Abiotrophia defectiva

  • General information

    • the following information is not yet verified
      A. defectiva is a fastidious organism that requires a complex medium enriched with L-cysteine or vitamin B6 as well as other unique nutritional requirements that are essential for growth.

      Family: Aerococcaceae
      old synonym: Streptococcus defective

      Natural habitat
      They are members of normal flora of the oral cavity or upper respiratory tract as well as the intestinal tract.

      Clinical significance
      They are formally known as NVS (nutritionally variant streptococci) and they are been frequently found in dental plaque.
      The oral cavity is often the portal of entry. Although it is rare for A. defectiva to cause endocarditis they have a greater morbidity and mortality than endocarditis caused by other streptococci due to its poor response to many antibiotics.

      Cases are rare.

  • Gram stain

    • the following information is not yet verified
      Gram positive cocci, 0.4-0.5 µm, grouped in pairs or chains.

      Varying as typical gram positive streptococci to gram variable, enlarged, pleomorphic coccobacilli, the microscopic morphology of the organisms is dependent on the type of medium.

  • Culture characteristics

    • the following information is not yet verified

      Facultatively anaerobic

      Chocolate agar
      They grow as small alpha-hemolytic colonies, max 0.2 mm in diameter.

      Blood agar no growth

      They grow as non-hemolytic or alpha-hemolytic satellite colonies adjacent to Staphylococcus aureus and Staphylococcus sp

      McConkey no growth

      BBAØ growth

  • Characteristics

  • References

    • James Versalovic et al.(2011) Manual of Clinical Microbiology 10th Edition

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