Gonorrhoeae: a sexually transmitted disease. Color enhanced TEM of negatively stained lysed Neisseria gonorrhoeae. Old culture showing diplococcal feature and flagella. Neisseria are gram-negative and usually occur in pairs with flattened sides but may occur single or in irregular groups. N. gonorrhoeae is the causative agent of gonorrhea, a specific, contagious, catarrhal inflammation of the nervous system likewise requires the programmed death of swarms of neurons, prior to completion of the fetal brain. Magnification: x2,100 at 35mm.