A national survey found that more than 40% of Mycoplasma genitalium (MG) infections in Americans aged 14–59 carry resistance to macrolide antibiotics — the first-line treatment — translating to roughly 1.4 million resistant infections. Resistance was highest among people under 25. Experts are urging resistance testing before prescribing to stay ahead of a growing threat.
A new analysis of national survey data reveals a troubling antibiotic resistance trend: more than 40% of Mycoplasma genitalium (MG) infections in Americans aged 14–59 carry mutations that make them resistant to macrolide antibiotics like azithromycin — the standard first-line treatment. That translates to an estimated 1.4 million macrolide-resistant MG infections in the US, based on 2017–2018 NHANES data.
The findings raise red flags for clinicians, especially since resistance was far more common in younger patients and those with recent new sexual partners. On the brighter side, no quinolone resistance — which would limit the backup drug moxifloxacin — was detected in any tested specimens.
MG is a sexually transmitted infection that's notoriously tricky to treat, and widespread macrolide use has fueled resistance. As MG testing expands and moxifloxacin use grows, quinolone resistance could follow. Experts recommend pairing diagnostic testing with resistance testing to guide treatment decisions and preserve the effectiveness of remaining options.
