ID#: 16897
The blood agar medium in this Petri dish culture plate was inoculated with a Streptococcus sp. bacterium, which after having gone through a period of incubation, grew subsurface bacterial colonies, one of which is seen here, surrounded by what is known as wide zone alpha (WZa) hemolytic color changes. Characteristics of WZa reactivity are described as, "the area immediately adjacent to the colony has some red blood cells (RBCs), but an area outside of that may be completely, or nearly completely, cleared of RBCs. Therefore, there are no reactive zones where complete RBC hemolysis has occurred, as in the case of beta-hemolytic reactions, hence the Wide Zone alpha terminology.”
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Content Provider(s): CDC/ Dr. Max D. Moody
Creation Date: 1970
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.