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Group B Strep Prevention

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Laboratory Personnel, Slide 1

Close Up View of GBS Colony

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Close up GBS Colony
This is a close-up picture of a group B Streptococcus (GBS) growing on a 5% sheep blood agar plate. The red background is the blood agar plate and the gray circular dots are colonies of GBS growing on the agar. The colonies of GBS are gray to whitish-gray surrounded by a weak zone of hemolysis of the red blood cells in the culture medium. Hemolysis is one of the traits that is used to help identify the bacteria. Hemolysis is the destruction of the red blood cells suspended in the agar medium. Before performing the tests in the following photos, a gram strain and catalase test should be performed. GBS are gram-positive cocci in chains and catalase negative.

Page Last Modified: April 20, 2008
Content Last Reviewed: April 20, 2008
Content Source: National Center for Immunization and Respiratory Diseases
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