Prevalence of chlamydial infections in male patients with nongonococcal urethritis.

Direct examination of urethral smears made evident the presence of chlamydial infection in 162 (38.1%) of 425 male patients with nongonococcal urethritis. Serum antibodies to the group antigen could be detected by complement fixation and microagglutination reactions only in about 50% of the cases with chlamydial infection. The proportion of chlamydial strains isolated in chick embryos was rather low (14.8%) and the isolation rate appeared to correlate with the abundance of urethral secretion.