Evaluation of the ResistancePlus MG FleXible Assay for Detection of Wild-Type and 23S rRNA-Mutated Mycoplasma genitalium Strains

• Published in: Journal of clinical microbiology Vol. 58; no. 3
• Main Authors: Drud, Suhella Tulsiani, Njuguna, Peter, Ebeyan, Samantha, Erskine, Simon, Holm, Mette, Johansson, Susanne Cramer, Tan, Lit Yeen, Jensen, Jorgen Skov
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 24-02-2020
• Subjects: Anti-Bacterial Agents - pharmacology; Bacteriology; Drug Resistance, Bacterial - drug effects; Humans; Macrolides - pharmacology; Mycoplasma genitalium - drug effects; Mycoplasma genitalium - genetics; Mycoplasma Infections - diagnosis; Reproducibility of Results; RNA, Ribosomal, 23S - genetics; detection; diagnostics; near-patient; Mycoplasma genitalium; ResistancePlus MG FleXible; molecular assay; GeneXpert Dx; macrolide resistance
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.01900-19

Antibiotic resistance in
is rising globally, and resistance-guided diagnostics can facilitate targeted and timely treatment. The ResistancePlus MG FleXible (RPMG Flex) assay for the detection of
and macrolide resistance-mediating mutations (MRMM) was evaluated for analytical sensitivity, specificity, reproducibility, and inhibition in the presence of interfering substances by simulating
-negative pooled urine and swab matrices with
cultures. Furthermore, the clinical sensitivity of the assay was evaluated and compared with a reference real-time PCR assay. The analytical sensitivity of the RPMG Flex assay was 157 genomes/ml for wild-type (WT) and 387 genomes/ml for MRMM strains in both matrices. For clinical specimens, the RPMG assay had an overall sensitivity of 96.1% (95% urine: 10/10 WT, 9/10 MRMM; 96.5% swab: 25/26 WT, 26/29 MRMM) compared to 85.7% for the MgPa/MagNAPure24 assay (95% urine: 19/20; 87% swab: 48/57). Clinical specificity was 100% for urine and 98.5% for swab specimens, respectively. No inhibition due to the presence of any of the tested interfering substances was observed. The RPMG Flex assay was more sensitive than the reference MgPa assay, in particular, for swab specimens. The implementation of this assay may increase ease of use and considerably decrease hands-on time for sample preparation compared to a standard block-based assay. The RPMG Flex assay for the GeneXpert Dx system provides a much-needed platform for the simultaneous detection of MG and MRMM and may thereby facilitate resistance-guided therapy for
infections.