Sexually transmitted rectal infections in a cohort of 'men having sex with men'

PURPOSE: We assessed the prevalence and predictors of Chlamydia trachomatis, Neisseriagonorrhoeae and Mycoplasmagenitalium rectal infections in a population of 'men having sex with men' (MSM). METHODOLOGY: From January to November 2017, 165 MSM attending a STI outpatients clinic in Bologna (Italy) and reporting unsafe anal intercourses were enrolled. An ano-rectal swab was collected from each patient: chlamydial and gonococcal infections were diagnosed by a commercial NAAT, whereas an in-house quantitative PCR was used for M. genitalium detection. In addition, 131 urine samples and 84 pharyngeal swabs underwent testing for C. trachomatis and N. gonorrhoeae. A molecular C. trachomatis typing, a serological screening for anti-Chlamydia IgG and IgA, as well as the assessment of HIV, HCV and syphilis infections, were performed. RESULTS/KEY FINDINGS. The prevalence of C. trachomatis, N. gonorrhoeae and M. genitalium rectal infections was 27.2, 25.4 and 4.8 %, respectively. Globally, 63.1 % of cases were asymptomatic and up to 80 % of chlamydial and gonococcal infections would have been missed if the rectal site had not been tested. All the patients with rectal M. genitalium carriage were asymptomatic and characterized by low bacterial loads (<2500 DNA copies/reaction). Lymphogranuloma venereum (LGV) prevalence was 12.1 % with a considerable proportion of asymptomatic infections (35 %). The presence of symptoms, age >30, HIV-positivity and elevated levels of anti-Chlamydia antibodies were the most significant predictors of LGV. CONCLUSIONS: Sexually transmitted rectal infections are frequent and often asymptomatic among MSM. LGV prevalence is high in our country and there is increasing evidence of symptomless cases.