Multicenter Clinical Evaluation of a Novel Multiplex Real-Time PCR (qPCR) Assay for Detection of Fluoroquinolone Resistance in Mycoplasma genitalium

Mycoplasma genitalium causes a common sexually transmitted infection with a marked propensity to develop antimicrobial resistance. As few treatment options exist, this poses significant challenges to clinicians. Recent diagnostic advances have resulted in tests that report the simultaneous detection of M. genitalium and any resistance to macrolides, the first-line treatment. This allows for therapy to be tailored to the individual, thereby optimizing treatment outcomes. However, resistance to fluoroquinolones, the second-line treatment, is increasing in M. genitalium. In this study, we describe a new assay, MG+parC (beta), which simultaneously reports the detection of M. genitalium and five parC mutations that have been associated with resistance to fluoroquinolones. These mutations affect the amino acid sequence of ParC at residues S83R (A247C), S83I (G248T), D87N (G259A), D87Y (G259T), and D87H (G259C). The study tested the MG+parC (beta) assay with 202 M. genitalium-positive clinical samples from Australia (n = 141) and Spain (n = 61). Compared to Sanger sequencing, the assay performed with a kappa value of 0.985 (95% confidence interval [CI], 0.955 to 1.000), with a mutation detection sensitivity of 97.6% (95% CI, 87.4 to 99.9), and specificity of 100.0% (95% CI, 97.7 to 100.0). Fluoroquinolone resistance-associated mutations in parC targeted by the assay were more prevalent among the Australian cohort (23.4% [95% CI,16.3 to 31.8]) compared to the Spanish population (8.8% [95% CI, 2.9% to 19.3%]) (P = 0.019). The MG+parC (beta) kit is a simple and reliable method for simultaneous detection of M. genitalium and fluoroquinolone resistance-associated mutations in clinical settings. This novel diagnostic tool may extend the utility of the second line of antimicrobial therapies in M. genitalium infection.