Fröberg, GabrielleMaurer, Florian P.Chryssanthou, ErjaFernström, LouiseBenmansour, HanaaBoarbi, SamiraMengshoel, Anne TorunnKeller, Peter M.Viveiros, MiguelMachado, DianaFitzgibbon, Margaret M.Mok, SimoneWerngren, JimCirillo, Daniela MariaAlcaide, FernandoHyyryläinen, Hanne-LeenaAubry, AlexandraAndres, SönkeNadarajan, DarshaaliniSvensson, ErikTurnidge, JohnGiske, Christian G.Kahlmeter, GunnarCambau, Emmanuellevan Ingen, JakkoSchön, ThomasEUCAST AMSTESCMYC study groups2023-08-252023-08-252023-02-201198-743Xhttps://hdl.handle.net/2445/201520Objective: For non-tuberculous mycobacteria (NTM), minimum inhibitory concentration (MIC) distributions of wild-type isolates have not been systematically evaluated despite their importance for establishing antimicrobial susceptibility testing (AST) breakpoints. Methods: We gathered MIC distributions for drugs used against the Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MAB) obtained by commercial broth microdilution (SLOMYCOI and RAPMYCOI) from 12 laboratories. Epidemiological cut-off values (ECOFFs) and tentative ECOFFs (TECOFFs) were determined by EUCAST methodology including quality control (QC) strains. Results The clarithromycin ECOFF was 16 mg/L for M. avium (n=1271) whereas TECOFFs were 8 mg/L for M. intracellulare (n=415) and 1 mg/L for MAB (n=1014) confirmed by analysing MAB subspecies without inducible macrolide resistance (n=235). For amikacin, the ECOFFs were 64 mg/L for MAC and MAB. For moxifloxacin, the WT spanned >8 mg/L for both MAC and MAB. For linezolid, the ECOFF and TECOFF were 64 mg/L for M. avium and M. intracellulare, respectively. Current CLSI breakpoints for amikacin (16 mg/L), moxifloxacin (1 mg/L) and linezolid (8 mg/L) divided the corresponding WT distributions. For QC M. avium and M. peregrinum, ≥95% of MIC values were well within recommended QC ranges. Conclusion : As a first step towards clinical breakpoints for NTM, (T)ECOFFs were defined for several antimicrobials against MAC and MAB. Broad wild-type MIC distributions indicate a need for further method refinement which is now under development within the EUCAST subcommittee for anti-mycobacterial drug susceptibility testing. In addition, we showed that several CLSI NTM breakpoints are not consistent in relation to the (T)ECOFFs.7 p.application/pdfengcc by (c) Fröberg, Gabrielle et al., 2023https://creativecommons.org/licenses/by/4.0/Medicaments antibacteriansResistència als medicamentsMicobacterisAntibacterial agentsDrug resistanceMycobacteriainfo:eu-repo/semantics/article7325622023-08-25info:eu-repo/semantics/openAccess36813087