(P91) Genital and Extragenital Chlamydia and Gonorrhea infections among Men and Women from a Clinical trial Evaluating Test Performance in Extragenital Samples

Background

Many programs recommend 3-site (genital, anal, and throat) screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) to identify all potential sites of infection. We assessed positivity among a subset of participants enrolled in an evaluation of the performance of extra-genital samples (from the ExGen study) using 4 assays.

Methods

We included 768 cis-gender participants who had genital standard-of-care testing in addition to anal and throat results. Anal and throat specimens were considered positive for CT or NG if they were positive in at least 3 of the 4 assays. Transgender persons enrolled were excluded due to small numbers (n=6).

Results

For 42 CT-infected men who reported sex with other men, infections were detected in 9/343 (2.6%) genital-only, 24/343 (7.0%) anal-only, 1/343 (0.3%) throat-only, 3/343 (0.87%) genital+anal, and 5/343 (1.5%) anal+throat, respectively. For men who reported sex only with women, all CT infections [10/96 (10.4%)] were found only in the genital sample. For 35 CT-infected women, infections were detected in 12/329 (3.7%) genital-only, 6/329 (1.8%) anal-only, 2/329 (0.6%) throat-only, 11/329 (3.3%) genital+anal, 1/329 (0.3%) genital+throat, 1/329 (0.3%) anal+throat, and 2/329 (0.6%) at all 3 sites, respectively.

For 55 NG-infected men who reported sex with other men, infections were detected in 9/343 (2.6%) genital-only, 17/343 (5.0%) anal-only, 12/343 (3.5%) throat-only, 3/343 (0.9%) genital+anal, 5 (1.5%) genital+throat, 8 (2.33%) anal+throat, and 1 (0.3%) at all 3 sites, respectively. For the 9 NG-infected men who reported sex only with women, NG infections were detected in 5/96 (5.2%) genital-only, 2/96 (2.1%) throat-only, 1/96 (1.0%) genital+anal, and 1/96 (1.0%) anal+throat, respectively. Among 17 NG-infected women, NG was detected in 5/329 (1.5%) genital-only, 2/329 (0.6%) anal-only, 2/329 (0.6%) throat-only, 2/329 (0.6%) genital+anal, 3/329 (0.9%) genital+throat, and 3/329 (0.9%) at all 3 sites, respectively.

Conclusions

The importance of 3-site testing for men who report sex with men was confirmed in this analysis. Three-site screening also identified small numbers of infections in women and men reporting sex only with women that would not have been identified by genital screening alone. Studies are needed to elucidate whether expanded screening is warranted.