Prevalence of Mycoplasma genitalium and Co-Infections with Chlamydia trachomatis and Neisseria gonorrhoeae Among Japanese Women: A Cross-Sectional Study

Background/Objectives: Mycoplasma genitalium is an emerging cause of sexually transmitted infections (STIs) and is increasingly recognized for its association with cervicitis and pelvic inflammatory disease. However, prevalence data in specific Japanese subpopulations, particularly comparing pregnant and non-pregnant women, remains limited. This study aimed to determine the prevalence of M. genitalium and its co-infection rates with Chlamydia trachomatis and Neisseria gonorrhoeae among Japanese women. Methods: A cross-sectional study was conducted using vaginal swab specimens collected between April 2021 and November 2022 from patients visiting two clinics in Gifu, Japan. The study population comprised 2138 non-pregnant women presenting with urogenital symptoms or sexual contact history, and 236 pregnant women undergoing routine antenatal screening. Detection was performed using real-time polymerase chain reaction assays on the cobas® 8800 system (Roche Diagnostics). Results: Among non-pregnant women, the overall prevalence was 3.8% (82/2138) for M. genitalium, 3.4% (72/2138) for C. trachomatis, and 0.4% (9/2138) for N. gonorrhoeae. Co-infection rates were low; M. genitalium and C. trachomatis co-infection was observed in 0.2% of cases. Among pregnant women, the prevalence was 3.8% (9/236) for both M. genitalium and C. trachomatis, and 0.4% (1/236) for N. gonorrhoeae. No statistically significant differences in prevalence were observed between pregnant and non-pregnant women for any pathogen. Conclusions: The prevalence of M. genitalium in this Japanese cohort was comparable to that of C. trachomatis in both pregnant and non-pregnant women, highlighting its significance as a major STI pathogen. These findings underscore the importance of including M. genitalium in routine STI screening panels for symptomatic women and antenatal care to prevent reproductive health complications. Given the high rates of antimicrobial resistance documented in Japanese M. genitalium strains, specific diagnostic testing is essential to enable targeted, resistance-guided therapy.