Thayer–Martin agar

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Thayer–Martin agar (or Thayer–Martin medium, or VPN agar) 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. Thayer–Martin agar was initially developed in 1964, with an improved formulation published in 1966.^[1]^[2]^[3]

Components

It usually contains the following combination of antibiotics, which make up the VPN acronym:

Vancomycin, which is able to kill most Gram-positive organisms, although some Gram-positive organisms such as Lactobacillus and Pediococcus are intrinsically resistant
Polymyxin, also known as colistin, which is added to kill most Gram-negative organisms except Neisseria, although some other Gram-negative organisms such as Legionella are also resistant
Nystatin, which can kill most fungi
Trimethoprim inhibits swarming of Proteus spp^[4]

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. ^{[citation needed]}

References

^ "THAYER-MARTIN Agar (Base)".
^ THAYER JD, MARTIN JE (January 1964). "A Selective Medium for the Cultivation of N. Gonorrhoeae and N. Meningitidis". Public Health Rep. 79 (1): 49–57. doi:10.2307/4592051. JSTOR 4592051. PMC 1915495. PMID 14105729.
^ Thayer JD, Martin JE (June 1966). "Improved medium selective for cultivation of N. gonorrhoeae and N. meningitidis". Public Health Rep. 81 (6): 559–62. doi:10.2307/4592771. JSTOR 4592771. PMC 1919807. PMID 4957043.
^ Tankeshwar, Acharya (2016-06-13). "Modified Thayer-Martin Agar: Composition, preparation, uses and colony characteristics". Learn Microbiology Online. Retrieved 2020-10-28.

Growth media / agar plates

Selective media

Gram positive

Actinomycetota	Mycobacterium tuberculosis Löwenstein–Jensen medium Middlebrook 7H9 Broth Middlebrook 7H10 Agar Middlebrook 7H11 Agar Mycoplasma pneumoniae Eaton's agar
Bacillota	Corynebacterium diphtheriae Hoyle's agar Enterococcus Bile esculin agar Lactobacillus Lee's Agar MRS agar Lactococcus M17 agar Listeria Fraser broth PALCAM Staphylococcus Mannitol salt agar Baird-Parker agar Vogel–Johnson agar

Gram negative

Alphaproteobacteria	Brucella Brucella agar Farrell's medium
Betaproteobacteria	Neisseria Thayer–Martin agar New York City agar
Gammaproteobacteria	Aggregatibacter actinomycetemcomitans Tryptic soy-serum-bacitracin-vancomycin Bordetella Bordet–Gengou agar Enterobacteriaceae VRBD agar Haemophilus influenzae/Legionella pneumophila Buffered charcoal yeast extract agar Pseudomonas aeruginosa Cetrimide agar Salmonella XLT agar DCA agar Salmonella/Shigella XLD agar

Differential media

Fungal media

Nonselective media

Other/ungrouped media

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