GC Agar

GC Agar is used with lysed blood and other supplements for the isolation and cultivation of Neisseria gonorrhoeae and other fastidious organisms. GC Agar is not intended for use in the diagnosis of disease or other conditions in humans.

A nutritious agar base described by Thayer and Martin for the isolation of Neisseria gonorrhoeae. The rich peptone mixture is enhanced by the use of corn starch to absorb toxic metabolites and a buffering system is used to maintain neutral pH. The medium is made selective by the use of various antibiotic cocktails. Thayer and Martin originally recommended the use of vancomycin, colistin and nystatin and the addition of trimethoprim which is useful in preventing the swarming of proteus. More recently the emergence of vancomycin sensitive gonococci has made the selective agents (lincomycin, colistin, amphotericin, trimethoprim (X070 LCAT) the combination of choice. Enrichment of the base is usually by the addition of lysed blood. Alternatively, chocolated blood or hemoglobin powder and Thayer and Martin’s mixture of vitamins, amino acids and coenzymes can be used. GC Growth Supplement (X271) can be added to this medium to aid in the isolation of Neisseria spp.