Actinomycetes and Streptomycetes

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Actinomycetes and Streptomycetes

• By Ashley Dvorak
• and Aly Johnston

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Actinomycetes

• High GC Gram-positive bacteria
• Most bacteria found in Phylum Actinobacteria are
  often just called Actinomycetes
• Phylum Actinobacteria, Subclass Actinobacteridae,
  Order Actinomycetales

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rRNA Classification
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Phylogenic Relationships
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Structure/Characteristics

• Mostly aerobic, some anaerobic
• Grow on agar above the surface and below the
  surface
• Often form mycelium (massive branching hyphae)
  with conidia (or conidiospores asexual,
  thin-walled spores)
• Not heat-resistant, but adaptive. Not motile.

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Agar Growth
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Spores
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Cell Walls
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Location/Function

• Located primarily in soil or aquatic
  environments widely distributed
• Can degrade numerous organic compounds or
  mineralize organic materials, produce most of the
  medically useful antibiotics, and some exist as
  pathogens

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Suborder Actinomycineae

• Straight or slightly curved rods, are facultative
  or strict anaerobes, found in mucosal surfaces
  (nose or oral cavity)
• A. israelii, A. bovis (Acinomycosis caused by
  infection, trauma or surgery of the face, teeth,
  throat, and sometimes the heart or abdomen)

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Actinomyces
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Suborder Corynebacterineae

• Corynebacterium
• Mycobacterium
• Nocardia / Rhodococcus

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Corynebacterium
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Mycobacterium
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Nocardia
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Suborder Streptomycineae

• One Family Streptomycetaceae
• Three Genera, most important Streptomyces
• Aerial hyphae divide in a single plane to form
  chains of non-motile conidiospores
• Smooth, spiny, warty

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Streptomyces Spores
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Streptomyces

• All strict aerobes
• Cell wall type I
• 0.5-1.0 µm in diameter, varying lengths
• Predominantly found in soil
• Has many morphological and physiological
  characteristics

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Conidia
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Streptomycetes
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Ecological and Medical Importance

• Mineralization
• Aerobically degrades multiple resistant
  substances
• Synthesis of antibiotics
• mainly non-pathogenic

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S. griseus
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S. scabies