Transmission of Chlamydia trachomatis and Neisseria gonorrhoeae among men with urethritis and their female sex partners.

Transmission of Chlamydia trachomatis and Neisseria gonorrhoeae among infected men and their female sex partners was examined using a design enhancing the likelihood that spread was directed from men to women. Chlamydia culture-negative specimens were examined using DNA amplification tests. Infection rates in women exposed to male sex partners with Chlamydia only were 65% (20/31) and with gonorrhea only were 73% (33/45). Infection of women by either agent was not influenced by the number of sexual exposures to or coinfection in men. There was a 98% (40/41) concordance of N. gonorrhoeae isolates among partners by auxotype and serovar. Chlamydia isolates were serotyped using ELISA and immunofluorescence testing and confirmed by nested polymerase chain reaction: 50% (6/12) of men and 57% (8/14) of women yielded mixed serovars. Sixty-four percent of pairs (9/14) were infected with identical serovars and an additional 28% shared at least one serovar. Multiple serovars of C. trachomatis, but not of N. gonorrhoeae, were common in sex partners and exchanged frequently.

Underdiagnosis of Chlamydia trachomatis infection. Diagnostic limitations in patients with low-level infection.

To determine limitations in commonly used methods for detection of Chlamydia trachomatis, 601 genitourinary specimens from patients in a sexually transmitted disease clinic were examined with quantitative cultures and by 2 different direct antigen tests, immunofluorescence (Micro Trak; Syva Company, Palo Alto, CA) and enzyme immunoassay (Chlamydiazyme; Abbott Laboratories, North Chicago, IL). Genital specimens were held no longer than 5 hours (at 4 degrees C) prior to inoculation for culture; 28% (168/601) were positive. To evaluate the effect of storage on culture efficacy, duplicate specimens were also stored at -70 degrees C and brought out subsequently for culture a second time. Only 32% (8/25) of specimens cultured within 5 hours and having less than 10 inclusions were positive on reculture, compared with 98% (49/50) positive for specimens with greater than or equal to 10 inclusions initially (P less than 0.001). Sensitivities of the two antigen tests were similar and taken together diminished significantly (P less than 0.001) as the number of organisms (inclusion forming units) in corresponding cultures decreased: 82% (51/62) sensitivity in cultures with greater than 100 inclusions; 50% (22/44) with 10-100 inclusions; and only 11% (6/53) with less than 10. Lack of urethral discharge in men with C. trachomatis infection (free of Neisseria gonorrhoeae) was associated with low numbers of inclusions (less than 10) and antigen tests failed in 68% (15/22) of these patients.