🦠microbiology review

Actinomycetes

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Actinomycetes are a group of Gram-positive bacteria known for their filamentous growth and soil-dwelling nature. They are notable for producing numerous antibiotics.

5 Must Know Facts For Your Next Test

  1. Actinomycetes are responsible for the production of over two-thirds of naturally derived antibiotics, including streptomycin and tetracycline.
  2. They exhibit filamentous growth similar to fungi, which makes them unique among bacteria.
  3. These microorganisms play a critical role in decomposing organic matter in soil, contributing to nutrient cycling.
  4. Streptomyces is the most well-known genus within Actinomycetes, widely studied for its antibiotic-producing capabilities.
  5. Actinomycetes can also produce secondary metabolites that have antifungal, antiviral, and anticancer properties.

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