Thayer-Martin agar

Thayer-Martin agar
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 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 was characterized in 1964 and 1966.[1][2][3]


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

  • Vancomycin, which is able to kill most Gram-positive organisms, although some Gram-positive organisms such as Lactobacillus and Pediococcus are intrinsically resistant;
  • Colistin, which is added to kill most Gram-negative organisms except Neisseria, although some other Gram-negative organisms such as Legionella are also resistant;
  • SXT, which inhibits Gram-negative organisms, especially swarming proteus

Clinical Implications

A negative culture on Thayer-Martin in a patient exhibiting symptoms of pelvic inflammatory disease most likely indicates an infection with Chlamydia trachomatis


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Thayer-Martin agar — chocolate agar enriched with vitamins and other supplements, to which is added antibiotic inhibitors (vancomycin, colistin, and nystatin), used for the transport and primary culture of Neisseria gonorrhoeae and N. meningitidis. Called also TM a …   Medical dictionary

  • Agar plate — Infobox Laboratory equipment name = Agar plate caption = An agar plate streaked with microorganisms isolated from a deep water sponge. Individual colonies may be seen center right. acronym = other names = uses = Culturing inventor = manufacturer …   Wikipedia

  • agar — A complex polysaccharide (a sulfated galactan) derived from seaweed (various red algae); used as a solidifying agent in culture media; it has the valuable property of melting at 100°C, but not solidifying until 49°C. [Bengalese] bile salt a. an a …   Medical dictionary

  • Thayer — James D. See T. Martin medium, T. Martin agar …   Medical dictionary

  • Chocolate agar — showing Francisella tularensis colonies …   Wikipedia

  • MacConkey agar — with lactose (left) and non lactose (right) fermenters …   Wikipedia

  • Cysteine lactose electrolyte deficient agar — A clear CLED agar plate after cultivation …   Wikipedia

  • DCA agar — A microbiological culture of Salmonella sp. bacteria on DC agar culture medium DCA agar Deoxycholate Citrate Agar is a solid bacteriological growth medium. Uses It is particularly useful for the isolation of organisms that cause bacilliary… …   Wikipedia

  • Cetrimide agar — is a type of agar used for the selective isolation of the gram negative bacteria, Pseudomonas aeruginosa.[1] As the name suggests, it contains cetrimide, which is the selective agent against alternate microbial flora.[2] Cetrimide also enhances… …   Wikipedia

  • Nutrient agar — is a microbiological growth medium commonly used for the routine cultivation of non fastidious bacteria. It is useful because it remains solid even at relatively high temperatures. Also, bacteria grown in nutrient agar grows on the surface, and… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”