Molecular detection of Mycoplasma genitalium in endocervical swabs and associated rates of macrolide and fluoroquinolone resistance in Hong Kong

Introduction: There is a global trend of increasing macrolide and fluoroquinolone resistance in Mycoplasma genitalium (MG), such that international guidelines recommend molecular detection of resistance if a patient has MG-positive test results. Tests for MG are not routinely performed in Hong Kong. This study examined the detection of MG in endocervical swabs and the associated macrolide and fluoroquinolone resistance rates. Methods: Endocervical swabs received from two sexual health clinics in Hong Kong for routine assessments of Chlamydia trachomatis and Neisseria gonorrhoeae were also subjected to detection of MG. All MG-positive samples were tested for resistance-mediating mutations in 23S rRNA, parC, and gyrA genes. Laboratory records and past results for each patient were analysed. Results: In total, endocervical swabs from 285 patients were included in this study. Mycoplasma genitalium was detected in swabs from 21 patients (7.4%) by real-time polymerase chain reaction with a commercial kit. Among MG-positive samples which were successfully analysed further, macrolide resistance-mediating mutations in 23S rRNA were found in 42.1% (8/19); fluoroquinolone resistance-related mutations in parC and gyrA were found in 65% (13/20) and 0% (0/20), respectively. All macrolide-resistant MG strains were also fluoroquinolone-resistant (42.1%, 8/19). No assessed factors were associated with the detection of MG or resistance-related mutations. Conclusion: In Hong Kong, MG was detected in endocervical swabs from 7.4% of patients in sexual health clinics, with high rates of macrolide and fluoroquinolone resistance. These findings warrant careful review of testing, clinical correlation, and treatment strategies for MG in the context of increasing antibiotic resistance.