ABSTRACT
Background Mycoplasma genitalium is increasingly seen as an emerging sexually transmitted pathogen, and has been likened to Chlamydia trachomatis, but its natural history is poorly understood. The objectives of this systematic review were to determine M. genitalium incidence, persistence, concordance between sexual partners, and the risk of pelvic inflammatory disease (PID).
Methods We searched Medline, EMBASE, LILACS, IndMed and African Index Medicus from 1 January 1981 until 17 March 2018. Two independent researchers screened studies for inclusion and extracted data. We examined results in forest plots, assessed heterogeneity and conducted meta-analysis where appropriate. Risk of bias was assessed for all studies.
Results We screened 4634 records and included 17 studies; five (4100 women) reported on incidence, five (636 women) on persistence, 10 (1346 women and men) on concordance and three (5139 women) on PID. Incidence in women in two very highly developed countries was 1.07 per 100 person-years (95% CI, 0.61 to 1.53, I2 0%). Median persistence of M. genitalium was estimated from one to three months in four studies but 15 months in one study. In ten studies measuring M. genitalium infection status in couples, 39-50% of male or female sexual partners of infected participants also had M. genitalium detected. In prospective studies, the incidence of PID was higher in women with M. genitalium than those without (RR 1.68, 95% CI 0.59 to 2.77, I2 0%, 2 studies).
Discussion Based on findings from this and our linked review of prevalence, concordant M. genitalium might be less common than for C. trachomatis and the age distributions of the infections differ. The synthesised data about prevalence, incidence and persistence of M. genitalium infection are inconsistent. Taken together with evidence about antimicrobial resistance in the two infections, M. genitalium is not the new chlamydia.
Registration Numbers PROSPERO: CRD42015020420, CRD42015020405
KEY MESSAGES
There are calls for widespread screening for Mycoplasma genitalium, but the natural history of this emerging sexually transmitted pathogen is poorly understood.
M. genitalium incidence was 1.07 (95% confidence intervals, CI 0.61 to 1.53) per 100-person years in women in highly developed countries, 39-50% of infected individuals had a heterosexual partner with M. genitalium and the risk ratio for pelvic inflammatory disease was 1.68 (95% CI 0.59 to 2.77).
The duration of untreated M. genitalium infection is probably longer than persistent detection of M. genitalium, as measured in most cohort studies, in which inadvertent treatment cannot be ruled out.
The results of this systematic review and other evidence sources show important differences in the epidemiology and dynamics of M. genitalium and Chlamydia trachomatis infection.