Gonorrhea and chlamydia prevalence in different anatomical sites among men who have sex with men: a cross-sectional study in Guangzhou, China.

Background: A high rectal and oropharyngeal sexually transmitted infection (STI) burden has been reported among men who have sex with men (MSM) in many regions, but little data exists on rectal and oropharyngeal STIs among MSM in China. The purpose of this study was to determine the prevalence of gonorrhea and chlamydia at different anatomic sites among MSM in Guangzhou, China.
Methods: We recruited a cross-sectional sample of MSM in one Chinese city and collected detailed information about socio-demographic characteristics and sexual behaviors. Men had urine, rectal, and pharyngeal swab samples tested for gonorrhea and chlamydia using nucleic acid amplification tests (NAAT). Univariate and multivariate logistic regressions were used to evaluate factors associated with gonorrhea and chlamydia. Among men without any STI symptoms, we also examined the prevalence of gonorrhea and chlamydia by anatomical site.
Results: We enrolled 463 men between January 2015 and March 2017. A total of 58/463 (12.5%) of men had gonorrhea and 84/463 (18.1%) had chlamydia. MSM with gonorrhea were more likely to have been recruited from the STI clinic (OR 3.41, 95% CI 1.94-5.99), living with HIV (OR 2.41, 95% CI 1.18-4.92), diagnosed had STI co-infection (OR 2.55, 95% CI 1.39-4.69). MSM with chlamydia were more likely to be students (OR 1.8, 95% CI 0.99-3.39). Most gonorrhea (34/58, 59%) and chlamydia (64/84, 76%) infections were not associated with STI symptoms.
Conclusion: Asymptomatic gonorrhea and chlamydia infection were common in this sample of Chinese MSM. Further research is necessary to determine optimal STI screening programs.