Performance of Allplex™ MG & AziR Assay for Detecting Macrolide-Resistant Mycoplasma genitalium.

BACKGROUND

Mycoplasma genitalium is a sexually transmitted pathogen for which azithromycin is recommended as the first-line therapy. However, the prevalence of macrolide resistance has increased globally, reaching peak levels in Asia-Pacific countries. Macrolide resistance-guided therapy (MRT) is cost-effective, with minimal collateral damage and a high cure rate. We aimed to validate the performance of the Allplex™ MG & AziR Assay (AziR), which was designed to detect genetic variations in MRT.

METHODS

Using 279 M. genitalium-positive genitourinary samples, the performance of the AziR assay was compared with that of Sanger sequencing of the 23S rRNA gene of M. genitalium.

RESULTS

The AziR assay targeting positions 2058 and 2059 in the 23S rRNA gene revealed that 133 and 146 cases, respectively, carried the wild and mutant types of adenosine, while sequencing detected the wild and mutant types in 134 and 145 cases, respectively. The AziR assay demonstrated a sensitivity of 100% (95% confidence interval [CI], 0.968-1) and specificity of 99.254% (95% CI, 0.953-1) in distinguishing wild type from mutant variants. Of the 279 samples, only six showed genetic discrepancies between the two tests: one wild type by sequencing was found to have A2059G by the AziR assay, two A2059Gs were discordant as A2058Ts, one A2059G was discordant as A2058G, and two A2058Gs by sequencing were reported as A2059Gs by the AziR assay.

CONCLUSION

Our results show that the AziR assay can identify specific mutants in a single reaction and demonstrates high sensitivity and specificity for detecting macrolide resistant M. genitalium. Therefore, the AziR assay can be reliably used for MRT.