Thayer-Martin agar

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Thayer-Martin agar (or Thayer-Martin medium) is a Mueller-Hinton agar with 5% chocolate sheep blood and antibiotics. It is used for culturing and primarily isolating Neisseria bacteria, including Neisseria gonorrhoeae and Neisseria meningitidis, as the medium inhibits the growth of most other microorganisms. When growing Neisseria meningitidis, one usually starts with a normally sterile body fluid (blood or CSF), so a plain chocolate agar is used.

It usually contains the following combination of antibiotics called VCN inhibitor:

• Vancomycin, which is able to kill all Gram-positive organisms;

• Colistin, which is added to kill all Gram-negative organisms except Neisseria; and

• Nystatin, which can kill all fungi.