ID#: 8179
Magnified 100x, this 1977 photograph depicted a Petri dish filled with trypticase soy agar medium containing 5% defibrinated sheep's blood. After having been inoculated with alpha-hemolytic, Streptococcus anginosus bacteria, a member of the Gram-positive viridans group of streptococci (VGS), the blood agar plate (BAP) was incubated in a carbon dioxide enriched atmosphere at 35oC for 24-hours. The culture grew these bacterial colonies, which exhibited characteristic color changes, including a hazy, faded, indistinct region surrounding each colony in which only some of the red blood cells (RBCs) were destroyed, or hemolyzed, in the blood agar medium, indicating that these bacteria were indeed alpha-hemolytic in nature.
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Content Provider(s): CDC/ Richard R. Facklam, Ph.D.
Creation Date: 1977
Photo Credit:
CDC Organization
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Copyright Restrictions: None - This image is in the public domain and thus free of any copyright restrictions.