Objective: The objective of this study was to explore risk behavior and routes of transmission in men having sex with men (MSM) with newly diagnosed sexually transmitted infections (STIs).
Methods: A questionnaire on clinical diagnosis and manifestation site for acute STIs was completed by physicians participating in a sentinel study. Patients contributed information on sexual risk behavior and the likely route of STI transmission.
Results: Three hundred fifty-six diagnosis forms and 169 matching patient questionnaires could be analyzed. The most frequent diagnosis was syphilis (n = 147; 33% primary syphilis with ulcer localization 71% genital, 22% anorectal, and 8% oral; 67% secondary syphilis), followed by gonorrhea (n = 136; 59% genital, 34% rectal, 7% pharyngeal) and Chlamydia trachomatis infection (n = 51; 48% genital, 48% rectal, 4% pharyngeal). In 12 patients, more than one infection was diagnosed, and 2 or 3 sites were affected in 11 patients. Approximately 60% of infections were acquired by genital–oral and oral–anal practices. Unprotected anal intercourse (UAI) was reported more often by HIV-positive men (mostly receptive) and men with high partner numbers.
Conclusion: High partner numbers, an important role of genital–oral sexual practices for the transmission of STIs, and relatively high frequencies of mostly receptive UAI in HIV-positive men are all contributing to increasing STI incidences among MSM.