The Natural History of Mycoplasma genitalium at the Pharynx and Rectum in a Cohort of Men who have Sex with Men: Prevalence, Incidence, Duration and Symptomatology.

Abstract

Little is known about Mycoplasma genitalium's (MG) natural history in the throat and the rectum. Methods: Men who have sex with men (MSM) enrolled in a longitudinal cohort study on the natural history of extragenital gonorrhea and chlamydia. Men self-collected pharyngeal and rectal specimens weekly and completed electronic symptom and sexual behavior diaries for 48 weeks. Prevalent infections were detected on the first week of testing; incident infections were ≥2 consecutive weeks of positive specimens after a negative test. We calculated duration using Kaplan-Meier analysis. Of 140 enrolled MSM, 112 participated and 108 submitted samples on week one. Ten (9.3%) had prevalent rectal MG; there were fifteen incident rectal MG infections (incidence 19.8 per 100 person years (py), 95% CI:11.5-34.1 per 100 py). Rectal MG had a median duration of 42 weeks (95% CI: 7.3 weeks - undefined); most infections (60%) were entirely asymptomatic. Four (3.7%) participants had prevalent pharyngeal infections. Fourteen incident pharyngeal infections arose (incidence 17.5 per 100 person years, 95% CI: 9.9-30.8 per 100 py). Pharyngeal MG had a median duration of 12 weeks (95% CI: 6.3 weeks - undefined); symptoms were rare (6%). Rectal and pharyngeal MG was common in this cohort. Half of the rectal MG infections persisted for nearly a year; many remained positive on week 48 suggesting persistence beyond one year. Pharyngeal infection persisted three months. The absence of symptoms or other morbidity in most infections suggests testing for MG at these sites would have uncertain individual benefit.