Trimethoprim as an additional selective agent in media for the isolation of N. gonorrhoeae.

The incorporation of trimethoprim into existing selective media using either saponin-lysed blood agar or chocolate agar as the base is suggested for the routine isolation of the gonococcus. The principal advantage over other selective media is the inhibition of Proteus mirabilis and other commensal organisms as a consequence of which multiple swabs can be plated out onto a single selective plate irrespective of source, while the recovery rate of the gonococcus from these specimens is increased. The relative merits of both basic media are briefly discussed.