A carbohydrate fermentation plate medium is described for rapid and reliable confirmation of Neisseria gonorrhoeae, N. meningitidis, and other Neisseria species. The medium is based on a modification of NYC (U.S. Patent 3,846,241) medium, originally designed for the isolation of pathogenic Neisseria (3). A total of 715 clinical isolates were tested for their carbohydrate fermentation reactions on the medium, in parallel with cystine-Trypticase agar medium. In 82% of the strains tested, results were in agreement on both media and 18% gave conflicting results. The NYC modification provides rapid and accurate fermentation patterns for use in routine confirmation procedures for Neisseria species.

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NYC medium, primarily designed for isolation of pathogenic Neisseria , also readily supports the growth of large-colony mycoplasmas and T-mycoplasmas. When compared with A-3 agar medium and PPLO agar in clinical field trials, NYC medium performed equally as well as these mycoplasma-specific media in providing recovery of Mycoplasma species from female genital specimens. The transparent, highly-selective NYC medium permits direct, microscopic observation and presumptive identification of mycoplasmas, as well as Neisseria gonorrhoeae , without interference from contaminating saprophytes. As a single medium it can therefore be doubly useful in the diagnosis of gonorrhea and in the recognition of active or asymptomatic mycoplasma infections. Used in gonorrhea screening programs, the medium can be valuable in establishing the frequency of association of mycoplasmas with urogenital tract infection.

Mycoplasma hominis and T-colony mycoplasmas were observed growing among or developing within gonococcal colonies on primary isolation plates streaked for detection of N. gonorrhoeae in urogenital specimens. The frequency of such association of mycoplasmas with gonococci was as high as 84% among patients screened for gonorrhea in several Social Hygiene Clinics of the City of New York, Department of Health, Bureau of Venereal Disease Control. The individual morphology of both mycoplasmal and gonococcal colonies was characteristic when viewed through the light microscope, and their associated growth was maintained throughout numerous serial transfers on agar culture media. Electron microscopy of such interrelated colonies revealed nipple-like projections on the gonococcal cell walls, to which the mycoplasmas appeared to be firmly attached. These morphologic observations are presented and discussed.

The biological environment-CO2 chamber containing New York City (NYC) medium was evaluated in a clinical field trial in comparison with Transgrow and NYC medium in plates for the recovery of Neisseria gonorrhoeae and with NYC medium for urogenital mycoplasmas. The results of the study indicated that the biological environment chamber-CO2 culturing system with NYC medium is an effective method for the handling, transport, and culture of N. gonorrhoeae, large-colony mycoplasmas, and T-mycoplasmas if the delay in transport and incubation does not exceed 24 h.