New York City agar

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The NYC (

Gonococci.[1]

The growth of Neisseria gonorrhoeae colonies on New York City medium agar

Composition

The agar base is composed of:[1]

Ingredients Grams per litre
Proteose peptone 15
Corn starch 1
Glucose 5
Sodium chloride 5
Dipotassium hydrogen phosphate 4
Potassium dihydrogen phosphate 1
Agar 20

Final pH ( at 25°C) 7.4±0.2

Background and principles

NYC Agar Base was originally developed by Fauer, Weisburd and Wilson

antibiotics.[1][2] This medium is superior to other media generally employed for the isolation of Neisseria species.[1][4][5] The transparent nature of the medium helps in studying the colonial types.[6]

Proteose peptone, horse plasma,

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

The growth of Neisseria meningitidis colonies on New York City Medium Agar

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:[10]

  1. Roll swab directly on the medium in a large “Z” to provide adequate exposure of swab to the medium for transfer of organisms.
  2. Cross-streak the “Z” pattern with a sterile wire loop, preferably in the clinic. If not done previously, cross-streaking should be done in the laboratory.
  3. Place the culture as soon as possible in an aerobic environment enriched with carbon dioxide.
  4. Incubate at 35 ± 2 °C and examine after overnight incubation and again after approximately 48 hours.
  5. N. gonorrhoeae
    should be made within 18–24 hours. If shipped after incubation, colonies should be subcultured before performing biochemical identification tests in order to ensure that adequate viability is achieved.

Expected results

Typical colonial morphology is as follows:[7]

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.

References

  1. ^ a b c d e Fauer, Weisburd, Wilson and May, 1973, Health Lab. Sci., 10: 44.
  2. ^ a b Fauer, Weisburd and Wilson, 1973, Health Lab. Sci., 10: 55.
  3. ^ Fauer Y. C., Weisburd M. H. and Wilson M. E., 1973, Health Lab Sci., 10(2) 61.
  4. ^ Granato, Schneible-Smith and Weiner, 1981, J. Clin. Microbiol.13:963.
  5. ^ Griffin P. J. and Reider S. V., 1957, J. Biol. Med., 29, 613
  6. ^ MacFaddin J. F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1, Williams and Wilkins, Baltimore
  7. ^ a b Knapp and Koumans. 1999. In Murray, Baron, Pfaller, Tenover and Yolken (ed.), Manual of clinical microbiology, 7th ed. American Society for Microbiology, Washington, D.C
  8. ^ . Simmons N. A., 1970, J. Clin. Pathol., 23, 757.
  9. ^ Lawton and Koch, 1982, J. Clin. Microbiol., 20: 905
  10. ^ Center for Disease Control. 1975. Criteria and techniques for the diagnosis of gonorrhea, USPHS, Atlanta, Ga.
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