Objectives: To determine the prevalence of pharyngeal and rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections among men who have sex with men (MSM) in Germany and describe associations between these infections, sexual practices and other factors to provide an evidence base for screening recommendations.
Methods: We conducted a cross-sectional study in 22 sentinel sites of sexually transmitted infections across Germany. Pharyngeal and rectal swabs were collected and tested for CT and NG with a nucleic acid amplification test (NAAT). Information on HIV status, number of sex partners and sexual practices was collected and linked to NAAT results.
Results: Overall, 2247 MSM were screened for pharyngeal or rectal CT and NG infections; median age was 34 years (range 16-83). Prevalence of CT was 1.5% in pharyngeal and 8.0% in rectal specimens. Prevalence of NG was 5.5% in pharyngeal and 4.6% in rectal specimens. Local symptoms were reported in 5.1% of pharyngeal and 11.9% of rectal infections. Altogether 90.8% of rectal or pharyngeal infections would remain undetected if only symptomatic cases were tested. Rectal infection was significantly more likely in men reporting multiple partners (2-5 partners, OR=1.85; 6-10 partners, OR=2.10; >11 partners, OR=2.95), men diagnosed with HIV (OR=1.60) and men practising receptive anal intercourse without a condom (OR=1.54). Pharyngeal infection was more likely in men reporting multiple partners (6-10 partners, OR=2.88; >11 partners, OR=4.96), and men diagnosed with HIV (OR=1.78).
Conclusions: Pharyngeal and rectal infections in sexually active MSM can remain undetected and thus transmissible if swabbing is not offered routinely. Screening should be offered particularly to MSM diagnosed with HIV and MSM reporting multiple partners.
Keywords: EPIDEMIOLOGY (GENERAL); HIV; INFECTION; SCREENING; SEXUAL HEALTH.