Differences between Neisseria gonorrhoeae and Neisseria meningitides

Neisseria gonorrhoeae and Neisseria meningitides are Gram negative diplococci (kidney bean-shaped) with flattened sides.  They are characteristically found inside polymorphonuclear leucocytes. They are non-sporing, non-motile and oxidase positive.

They have exacting growth requirements and do not grow on ordinary media. Growth occurs on media enriched with blood or serum like Chocolate Agar, Thayer Martin Agar and Modified New York City Medium.

Some of the notable differences between them are:

Characteristics Neisseria gonorrhoeae (Gonococci) Neisseria meningitides (Meningococci)
Capsule No polysaccharide capsule Yes (has a prominent polysaccharide capsule; and is divided in to 13 serologic groups on the basis of capsular antigens)
Pili Yes (One of the most important virulence factor; nonpiliated strains are avirulent) Yes
Portal of Entry Genital Respiratory
  • Male: urethritis, proctitis
  • Female: endocervicitis, PID (contiguous spread), arthritis, proctitis
  • Infants: ophthalmia  neonatorum
  • Otitis media
  • Sinusitis
  • Bronchitis and bronchopneumonia in elderly patients with COPD
 Meningitis and meningococcemia
Glucose Fermentation Yes Yes
Maltose Fermentation* No Yes
Β-Lactamase Production Common Rare (Penicillin G is the treatment of choice for meningococcal infection)
Vaccine available No Yes (Conjugate vaccine and unconjugate vaccine is available)

*  The differentiation between Neisseria meningitidis and Neisseria gonorrhoeae is made on the basis of sugar fermentation: meningococi ferment maltose  (MM), whereas gonococci do not. 

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