ID#: 8180
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), just before the blood was added to the agar, a loop of diluted culture was put into the melted agar (50oC). The melted agar with blood was allowed to solidify and then incubated at 35oC for 24 hours in a normal atmosphere. The culture grew subsurface bacterial colonies, one of which was seen here, surrounded by a characteristic hazy, faded, and indistinct region (arrow), in which only some of the red blood cells (RBCs) were destroyed, or hemolyzed, in the agar, indicating that these bacteria were 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.