Efficacy of pristinamycin in the treatment of people with Mycoplasma genitalium infection experiencing resistance-guided treatment failure: an observational study.

OBJECTIVE

To evaluate the efficacy of pristinamycin in treating Mycoplasma genitalium infection among patients who experienced failure of resistance-guided treatment regimens.

METHODS

This observational study reviewed pharmaceutical and clinical records of patients who received pristinamycin via the named-patient mechanism at a London sexual health service between October 2019 and February 2025. Eligible participants had documented clinical and/or microbiological failure following resistance-guided therapy. Data collected included demographics, sexuality, infection site, macrolide resistance results, prior antibiotic exposure and tetracycline pretreatment. The primary outcome was microbiological cure, defined as a negative test-of-cure ≥4 weeks post treatment. The secondary outcome was clinical cure, defined as resolution of symptoms in the absence of a confirmatory test. We compared proportions with Fisher's exact test for 2×2 comparisons and a single global χ2 test for multicategory comparisons, reporting relative risks with 95% CIs.

RESULTS

Sixty-eight patients were identified; 87% were male, 57% were men who have sex with men, and the mean age was 37 years. Nearly all (97%) had macrolide-resistant infections. Most (81%) had previously received moxifloxacin and the median number of prior antimicrobial courses was three. Microbiological cure was achieved in 71% (48/68; 95% CI 58% to 81%) and clinical cure in 76% (52/68; 95% CI 65% to 86%). When stratified by the use or non-use of tetracycline pretreatment and by the indication for the test, no statistically significant difference in either microbiological or clinical cure was observed.

CONCLUSIONS

Pristinamycin achieved microbiological and clinical cure rates of 71-76% in patients with macrolide-resistant M. genitalium infection. These findings align with previously published observational data, supporting pristinamycin as an effective and tolerable third-line treatment option following macrolide-based and quinolone-based regimen failure. Development of standardised algorithms is warranted to optimise management of resistant M. genitalium infection.