(P251) The real magnitude of antimicrobial resistance of Mycoplasma genitalium in Belgium.

Background: Due to the emergence of multidrug-resistant (MDR) Mycoplasma genitalium globally, Belgian antimicrobial resistance (AMR) patterns of M. genitalium are investigated by the National Reference Center of STIs (NRC-STI) since 2018. Resistance to macrolides (83.7%) and fluoroquinolones (46.5%) was rising yearly and MDR was estimated to be almost 45% in Belgium. However, samples are only sent to the NRC-STI on a voluntary basis and representative/robust national AMR data are lacking. The aim of this study was to assess the real magnitude of M. genitalium AMR by implementing a prospective collection of M. genitalium positive samples by different diagnostic laboratories.

Methods: M. genitalium positive samples collected from July-November 2022 in Belgian laboratories were sent to the NRC-STI. The presence of macrolide and fluoroquinolones resistance associated mutations (RAMs) was tested using Sanger sequencing of the 23SrRNA and parC gene (alterations in ParC S83I, S83R, D87N, D87Y). Differences in resistance patterns between geographical location, gender, transmission, and the presence of symptoms were assessed via Fisher’s exact test and logistic regression.

Results: Sequencing for both macrolide and fluoroquinolone RAMs was successful for 198 samples shipped by 20 laboratories. The socio-demographic characteristics and AMR patterns of the samples are tabulated in Table 1. Almost all samples were of urogenital origin (189/198; 95.5%) and predominantly from women (135/198; 68.2%). Resistance patterns did differ among the regions, gender, and transmission, however, in the multivariate regression model, resistance patterns differed only borderline between regions. Macrolide resistance (aOR:0.49; 95%CI: 0.25-0.96) and MDR (aOR: 0.40; 95%CI: 0.16-0.99) were less likely found in Wallonia compared to Flanders.

Conclusion: Although MDR M. genitalium was still found in 1/5^th of the cases, we showed that MDR M. genitalium was previously overestimated. While macrolide resistance was still more frequently found among men (65.6%), macrolide resistance is increasing among women and almost reaches 50%. One in four of the samples harbored RAMs to fluoroquinolones. Interestingly, differences between regions were noted which may be explained by variations in population density. Implementation of a prospective surveillance program of resistance patterns in M. genitalium is recommended to estimate the real burden of MDR in Belgium.