ObjectivesThis investigation sought to characterise risk factors associated with acquisition of traditional and emerging agents of sexually transmitted infection (STI) in a cohort of young men who have sex with men and transgender women.Methods917 participants provided urine and rectal swab submissions assessed by transcription-mediated amplification (TMA)-based assays for Chlamydia trachomatis and Neisseria gonorrhoeae and by off-label TMA-based Trichomonas vaginalis and Mycoplasma genitalium testing. A subset provided specimens at 6-month and 12-month follow-up visits.ResultsPrevalence of M. genitalium from rectal and urine specimens (21.7% and 8.9%, respectively) exceeded that of C. trachomatis (8.8% and 1.6%) and other STI agents. Black participants yielded higher prevalence of M. genitalium (30.6%) than non-black participants (17.0%; χ²=22.39; p<0.0001). M. genitalium prevalence from rectal specimens was 41.5% in HIV-positive participants vs 16.3% in HIV-negative participants (χ²=57.72; p<0.0001). Participant age, gender identity, condomless insertive anal/vaginal sexual practice and condomless receptive anal sexual practice were not associated with rectal C. trachomatis (p≥0.10), N. gonorrhoeae (p≥0.29), T. vaginalis (p≥0.18) or M. genitalium (p≥0.20) detection. While prevalence of T. vaginalis was calculated at ≤1.0%, baseline rectal and urine screening status was predictive of detection/non-detection at follow-up. A non-reactive M. genitalium baseline rectal or urine screening result was less predictive of non-reactive follow-up versus C. trachomatis, N. gonorrhoeae and T. vaginalis.ConclusionsRectal M. genitalium detection is associated with black race and HIV seropositivity. Baseline M. genitalium infection influences subsequent detection of the organism.