The Natural History of Mycoplasma genitalium in the Pharynx and Rectum in a Cohort of Men Who Have Sex With Men: Prevalence, Incidence, Duration, and Symptoms.

BACKGROUND

Little is known about the natural history of Mycoplasma genitalium (MG) in the throat and the rectum.

METHODS

Men who have sex with men were 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 defined as ≥2 consecutive weeks of positive specimens after a negative test result. We calculated duration using Kaplan-Meier analysis.

RESULTS

Of 140 enrolled men who have sex with men, 112 participated and 108 submitted samples on week 1. Ten (9.3%) had prevalent rectal MG, and there were 15 incident rectal MG infections (incidence, 19.8/100 person-years [95% confidence interval (CI), 11.5-34.1/100 person-years). Rectal MG had a median duration of 42 weeks (95% CI, 7.3 weeks to undefined); most infections (60%) were entirely asymptomatic. Four participants (3.7%) had prevalent pharyngeal infections, and there were 14 incident pharyngeal infections (incidence. 17.5/100 person-years [95% CI, 9.9-30.8/100 person-years]). Pharyngeal MG had a median duration of 12 weeks (95% CI, 6.3 weeks to undefined); symptoms were rare (6%).

CONCLUSIONS

Rectal and pharyngeal MG was common in this cohort. Half of the rectal MG infections persisted for nearly a year; many remained positive at week 48, suggesting persistence beyond 1 year. Pharyngeal infection persisted for 3 months. The absence of symptoms or other morbidity in most infections suggests that testing for MG at these sites would have uncertain individual benefit.