TOPLINE

Macrolide resistance mutations (MRMs) were detected in more than 40% of Mycoplasma genitalium infections among people aged 14-59 years in the US during 2017-2018, representing approximately 1.4 million macrolide-resistant infections. Quinolone resistance-associated mutations (QRAMs) were not detected in any of the tested specimens.

METHODOLOGY

• Researchers conducted a cross-sectional analysis of urine specimens from participants aged 14-59 years in the 2017-2018 National Health and Nutrition Examination Survey (NHANES) to estimate the population-level prevalence of M genitalium antimicrobial resistance.
• Data were collected from the civilian, noninstitutionalized US population through NHANES, which uses a clustered sampling strategy involving household interviews and health examinations at mobile examination centers.
• MRMs in the 23S rRNA gene were detected using reverse transcriptase polymerase chain reaction followed by PyroMark24 sequencing, while QRAMs in the parC and gyrA genes were detected using conventional polymerase chain reaction followed by Sanger sequencing.
• Of 58 M genitalium-positive urine specimens, 49 specimens (84.5%) yielded MRM results, 41 (70.7%) yielded parC QRAM results, and 42 (72.4%) yielded gyrA QRAM results.
• Researchers estimated the weighted prevalence of MRMs overall and across sociodemographic, behavioral, and clinical subgroups and calculated prevalence ratios (PRs).

TAKEAWAY

• Weighted MRM prevalence was 42.7%, corresponding to about 1.4 million macrolide-resistant M genitalium infections; the most common mutation was A2058G, with a weighted prevalence of 26.9%.
• MRM prevalence was significantly higher among people younger than 25 years than among those aged 25 years or older (64.3% vs 30.7%) and decreased by 5% for each 1-year increase in age (PR, 0.95; 95% CI, 0.92-0.98).
• The highest MRM prevalence was observed among people who had received mental health care (92.9%; PR, 2.7; 95% CI, 1.53-5.12) or those who reported a new sex partner in the past year (76.1%; PR, 2.7; 95% CI, 1.34-5.34).
• No QRAMs were detected in the parC gene (0 of 41 specimens tested) or the gyrA gene (0 of 42 specimens tested).

IN PRACTICE

"The high MRM prevalence likely resulted from widespread use of macrolides. Although QRAMs were not detected, quinolone resistance has increased in other countries and will increase in the US as MG [Mycoplasma genitalium] testing and moxifloxacin treatment expand. MRM testing is increasingly available. It should ideally accompany diagnostic testing for MG and moxifloxacin should only be prescribed when azithromycin cannot be used," the authors of the study wrote.

SOURCE

The study was led by Lisa E. Manhart, PhD, MPH, Department of Epidemiology, School of Public Health, University of Washington, Seattle. It was published online on October 9, 2026, in Open Forum Infectious Diseases.

LIMITATIONS

The small number of M genitalium-positive specimens resulted in limited statistical power and high variances, particularly for population subgroup estimates, which might be unstable. Specimens were unavailable for some M genitalium-positive participants, and some of the specimens that were tested did not produce results, potentially introducing residual bias despite weighted analysis. 

DISCLOSURES

This study was supported by grants from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. One author reported receiving research funding and materials from Hologic and Nabriva Therapeutics as well as travel support from Hologic. Another author reported receiving research supplies from Hologic and research funding from Gilead Sciences, unrelated to this work. A third author served on scientific advisory boards for Abbott and bioMérieux and received speaker honoraria from Hologic and LEO Pharma. The remaining authors reported no conflicts of interest. Full author disclosures are reported in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.