Streptomyces - LabCE.com, Laboratory Continuing Education

How to Subscribe

MLS & MLT Comprehensive CE Package Includes 186 CE courses, most popular	$109	Add to cart
Pick Your Courses Up to 8 CE hours	$55	Add to cart
Individual course	$25	Add to cart

The page below is a sample from the LabCE course Medically Important Aerobic Actinomycetes. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Medically Important Aerobic Actinomycetes (online CE course)

Streptomyces

The Streptomyces genus contains over 600 species. Most are known for the ability to synthesize antibiotics.

S. somaliensis is the most common species isolated from clinical specimens. Clinically, Streptomyces are most often associated with mycetoma (similar to Actinomadura infections).

Table 2. Characteristics of Streptomyces species.

Characteristics	Comments
Appearance on Gram stain	Gram positive, filamentous, extensive branching with chains and spores; does not fragment easily; hyphae are 0.5–2.0 microns in diameter²⁷
Appearance on modified acid-fast stain (MAS)	Not partially acid-fast
Most often associated with clinical disease	Streptomyces sudanensus, Streptomyces somaliensis (most common)
Colonial growth	Discrete waxy, heaped colonies; variable growth to include leathery, granular, powdery, velvety²⁷
Phenotypic characterization²⁷	Casein, tyrosine hydrolysis Lysozyme resistance negative Gelatin hydrolysis positive Urea hydrolysis variable Nitrates are reduced to nitrites Degrades esculin Degrades starch
Temperature of optimal growth	Growth at 25–35°C

27. National Health Service. (2016). UK standards for microbiology investigations: Identification of aerobic actinomycetes. The Royal College of Pathologists. https://www.rcpath.org/static/ce08d742-b58e-4e8d-986c43a75ac367c3/uk-smi-id-10i2-2-identification-of-aerobic-actinomycetes-october-2016-pdf.pdf
Figure 18. CDC/Berd. (1972). Image #2983. This is a slide culture of a Streptomyces sp. bacteria, which had been cultivated on tap water agar. Note the branching filamentous hyphae, abundant aerial mycelia, and long chains of small spores are visible, which is characteristic of all Streptomyces spp. PHIL public domain. https://phil.cdc.gov/Details.aspx?pid=2983
Figure 19. CDC/Ajello. (1967). Image #21826. This image depicted a frontal view of a Petri dish culture plate that had contained an unidentified growth medium, which had been inoculated with a bacterial culture labeled, 45-657-67, of Streptomyces somaliensis organisms, and which subsequently produced these irregularly-shaped, rough bacterial colonies. PHIL public domain. https://phil.cdc.gov/Details.aspx?pid=21826

Figure 18. Streptomyces bacteria prep from a slide culture demonstrating long chains of small spores

Figure 19. Streptomyces growth on agar