MALDI-TOF Mass Spectrometry
By setting a LSV cut-off at ≥ 2.0, MALDI-TOF MS was able to correctly identify 80 isolates out of 111 (72.1%) appertaining to 19 species using sequence analysis (16s rRNA gene, rpoB and hsp65 ). By lowering the cut-off for species identification at ≥ 1.8 as previously proposed for mycobacterial species (Alcaide et al., 2018, Pranada, 2015), 100 isolates (90.1%) from the same 19 species were correctly assigned (Table 1). Two isolates, one M. vulneris misidentified as M. colombiense(LSV 2.08) and a second one, presumably representing a new species and misidentified as M. arupense (LSV 1.81) led to discrepant results (Supplementary material S2-S4). The remaining 9 isolates, classified as “no identification possible” by MALDI-TOF MS, were identified by sequence analysis as M. colombiense (3/3 isolates) M. scrofulaceum (2/2 isolates), M. monacense and M. terraecomplex (one isolate each), and two additional undescribedMycobacterium spp..