The frequency of co-infection with Neisseria gonorrhoeae and Chlamydia trachomatis in men and women in eastern Sydney.

The frequency of simultaneous infection with Neisseria gonorrhoeae and Chlamydia trachomatis in men and women in Eastern Sydney was examined prospectively over a 21 month period in patients from whom appropriate specimens were obtained. In men gonococcal disease (113 cases) and chlamydial infections (124 cases) occurred in approximately equal frequencies, but there were only 4 instances (3.5%) where C. trachomatis was detected at the same time as N. gonorrhoeae. Demographic data and phenotypic profiles of the gonococci isolated suggested that much of the gonorrhea occurred in homosexual men who are generally considered to have a low incidence of chlamydial disease. Gonococcal disease (34 cases) was far less common than chlamydial infection (112 cases) in women, but co-infection with chlamydia was noted in 6 (17.6%) of the cases of gonorrhea (p < 0.01). The current recommendation for the routine addition of tetracyclines to gonococcal treatment regimens for men requires revision.