Gonorrhea bacteria. Colored transmission electron micrograph (TEM) of a section through two Neisseria gonorrhea bacteria, the cause of the sexually transmitted disease gonorrhea. They are Gram negative spherical bacteria that are often found in pairs (diplococci), as here. Hair-like fimbriae (yellow) are present on the cell surface. They infect the genital mucous membranes of both sexes, causing pain on urination and a discharge of pus from the vagina or penis. Some cases pass unnoticed, while in others complications may develop leading to sterility. Treatment is with antibiotics. Negatively stained. Magnification: x20,000 at 6x7 cm size.