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Aggregatibacter actinomycetemcomitans
A) "rough" colony morphology of a clinical isolateB) "smooth" colony morphology of a spontaneous variant



Dr David Figurski
http://www.intechopen.com/books/genetic-manipulation-of-dna-and-protein-examples-from-current-research/targeted-mutagenesis-in-the-study-of-the-tight-adherence-tad-locus-of-aggregatibacter-actinomycetemc

YOUTUBE-periodontitis


Bone loss from aggressive periodontitis that led to an exposed furcation on an upper molar.




From wikipedia, the free encyclopedia


Farmer at the dentist



Johann Liss 1616

Aggregatibacter actinomycetemcomitans

  • General information


    • Taxonomy
      Family: Pasteurellaceae
      Genus: Aggregatibacter actinomycetemcomitans
      Formerly: Actinobacillus

      HACEK
      The HACEK organisms are a group of fastidious Gram-negative bacteria that are an unusual cause of infective endocarditis, which is an inflammation of the heart due to bacterial infection.
      HACEK is an abbreviation of the initials of the genera of this group of bacteria:
      Haemophilus aphrophilus (Aggregatibacter aphrophilus)
      Aggregatibacter actinomycetemcomitans       (previously Actinobacillus)
      Cardiobacterium hominis
      Eikenella corrodens
      Kingella kingae      .
      The HACEK organisms are a normal part of the human microbiota, living in the oral-pharyngeal region.

      The bacteria were originally grouped because they were thought to be a significant cause of infective endocarditis, but recent research has shown that they are rare and only responsible for 1.4–3.0% of all cases of this disease.

      Natural habitat
      Part of the normal flora of the mouth and pharynx

      Clinical significance
      It is one of the bacteria that might be implicated indestructive periodontal disease.

      It is an oral commensal often found in association with localized aggressive periodontitis, a severe infection of the periodontium.

      It is also associated with non-oral infections, such as abscesses (abdominal, brain, facial, hand, mediastinal and thyroid) and from cases of actinomycosis, endocarditis, meningitis, pneumonia, septicemia and vertebral osteomyelitis.

  • Gram stain

    • Gram negative coccobacillary rods,

      0.3-0.5 x 0.6-1.4 µm,

      They may occur singly, in pairs or in small (big) clumps and show the tendency to bipolar staining.

      This gives an appearance of a "Morse code" of dots and dashes.

      Cells have a microcapsule.

  • Culture characteristics

    • Facultative anaerobic

      5% CO2 improves the growth

      BA: colonies are small, 0.5-3 mm, no hemolysis, they adhere to the agar and are described as starlike or “crossed cigars”.

      Colonies may sometimes have a rough surface and they become mucoid and non-adherent after repeated subculture.

      Broth: when grown in broth bacteria form granules at the bottom and up the sides of the tube (“tiny colonies”), while subsequent cultures become less adherent and exhibit uniform turbidity.

      McConkey: no growth

      BBAØ: growth

  • Characteristics

  • References

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