ID#: 16561
This image shows a Petri dish culture plate containing Tinsdale medium, inoculated with a throat swab, and which subsequently grew small bacterial colonies that exhibited a dark brown to black coloration, and surrounded by a darkly colored halo. Tinsdale agar is used in the isolation of Corynebacterium diphtheriae bacteria, which produce hydrogen sulfide (H2S) from cysteine, and sodium thiosulfate, that then reacts with the tellurite salt in the agar medium in the form of potassium tellurite (K2TeO3), giving rise to gray-black colonies, each surrounded by a dark brown halo.
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Content Provider(s): CDC
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.