Prevalence of macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium in Hong Kong

Abstract

Background: Mycoplasma genitalium (MG) is a common cause of non-gonococcal urethritis (NGU) and the surge in MG antibiotics resistance is alarming. In Hong Kong, NGU is the most prevalent sexually transmitted infection (STI) in males. However, the local prevalence of MG and the burden of antimicrobial resistance remain unknown. This study aimed to determine the prevalence of antibiotic resistance in MG among STI male patients in Hong Kong. Methods and materials: Male patients attending a sexually transmitted diseases clinic for treatment of NGU and presenting with urethritis were included. First-void urine specimens were collected and screened for MG infection by real-time PCR (Genesig, United Kingdom). M. genitalium-positive samples were tested for macrolide resistance-associated mutations in the 23S rRNA gene using the ResistancePlus MG assay (SpeeDx, Australia), and fluoroquinolone resistance-associated genetic markers in gyrA and parC by PCR and sequencing. Results: The prevalence of MG in male patients with symptomatic urethritis was 10.8% (17/157). Among 17 men with MG infection, 5 (29.4%) were initially treated with azithromycin and 4 (23.5%) on moxifloxacin. Overall, 11 patients (64.7%) harbored macrolide resistance-associated mutations in the 23S rRNA gene. The GyrA and ParC genes were successfully amplified and sequenced in 15 MG-positive cases, of which 60.0% (9/15) possessed fluoroquinolone resistance-associated mutations (S83I or D87Y) in parC. The presence of MG with alterations in both 23S rRNA gene and parC, potentially associated with treatment failure with macrolide and fluoroquinolone regimens, was 46.7% (7/15). Conclusion: The emergence of MG carrying both macrolide and fluoroquinolone resistance-associated mutations is raising concern about incurable MG for which recommended therapies would be ineffective. This study indicates further antimicrobial drug resistance surveillance would be needed to limit the spread of macrolide and fluoroquinolone resistance in MG in Hong Kong.