Haloferax alexandrinus

Bacteria
General | Carbohydrate O/F | Substrate utilisation | Enzymes | Metabolites | Antibiotics

Overview

  • Haloferax alexandrinus is a Gram-negative, non-spore-forming, strictly aerobic, non-motile, pleiomorph rod-shaped bacterium. It has been detected in at least 1 gut microbiome compilation study or metastudy. The DNA G+C content is 59.3%. Haloferax alexandrinus is likely to be transient and not a long-term gut coloniser. (Asker2002)



  • This organism has been recovered from extreme salt conditions, Egypt. The risk classification (www.baua.de) for this organism is 1, i.e., low risk of infection and spread. Pathogenicity status unknown, or very unlikely to be pathogenic. Likely to be transient and not a long-term gut commensal.
    • QUIRKS
  • Lyses in water, so unlikely to be a coloniser of the gut. Requires high levels of Mg2+.
    • GENERAL CHARACTERISTICS (Asker2002);
    Character Response
  • Substrates hydrolysed or digested:
  • gelatin;
  • 🧂
  • Salt tolerance:
  • tolerates 10-25% salt; Grows optimally with 25% salt.
  • pH
  • Acidity tolerance:
  • tolerates pH 5.5; tolerates pH 7.5; Grows optimally at pH 7.2.
  • 🌡
  • Temperature tolerance:
  • grows at 20℃; grows at 55℃;
  • H+
  • Acid from carbohydrates usually produced:
  • L-arabinose; fructose; glucose; rhamnose; ribose; xylose; maltose; sucrose; glycerol; N-Ac glucosamine;
  • ⥅
  • Substrates assimilated or utilised:
  • glucose; glycerol; succinate; Casamino acids;
  • Active enzymes:
  • catalase; β-galactosidase; oxidase; tryptophan deaminase;
    • SPECIAL FEATURES (Asker2002);
    Character Response
  • ✓
  • Metabolites produced:
  • H₂S; indole;
  • ✗
  • VP test:
  • not active
  • ✓
  • Nitrate:
  • reduced
  • ✓
  • Nitrite:
  • reduced
  • ✓
  • Thiosulfate:
  • reduced
    • RESPONSE TO ANTIBIOTICS (Asker2002);
    Class Active Resistant
  • Macrolides:
  • erythromycin; josamycin;
  • Tetracyclines:
  • tetracycline;
  • Aminoglycosides:
  • neomycin;
  • Polypep/ketides:
  • bacitracin;
  • rifampicin;
  • Heterocycles:
  • chloramphenicol;
  • Miscellaneous antibiotics:
  • novobiocin;

    • Details

    GENERAL
    Lineage Physiology General Growth Tolerances Hydrol./digest./degr.
    Phylum:  Euryarchaeota Class:  Halobacteria Order:  Haloferacales Family:  Haloferacaceae Genus:  Haloferax Gram stain:  neg O2 Relation.:  strictly aerobic Spore:  No spore Motility:  Sessile Morphology:  Pleiomorph rod
    Health:  Unknown
    Source:  extreme salt conditions, Egypt
    DNA G+C(%):  59.3
    Lower T(℃):  20(+)
    High T(℃):  55(+)
    NaCl >6%:  10-25(+)
    Opt. pH:  7.2
    pH 4.2-5.9:  5.5(+)
    pH 6.0-8.0:  7.5(+)
    		Urea:  neg Gelatin:  + Starch:  neg Casein:  neg Tween:  80(+)
    CARBOHYDRATE ACID FORMATION
    Monosaccharide O/F Oligosaccharide O/F Polysaccharide O/F Polyol O/F Other O/F
    L-Arabinose:  + Fructose:  + Galactose:  neg Glucose:  + Mannose:  neg Rhamnose:  + Ribose:  + Xylose:  + Lactose:  neg Maltose:  + Sucrose:  + Glycerol:  + NAc-α-GA:  +
    SUBSTRATE ASSIMILATION & UTILISATION
    Monosaccharide util/assim Oligosaccharide util/assim Other carboh. util/assim Amino acid util/assim Organic acid util/assim
    Galactose:  neg Glucose:  + Mannose:  neg Lactose:  neg Glycerol:  + Starch:  neg Citrate:  neg Succinate:  +
    ENZYME ACTIVITY
    Enzymes: General Enzymes: Carbohydrate Enzymes: Protein Enzymes: Arylamidases Enzymes: Esters/fats
    Oxidase:  + Catalase:  + Urease:  neg β-Galactosidase:  + ArgDH:  neg LysDC:  neg OrnDC:  neg TrpAA:  +
    METABOLITES - PRODUCTION & USE
    Fuel Usable Metabolites Metabolites Released Special Products Compounds Produced

    		H2S:  + Indole:  +
    ANTIBIOTICS ℞
    Penicillins & Penems (μg/mL) Cephalosporins (μg/mL) Aminoglycosides (μg/mL) Macrolides (μg/mL) Quinolones (μg/mL)
    neomycin:  R(30; disc)
    erythromycin:  R(15; disc)
    josamycin:  R(180; disc)
    Tetracyclines (μg/mL) Vancomycin Class (μg/mL) Polypep/ketides (μg/mL) Heterocycles (μg/mL) Other (μg/mL)
    tetracycline:  R(30; disc)
    bacitracin:  S(30; disc)
    rifampicin:  R(100; disc)
    chloramphenicol:  R(30; disc)
    novobiocin:  S(30; disc)

    References

    SPECIFIC REFERENCES FOR HALOFERAX ALEXANDRINUS
  • Asker2002 - Haloferax alexandrinus sp. nov., an extremely halophilic canthaxanthin-producing archaeon from a solar saltern in Alexandria (Egypt).
  • ...............................
    • GUT MICROBIOME COMPILATIONS AND METASTUDIES FOR HALOFERAX ALEXANDRINUS
  • Lagier2016 - Culture of previously uncultured members of the human gut microbiota by culturomics.
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    • Added: February 09, 2022