Neisseria  

Neisseria gonorrhoea cells                    Neisseria colonies                        Oxidase-positive reaction of Neisseria

What you should know:

Neisseria is a Gram-negative diplococcus responsible for such serious diseases as gonorrhea and meningitis. Neisserias are obligate aerobes, oxidase-positive, and fastidious. Many can survive inside of host white blood cells, and infections are often identified by finding Gram-negative diplococci in a stain.

Classification: 

Domain Bacteria

    Phylum Proteobacteria

        Class β -Proteobacteria

Bergey's Manual Volume 2: The Proteobacteria