New York City agar

The N.Y.C (New York City) medium or GC ("Neisseria gonorrhoeae") medium agar is used for isolating Gonococci.
Composition.
The agar base is composed of:
"Final pH ( at 25°C) 7.4±0.2"
Background and principles.
NYC Agar Base was originally developed by Fauer, Weisburd and Wilson at the New York City Department of Health for selective isolation of pathogenic "Neisseria" species from clinical specimens. It consists of primarily a peptone-corn starch agar-base buffered with phosphates and supplemented with horse plasma, horse haemoglobin, dextrose, yeast autolysate and antibiotics. This medium is superior to other media generally employed for the isolation of "Neisseria" species. The transparent nature of the medium helps in studying the colonial types.
Proteose peptone, horse plasma, haemoglobin provide nutrients for the growth of "N. gonorrhoeae" and "N. meningitidis". Phosphate buffers the medium. The selective supplement added contains the antibiotics vancomycin, colistin, nystatin and trimethoprim, to suppress the accompanying flora. Vancomycin is inhibitory for gram-positive bacteria. Colistin inhibits gram negative bacteria, including "Pseudomonas species", while Proteus is inhibited by trimethoprim. The combination of trimethoprim and colistin acts synergistically against gram-negative bacilli. Starch neutralizes the toxic metabolites produced by "Neisseria". The yeast autolysate supplement fulfils the CO2 requirements needed to enhance "Neisseria" growth. Yeast contains oxaloacetic acid which is metabolized by gonococci to produce sufficient CO2 for growth of capnophilic gonococci. Also, presence of yeast autolysate reduces the lag phase of growth of "Neisseria", thus enhancing both size and number of colonies. The specimen can be directly streaked on the medium to obtain maximum isolation.
Procedure.
Streak the specimen as soon as possible after it is received in the laboratory. If material is being cultured directly from a swab, proceed as follows:
Expected results.
Typical colonial morphology is as follows:
"N. gonorrhoeae" may appear as small (0.5–1.0 mm) grayish white to colorless mucoid colonies.
"N. meningitidis" appears as large colorless to bluish-gray mucoid colonies.
Colonies may be selected for Gram-staining, subculturing or other diagnostic procedures.