This image depicts a transmission electron micrograph (TEM) of Gram-negative Neisseria gonorrhoeae bacteria, both single bacteria, and diplococcal, or paired organisms. Of the Neisseria and related species, only N. gonorrhoeae is considered always to be pathogenic i.e., cause disease. N. gonorrhoeae is not considered to be normal flora under any circumstances.
N. gonorrhoeae strains may infect the mucosal surfaces of urogenital sites (cervix, urethra, rectum) and the oro- and nasopharynx (throat), causing symptomatic or asymptomatic infections. Gonococcal infections of the urogenital sites are more frequently symptomatic than asymptomatic; however, asymptomatic infections may occur. Gonococcal infections of the oro- and nasopharynx and the rectum may be asymptomatic more frequently than symptomatic. Some specific strains of N. gonorrhoeae have been associated with asymptomatic infections of urogenital sites; these include strains that require arginine, hypoxanthine, and uracil (AHU) or proline, arginine (citrulline), and uracil (PAU) to grow on chemically defined media on which gonococcal strains are characterized.