TOPLINE:

Among women treated for Chlamydia trachomatis infection, a single‑dose azithromycin or 7‑day doxycycline regimen eradicated Mycoplasma genitalium coinfections in majority of patients.

METHODOLOGY:

• Researchers included 281 women from a randomized controlled trial to evaluate the effect of standard C trachomatis treatment with azithromycin vs doxycycline on M genitalium coinfection, including eradication, persistence, and incidence.
• Overall, 131 patients received a single 1-g dose of azithromycin and 150 received 100 mg doxycycline twice daily for 7 days.
• M genitalium was detected in vaginal swabs using quantitative real-time polymerase chain reaction; macrolide and quinolone resistance were assessed by sequencing the 23S rRNA and parC genes, respectively.
• Patients were evaluated at baseline and 6 weeks post-treatment. M genitalium eradication was defined as a negative result at follow-up assessment in those who tested positive for M genitalium at baseline.
• Persistence of M genitalium was defined as detection of the same strain at 6 weeks or in patients reporting no sexual activity or consistent condom use; an incident infection was defined as a negative result at baseline and a positive result at 6 weeks after initiation of C trachomatis treatment.

TAKEAWAY:

• Overall, M genitalium was detected in 13.9% of women, with 16% of women in the azithromycin group and 12% of women in the doxycycline group (P = .39).
• At 6 weeks, the M genitalium eradication rate was higher in the azithromycin group than in the doxycycline group (85.7% vs 55.6%), but the difference was not statistically significant.
• Baseline resistance rates were similar between the groups, with macrolide resistance at 11.1% in the azithromycin group vs 26.7% in the doxycycline group and quinolone resistance at 11.8% vs 16.7% in the respective groups.
• No significant between-group differences were observed in persistence or incident infections at the follow-up assessment.

IN PRACTICE:

“Our findings indicate that in our cohort of asymptomatic women treated for CT [Chlamydia trachomatis] with single-dose azithromycin or a 7-day course of doxycycline, concurrent MG [Mycoplasma genitalium] was eradicated in most cases,” the authors wrote.

SOURCE:

This study was led by Chloé Le Roy, University of Bordeaux, Bordeaux, France. It was published online on January 20, 2026, in the International Journal of Infectious Diseases.

LIMITATIONS:

Only 281 of the 460 initially enrolled women had paired vaginal swabs available at baseline and 6 weeks. Low bacterial loads of M genitalium often hindered genotyping and detection of resistance mutations, particularly in the doxycycline group. The high eradication rates may have reflected spontaneous clearance or limited assay sensitivity.

DISCLOSURES:

The randomized controlled trial was funded by Programme Hospitalier de Recherche Clinique National 2016. The authors declared having no conflicts of interest.

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