gonorrhea (gŏnərēˈə) [key], common infectious disease caused by a bacterium ( Neisseria gonorrhoeae ), involving chiefly the mucous membranes of the genitourinary tract. It may occasionally spread to membranes in other parts of the body, especially those of the joints and the eyes. Since the principal mode of transmission is sexual contact, gonorrhea is classified as a sexually transmitted disease. Gonorrheal conjunctivitis was once a prominent cause of blindness in the newborn, the infection being transmitted during delivery. Routine use of silver nitrate solution in the eyes of every infant at birth has largely overcome this problem.
The usual site of infection in women is the cervix. From there it can spread to the uterus and fallopian tubes and cause pelvic inflammatory disease, ectopic pregnancy, or infertility. Other complications, in both sexes, include infection of the joints, heart valves, and brain. Women are often asymptomatic, but may have a vaginal discharge or burning sensation on urination; men may have a discharge from the penis and pain on urination. Examination of the discharge reveals the presence of the bacteria. In most cases, the disease can be cured by adequate treatment with a cephalosporin antibiotic such as cefixime or ceftriaxone. Failure of treatment is usually due to resistant strains (see drug resistance); gonorrhea is now resistant to many antibiotics formerly used to cure it. Prior infection does not confer resistance and reinfection is common.