Comparison of hemoglobin-free culture media and thayer-martin medium for the primary isolation of Neisseria gonorrhoeae.

Translucent culture media are essential for the determination of gonococcal colony types. In this study two hemoglobin-free, translucent culture media were compared with Thayer-Martin (TM) medium for the primary isolation of Neisseria gonorrhoeae from male urethral specimens. The antibiotic-free translucent medium (GCB) and the translucent medium containing vancomycin, colistin, and nystatin (VCN) were as efficient as TM medium in detecting positive specimens. In fact, VCN medium gave positive results significantly more often than TM medium(P less than 0.05). The amount of growth on positive plates was comparable for all three media. Contaminants were noted most often on GCB medium (P less than 0.0001), and the frequency of contaminants with TM plates exceeded that of VCN plates (P less than 0.0001). The high isolation rate of N. gonorrhoeae with VCN hemoglobin-free culture medium and its lower cost and greater ease of preparation make it a suitable alternative to TM medium for use with male urethral specimens.