Etiology of nongonococcal urethritis.

Chlamydia trachomatis was isolated from the urethra from 48 (42 per cent) of 113 men with non-gonococcal urethritis (NGU), four (7 per cent) of 58 without overt urethritis, and 13 (19 per cent) of 69 with gonorrhea. Postgonococcal urethritis (PGU) developed in 11 of 11 men who had C. trum antibody to C. trachomatisis developed. The immunotype specificity of chlamydial antibody corresponded to the immunotype isolated. Among culture-negative patients. chlamydial antibody prevalence correlated with the number of past sex partners and with previous NGU. Herpesvirus hominis, cytomegalovirus, T-mycoplasma, Mycoplasma hominis, other bacteria, and Trichomonas vaginalis were not implicated in NGU or PGU. Thus, the cause of chlamydia-negative NGU and PGU remains obscure. Endocervical chlamydia were found in sex partners of 15 of 22 NGU patients with and two of 24 without urethral chlamydial infection (p smaller than 0.001). Tetracycline treatment of both sex partners appears advisable.