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Table. 2. Table 2

Identification of NTM isolates using ASTA microIDSys MALDI-TOF MS with the MycoDB v1.95s and upgraded MycoDB v2.0-beta databases, along with percentages of species correctly identified using ASTA MALDI-TOF MS with MycoDB v2.0-beta

NTM species confirmed by reverse blot hybridization assay (reference method)	N	MALDI-TOF MS identification results

		MycoDB v1.95s				MycoDB v2.0-beta

		≥140 (N=33)	130–139 (N=54)	Total (N=124)	Correctly identified^* isolates N (%)	≥140 (N=117)	130–139 (N=5)	Total (N=124)	Correctly identified^* isolates N (%)
M. fortuitum group	5	1	1	2	1 (20.0)	5	0	5	5 (100.0)
M. abscessus	53	12	14	26	12 (22.6)	50	3	53	50 (94.3)
M. abscessus subsp. abcessus	39
M. abscessus subsp. massiliense	14
M. kansasii	5	1	4	5	1 (20.0)	5	0	5	5 (100.0)
M. avium	35	9	27	36	9 (25.7)	32	1	33^†	32 (91.4)
M. intracellulare	22	10	7	17	10 (45.5)	20	1	21^‡	20 (90.9)
M. chelonae	0	0	1	1^§	0 (0.0)	0	0	0
M. gordonae	3	0	0	0	0 (0.0)	4	0	4^‡	3 (100.0)
M. szulgai	1	0	0	0	0 (0.0)	1	0	1	1 (100.0)
Invalid identification^ll				37				2^†

Abbreviations: NTM, nontuberculous mycobacteria; MALDI-TOF MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

*Only isolates with an identification score ≥140 were deemed correctly identified; ^†Two M. avium isolates were unidentified by MALDI-TOF MS; ^‡One M. intracellulare isolate was misclassified as M. gordonae by MALDI-TOF MS; ^§One M. chelonae isolate misidentified by MALDI-TOF MS was confirmed as M. abscessus subsp. abscessus by the reference method; ^llIsolates with an identification score <130 were labeled as invalid identifications.

Ann Lab Med 2022;42:358~362 https://doi.org/10.3343/alm.2022.42.3.358