Species Identification and Clarithromycin Susceptibility Testing of 278 Clinical Nontuberculosis Mycobacteria Isolates

Table 3

Clarithromycin susceptibility testing result of different species.

Subspecies	Incubation; days	Susceptible; breakpoint	Moderately; susceptible; breakpoint	Resistant; breakpoint	MIC range; (μg/mL)	MIC50; (μg/mL)	MIC90; (μg/mL)	Number (%) of; susceptible strains	Number (%) of; moderately; susceptible strains	Number (%) of; resistant; strains
M. abscessus subsp.  abscessus; ( = 45)	14	≤2	4	≥8	1–>32	>32	>32	5 (10%)	3 (7%)	37 (83%)
M. abscessus subsp. massiliense; ( = 25)	14	≤2	4	≥8	≤0.0625–>32	0.25	0.25	24 (96%)	0 (0%)	1 (4%)
M. fortuitum; ( = 23)	3	≤2	4	≥8	≤0.0625–>32	0.5	4	21 (92%)	1 (4%)	1 (4%)
MAC; ( = 131)	7	≤8	16	≥32	≤0.0625–>32	0.5	8	124 (95%)	1 (1%)	6 (4%)
M. kansasii; ( = 34)	7	≤16	—	>16	≤0.0625–16	≤0.0625	1	34 (100%)	—	0 (0%)