Background
Screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in men who have sex with men (MSM) is risk-based. Despite high frequencies of oral and receptive anal intercourse (RAI) among women, extragenital screening is not recommended.
Methods
Women (n=175) and MSM (n=224) primarily recruited from a sexually transmitted infections clinic reporting a lifetime history of RAI completed a structured questionnaire and clinician collected swab samples from the rectum, pharynx, vagina (women) and urine (men). CT and GC were detected using two commercial nucleic acid amplified tests (Aptima Combo 2, Hologic, Inc., Bedford, MA; Xpert CT/NG, Cepheid Innovation, Sunnyvale, CA).
Results
The median age of the population was 26 years, 62% were Caucasian, and 88% were enrolled from a Sexually Transmitted Diseases clinic. Men were more likely than women to have GC (22.8% vs. 3.4%) and CT (21.9% vs. 12.6%). In men vs. women, GC was detected in 16.5% vs. 2.3% of pharyngeal swabs, 11.6% vs. 2.3% of rectal swabs and 5.4% vs. 2.9% of urine samples or vaginal swabs. CT was detected in 2.2% vs. 1.7% of pharyngeal swabs, 17.4% vs. 11.4% of rectal swabs, and 4.5% vs 10.3% for urogenital sites in men vs. women. Overall 79.6% of CT and 76.5% of GC in men and 18.2% of CT and 16.7% of GC in women were detected only in the pharynx or rectum.
Conclusion
Reliance on urogenital screening alone misses the majority of GC and CT in men and more than 15% of infections in women reporting RAI.