(ÖGDV Jahrestagung 2025 & IUSTI-Europe 2025)
Katharina Schwarz, Miriam Kyska, Angelika Stary
Outpatients Centre for Diagnosis of Infectious Venero-dermatological Diseases, Vienna, Austria
Introduction
Resistances against Mycoplasma genitalium (M. genitalium) are an increasing problem for patients with M. genitalium infections. Testing for resistance proof of M. genitalium for both, azithromycin and moxifloxacin, is commercially available.
The Allplex MG&AziR Assay and Allplex MG&MoxiR Assay (Seegene, Republic of Korea) are multiplex real time PCR assays that simultaneously detect and identify M. genitalium and 6 mutations in 23s rRNA gene related to azithromycin resistance and 6 mutations in parC gene related to moxifloxacin resistance.
Aim of the evaluation was to perform the resistance proof with both Allplex Assays for samples tested positive for M. genitalium with the Alinity m STI Assay (Abbott, USA).
Methods
In 2024 and 2025, 45 patients attending the Outpatients Centre with a positive result for M.genitalium in the Alinity m STI assay were included in the study. Resistance was evaluated via PCR by the Allplex MG&AziR Assay and Allplex MG&MoxiR Assay for azithromycin and moxifloxacin.
Results
Altogether, for all samples positive in the Alinity m STI Assay as well as in both Allplex Assays, resistance was detected for azithromycin in 85.30%, for moxifloxacin in 51.35% (Figure 1) and for both antibiotics in 48.49%, respectively. A high agreement of 100% for the detection of M. genitalium between the Alinity m assay and both Allplex Assays was observed for samples with cycle turn-values (CT-values) of the Alinity m assay below 25.00. For CT-values between 25.00 and 35.00 of positive Alinity m results, 82.8% and 89.7% respectively, revealed also a positive result for the Allplex MG&AziR Assay and Allplex MG&MoxiR Assay. For CT-values of the Alinity m Assay above 35.00, low numbers of concordant positive results (33.3% and 44.4%, respectively) were observed for the Allplex Assays (Figure 2).
Conclusion
A high resistance for azithromycin (85.30%) and moxifloxacin (51.35%) or both antibiotics (48.49%) was observed in Austria which confirms the importance of resistance proof, which conveniently was performed by the Allplex Assays. For Alinity m positive samples with a high CT level, the Allplex Assays might fail to detect an infection with M. genitalium, also missing to detect resistances against standard antibiotics.
