-

X

X

-

-

Xenorhabdus bovienii

+

-

-

X

X

X

X

Xenorhabdus (Photorhabdus) luminescens

+

+

-

-

-

-

-

Xenorhabdus nematophila

=

-

-

-

-

-

-

Xenorhabdus poinarii

+

-

-

X

X

X

X

 

Ornithine decarboxylase

Indole production

Citrate utilization

Hydrogen sulfide

Urea hydrolysis

Voges-Proskauer

Phenilalanine

Motility

Gelatinase

Growth on KCN media

-

-

-

-

-

-

-

+

+

+

X

=

X

X

-

X

-

+

X

X

-

=

=

-

[-]

-

-

+

=

-

-

=

-

-

-

-

-

+

[+]

-

X

-

X

X

-

X

-

+

X

X

 

Malonate

Glucose

Gas from glucose

D-Mannitol

Inositol

D-Sorbitol

L-Rhamnose

Sucrose (Sacharose)

Melibiose

L-Arabinose

-

X

X

X

X

X

X

X

X

X

X

+

-

X

X

X

X

X

X

X

-

[+]

-

-

-

-

-

-

-

-

-

[+]

-

-

-

-

-

-

-

-

X

X

X

X

X

X

X

X

X

X

 

Nitrate reduction

Cellobiose

Dulcitol

Glycerol

Maltose

D-Mannose

Alfa-Methyl-D-Glucoside

Raffinose

Salicin

Trehalose

-

X

-

=

+

+

-

X

[+]

+

=

X

X

-

X

X

X

X

-

X

-

-

-

-

[-]

+

-

-

-

-

[-]

-

-

-

-

[+]

-

-

-

-

X

X

X

-

X

X

X

X

-

X

 

D-Xylose

Mucate

Tartrate (Jordans)

Esculin hydrolysis

Acetate utilization

Deoxyribonuclease

Lipase

Mehyl red

D-Adonitol

X

X

X

+

X

+

-

-

X

X

X

X

-

X

X

X

X

X

-

-

=

-

-

-

-

-

-

-

-

=

-

-

[-]

-

-

-

X

X

X

-

X

X

X

X

X
X.  budapestensis, X. ehlersii, X. innexi and X. szentirmaii are novel species on the basis of 16S rRNA gene sequences and riboprint patterns and they are
not included in this table.
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