GC Chocolate Agar with VCAT

This is one of a number of media available for the selective isolation of Neisseria gonorrhoeae. Based on the medium of Thayer & Martin it includes Corn Starch to absorb toxic metabolites and is buffered to maintain a neutral pH. The medium is enriched with Defibrinated Horse Blood where the blood has been ‘chocolated’ by heating the medium to 60°C and made selective by the inclusion of VCAT (Vancomycin, Colistin, Amphotericin and Trimethoprim). Vancomycin and Colistin inhibit the growth of the majority of contaminating organisms likely to be present. Trimethoprim is included to reduce the spread of Proteus spp and Amphotericin to suppress yeasts. Yeast Extract and Glucose are also added as further enrichment.