25 plus species including:



Gram Stain: Negative with a tendency to resist discoloration.
Morphology: "Kidney bean" or "coffee bean" shaped cocci. Occurring singly, but more often in pairs with adjacent sides flattened. One species ( Neisseria elongata ) is an exception and consists of short rods 0.5 micrometers in width and is often arranged as diplobacilli or in short chains. Division of the coccal species is in two planes at right angles to each other sometimes results in tetrad formations.
Size: 0.6-1.0 micrometers in diameter.
Motility: Non-motile.
Capsules: Capsules and fimbriae (pili) may be present.
Spores: None.
Other: Some species are nutritionally fastidious and hemolytic.


Pigmentation of species ranges from white to gray-brown and the texture typically appears smooth, translucent, butyrous to wrinkled, dry, and adherent. Colonies appear small overall. Some species produce a greenish-yellow carotenoid.


Aerobic. Chemoorganotrophic. Some species are nutritionally fastidious, hemolytic, and saccharolytic.



Occurs on mucous membranes of humans and other animals.


Only Neisseria gonorrhoeae and Neisseria meningitidis are specific pathogens causing epidemic and acute meningitis, gonorrhea, and pelvic inflammatory disease in man. The other Neisseria species isolated from humans have been responsible for disease, but it is generally considered that these species are opportunists and rarely cause infection.


For culture: GC Agar Base with Laked Horse Blood or Chocolate Agar.
For selective isolation: Thayer-Martin Medium, FB Broth, or Martin Lewis with Lincomycin.
For maintenance: Chocolate Agar for short-term maintenance. CTA or TSB with 20% Glycerol for storage at -70 degrees C. Lyophilization in a rich broth (Tryptic Soy Broth (TSB), containing 6% Lactose, with storage at 4 degrees C.) is required for long-term preservation.


Temperature: 35-37 degrees C. (with 5-10 % CO 2 and 70% humidity.)
Time: 24-48 hours.
Atmosphere: Aerobic or facultatively anaerobic.


1. Holt, J.G., et al. 1994. Bergey's Manual of Determinative Bacteriology , 9th ed. Williams & Wilkins, Baltimore, MD.

2. Holt, J.G., et al. 1986. Bergey's Manual of Systemic Bacteriology , Vol. I & II. Williams & Wilkins, Baltimore, MD.

3. The Oxoid Vade-Mecum of Microbiology . 1993. Unipath Ltd., Basingstoke, UK.

4. Murray, P.R., et al. 1995. Manual of Clinical Microbiology , 6th ed. American Society for Microbiology, Washington, D.C.

5. Internet: /Bacterial Database Search, February, 1998.

6. Hensyl, B.R., et al. 1990. Stedman's Medical Dictionary , 25th ed. Williams & Wilkins, Baltimore, MD.

7. Koneman, et al. 1997. Color Atlas and Textbook of Diagnostic Microbiology , 5th ed. Lippincott, Philadelphia, PA.