e-Medical Note:

NEISSERIA
Organisms of the genus Neisseria include:

• N. meningitidis - an important cause of meningitis, bacteremia, and other serious infections in both children and adults; 

• N. gonorrhoeae - a major cause of sexually transmitted diseases, including urethritis, cervicitis, proctitis, pharyngitis, salpingitis, epididymitis, and bacteremia/arthritis; 

• And numerous saprophytic Neisseria sp that commonly inhabit the oropharynx, vagina or colon but rarely cause human disease.

Neisseria organisms can be identified by their characteristic colonial morphology, by Gram stain (small gram-negative cocci, often in chains or pairs), and by their positive oxidase reactions. N. meningitidis and N. gonorrhoeae can be distinguished from one another and from saprophytic strains on the basis of sugar usage patterns or by reactions with specific antibodies; many meningococci can be typed with specific anticapsule antibodies, and almost all gonococci react with one or more of a set of monoclonal antibodies directed against porin protein. Neisseria grow well on solid media containing blood or serum and thrive in a reduced O2 atmosphere with 5 to 10% CO2 at 35 to 37° C (95 to 98.6° F). Chocolate agar incubated in a candle jar provides a suitable environment and, supplemented with certain antibiotics, allows growth of most meningococci and gonococci but few nonpathogenic Neisseria.Each of the medically important Neisseria sp is principally responsible for infections of a particular site - Gonorrheal and meningococcal infections.