Comparison of two culture media types used to grow Neisseria gonorrhoeae bacteria.
Known as overgrowth, note that the non-selective chocolate agar medium on the left, due to its composition, allowed for the growth of organismal colonies other than those of Neisseria gonorrhoeae, while the selective Thayer-Martin medium on the right, containing antimicrobials that inhibit the growth of organisms other than N. gonorrhoeae, shows no overgrowth, but is positive for N. gonorrhoeae bacteria.
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 pathogenic Neisseriabacteria, 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. Thayer-Martin agar was initially developed in 1964, with an improved formulation published in 1966.