Assessment of a selective medium for the isolation of Neisseria gonorrhoeae

Specimens of urethral pus from 312 men with gonorrhoea were diluted and inoculated on to non-selective and selective media, the latter containing vancomycin, colistin, nystatin, and trimethoprim. Although three (1%) isolates of Neisseria gonorrhoeae were inhibited by trimethoprim 4 mg/1 and 10 by vancomycin 2 mg/1, only two failed to grow on a selective medium from large inocula but eight strains sensitive to vancomycin failed to grow on a selective medium from a light inoculum. These few failures do not appear to negate the value of the selective medium.