Further studies with a selective medium for cultivating Neisseria gonorrhoeae.

A culture medium that is selective for the gonococcus and the meningococcus has been described recently (Thayer and Martin, 1964). The medium with Polymyxin and Ristocetin added permits isolation of the gonococcus from sites highly contaminated with other bacteria. Overgrowth of gonococcal colonies by the commensal bacterial flora present in rectal, vaginal, and cervical specimens is almost completely prevented. In addition, the nonpathogenic Neisseria such as N. sicca, N. catarrhalis, N. flava, and others fail to grow or are greatly inhibited. Among the many Gram-negative bacteria prevented from growing is the oxidase positive variant of Mima polymorpha. Although Mima polymorpha is seldom encountered, it may be mistakenly identified as N. gonorrhoeae if sugar fermentation tests are not carried out. This report presents the results obtained by using the Thayer-Martin (TM) selective medium (Wende, Forshner, and Knox, 1964), a conventional chocolate agar medium, and the delayed fluorescent antibody (FA) procedure (Deacon, Peacock, Freeman, Harris, and Bunch, 1960) on specimens from vaginal, cervical, and rectal sites.