The Impact of Introducing Mycoplasma genitalium (MG) Testing for Acute Non-Gonococcal Urethritis (NGU) and MG-Specific Treatment on Persistent NGU Cases

Abstract

Mycoplasma genitalium (MG) is a common cause of non-gonococcal urethritis (NGU), particularly in persistent cases that often result from undetected and not optimally treated infections. In response to rising local prevalence of macrolide resistance, the Public Health-Seattle & King County (PHSKC) Sexual Health Clinic (SHC) began MG testing at first NGU presentation in 2018 and treating MG infections with doxycycline followed by moxifloxacin, a non-macrolide antibiotic. We conducted a pre-post analysis using data from patients assigned male sex at birth who were diagnosed with NGU at the PHSKC SHC between October 1, 2013 and December 31, 2023 to evaluate the impact of introducing MG testing and targeted treatment on persistent NGU cases. Data were collected from electronic health records. Statistical significance of differences in characteristics between Period 1 (prior to the introduction of MG testing for acute NGU cases and MG-specific therapy) and Period 2 (after the introduction of MG testing for acute NGU cases and MG-specific therapy) and visits with acute NGU and persistent NGU were assessed using Pearson's chi-square or Fisher's exact tests and Wilcoxon rank sum tests. Multivariable Poisson regression with generalized estimating equations and robust standard errors was used to estimate the prevalence ratio (PR) of visits for persistent NGU in Period 2 relative to Period 1. Among 5,060 NGU visits over both periods of time, 205 (4.1%) were classified as persistent NGU. Adjusting for race/ethnicity, Chlamydia trachomatis nucleic acid amplification test results at acute NGU visits, and human immunodeficiency virus status, the introduction of MG testing plus MG-specific therapy (Period 2) was associated with a non-significant 12% reduction in the prevalence of persistent NGU relative to the time period prior to this introduction (Period 1; adjusted PR: 0.88, 95% confidence interval: 0.67-1.16, p=0.353). Introducing MG testing and sequential doxycycline and moxifloxacin treatment for MG infections was associated with a modest, non-significant reduction in persistent NGU. These findings suggest that recommending MG testing at first presentation of NGU and providing targeted treatment for MG infections may not result in fewer persistent NGU cases.