Clinical evaluation of three commercial PCR assays for the detection of macrolide resistance in Mycoplasma genitalium

As macrolide resistance in Mycoplasma genitalium is increasing worldwide, macrolide resistance-associated mutations should be assessed in M. genitalium-positive specimens. New commercial kits are available for detection of macrolide resistance concurrently with M. genitalium. We prospectively evaluated the handling and clinical performance of three commercial kits for detection of macrolide resistance in M. genitalium. Between August and December 2018, remnants of all urogenital specimens determined to be M. genitalium-positive using an in-house real-time PCR assay were prospectively collected at the French National Reference Center for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital. The internal control of each kit was added to the primary specimen before DNA extraction, and the absence of amplification inhibition associated with the addition of the three internal controls was assessed. Specimens were evaluated by four assays: ResistancePlus® MG assay (SpeeDx), S-DiaMGResTM assay (Diagenode), RealAccurate® TVMGres assay (PathoFinder), and amplification and sequencing of the 23S rRNA gene (reference assay). Overall, 195 M. genitalium-positive specimens were assessed. The positive agreement of M. genitalium detection for each kit ranged between 94.8% and 96.4%. Among 154 specimens with M. genitalium positivity as detected by the three commercial kits and 23S rRNA sequencing data, the clinical sensitivity and specificity ranges of the three commercial kits for detecting macrolide resistance-associated mutations was 95–100% and 94.6–97.3%, respectively. The sensitivity and specificity values were similar among the kits. The launch of three easy-to-use sensitive and specific commercial kits for simultaneous detection of M. genitalium and macrolide resistance will be useful for resistance-guided therapy.