Key findings from the 2024 Mycoplasma genitalium Antimicrobial Resistance Surveillance (MARS) programme

Abstract

Background

Mycoplasma genitalium is a sexually transmitted pathogen of public health concern due to antimicrobial resistance to the recommended first- and second-line treatments, azithromycin and moxifloxacin. The M. genitalium Antimicrobial Resistance Surveillance (MARS) programme monitors resistance trends in England to inform clinical management and public health policy. Here, we summarise key findings from MARS 2024.

Methods

From 1^st March to 30^th June 2024, M. genitalium-positive specimens were collected at 32 sentinel sexual health services across England. Specimens were tested for molecular markers predictive of macrolide and fluoroquinolone resistance in the 23S rRNA and parC genes, respectively. In non-wildtype parC specimens, the gyrA gene was also sequenced. AMR data were linked to patient demographic, clinical, and behavioural data.

Results

The MARS 2024 sample included 1,049 individuals; 65.6% were male. Where resistance results were available, 63.6% of specimens were macrolide-resistant, 16.7% were fluoroquinolone resistant, and 13.7% were dual-resistant to both antimicrobials. Compared to MARS 2023, high levels of macrolide resistance remain, with increasing fluoroquinolone (p = 0.008) and dual resistance (p = 0.024).

Most individuals (87.3%) were prescribed the recommended first- or second-line treatments and 80.8% received doxycycline as a pre-treatment. Resistant genotypes were common among those with a positive test-of-cure (TOC): 90.9% of individuals with a positive TOC following azithromycin were infected with a macrolide-resistant strain, and 51.6% of those with a positive TOC following moxifloxacin were infected with a fluoroquinolone-resistant strain. However, genotype did not consistently predict TOC outcome, as 14.6% of those with negative TOCs following azithromycin had macrolide-resistant infections and 16.6% of those with negative TOCs following moxifloxacin had fluoroquinolone-resistant infections.

Conclusions

MARS 2024 is the largest dataset examining antimicrobial resistance in M. genitalium in England, confirming widespread macrolide resistance and increasing levels of fluoroquinolone and dual resistance, underscoring the importance of national surveillance to inform management guidelines.