Chlamydia and Gonorrhea Infections in Genital and Extragenital Samples Among Men and Women

For people who have anal and/or oral sex, many programs recommend genital and extragenital (defined here as anorectal and oropharyngeal) screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) to identify all potential sites of infection.

We assessed genital and extragenital CT and NG prevalence among people reporting extragenital sexual exposure.

Among 343 gay and bisexual men who reported sex with men (GBMSM), 42 (12.2%) had CT with positivity of 3.5%, 9.3%, and 1.8% in the genital, anal, and oral samples, respectively. In this same group, 55 (16.0%) had NG with positivity of 5.2%, 8.5%, and 7.6% in the genital, anal, and oral samples, respectively. If only genital screening had been performed, 71.4% of CT infections and 67.3% of NG infections in GBMSM would have gone undetected. Among 96 men who only have sex with women (MSW), 10 (10.4%) had chlamydial infection-all detected in genital samples with no extragenital infections detected. Nine gonococcal infections (9.4%) were detected in MSW, with positivity of 6.3%, 2.1%, and 3.1% in the genital, anal, and oral samples, respectively. If only genital testing had been performed, no CT infections would have been missed among MSW; however, 33.3% of NG infections would have been missed. Among 329 cisgender women, 35 (10.6%) had CT with positivity of 7.9%, 6.1%, and 1.8% in the genital, anal, and oral samples, respectively. In the same group, 17 (5.2%) had NG with positivity of 4.0%, 2.1%, and 2.4% in the genital, anal, and oral samples, respectively. Among these women, 25.7% and 23.5% of CT and NG infections, respectively, would not have been detected.

The increased case finding when including extragenital testing for GBMSM and women was confirmed in this analysis. However, the benefit-cost ratio and the clinical or public health value of extragenital screening in these different populations require further study.