The Classification and Identification
of Bacteria of Medical Importance

Medically, the most important of the Gram-negative cocci belong to the genus Neisseria. Neisseria meningitidis is an important cause of bacterial meningitis, and Neisseria gonorrhoeae causes gonorrhoea. Members of the genus Neisseria are most often seen in pairs, and are hence sometimes referred to as diplococci. They are very vulnerable to drying, and can only be cultivated in an atmosphere where the concentration of carbon dioxide is greater than that found in air. In the laboratory, carbon dioxide incubators are used that maintain a moist environment with a carbon dioxide concentration of 5-10%.