Towards clinical breakpoints for non-tuberculous mycobacteria – Determination of epidemiological cut off values for the Mycobacterium avium complex and Mycobacterium abscessus using broth microdilution

• DOI: 10.1016/j.cmi.2023.02.007
• Publication Date: 2023-02-20T18:00:13Z
• Authors: Gabrielle Fröberg; Florian P. Maurer; Erja Chryssanthou; Louise Fernström; Hanaa Benmansour; Samira Boarbi; Anne Torunn Mengs...; Peter Michael Keller; Miguel Viveiros; Diana Machado; Margaret M. Fitzg...; Simone Mok; Jim Werngren; Daniela Maria Cir...; Fernando Alcaide; Hanne-Leena Hyyry...; Alexandra Aubry; Sönke Andres; Darshaalini Nadar...; Erik Svensson; John Turnidge; Christian G. Giske; Gunnar Kahlmeter; Emmanuelle Cambau; Jakko van Ingen; Thomas Schön
• Keywords: Broth microdilution; Mycobacterium abscessus; Amikacin; Nontuberculous Mycobacteria

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. We gathered MIC drugs used against the Mycobacterium avium complex (MAC) and abscessus (MAB) obtained by commercial broth microdilution (SLOMYCOI RAPMYCOI) from 12 laboratories. Epidemiological cut-off values (ECOFFs) tentative ECOFFs (TECOFFs) were determined EUCAST methodology including quality control (QC) strains. The clarithromycin ECOFF was 16 mg/L M. (n = 1271) whereas TECOFFs 8 intracellulare 415) 1 MAB 1014) confirmed analysing subspecies without inducible macrolide resistance 235). amikacin, 64 MAC MAB. moxifloxacin, WT spanned >8 both linezolid, TECOFF intracellulare, respectively. Current CLSI breakpoints amikacin (16 mg/L), moxifloxacin (1 mg/L) linezolid (8 divided corresponding distributions. QC peregrinum, ≥95% well within recommended ranges. As a first step towards clinical NTM, (T)ECOFFs defined several antimicrobials Broad indicate need further method refinement which is now under development subcommittee anti-mycobacterial drug testing. In addition, we showed that NTM are consistent in relation to (T)ECOFFs.