Details - Public Health Image Library(PHIL)

ID#:

8196

Caption:

Magnified 100x, this 1977 photograph depicted a Petri dish filled with heart infusion agar medium containing 5% defibrinated rabbit blood, referred to as a blood agar plate (BAP). A loop of diluted Streptococcus anginosus bacterial culture of was put into the melted agar (50^oC), just before the blood was added to the melted agar. The agar was allowed to solidify, and then incubated at 35^oC for 24-hours in a normal atmosphere. The culture grew subsurface colonies, one of which is seen here, surrounded by what is known as wide zone alpha hemolytic color changes, whereupon, 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 is no reactive zones where complete RBC hemolysis had occurred, as is the case in beta-hemolytic reactions, hence the wide zone alpha terminology.

High Resolution:

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Content Provider(s):

CDC/ Richard R. Facklam, Ph.D.

Creation Date:

1977

Photo Credit:

Links:

Categories:

CDC Organization