ID#: 8174
Magnified 100x, this 1977 photograph depicted a Petri dish filled with trypticase soy agar medium, containing 5% defibrinated sheep's blood. A loop of diluted culture of Streptococcus pyogenes was put into the melted agar (50oC) just before the blood was added to the melted agar. 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. The characteristic color changes, including a light colored halo surrounding each colony, indicated that these bacteria were beta-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.