TABLE 1.

Suggested broth microdilution breakpoints for rapidly growing mycobacteria^a

Drug	MIC (μg/ml) for category:
	Susceptible	Intermediate	Resistant
Amikacinb	≤16	32	≥64
Cefoxitin	≤16	32 [32–64]	≥64 [≥128]
Ciprofloxacinb	≤1	2	≥4
Clarithromycinb	≤2	4	≥8
Doxycycline	≤1	2–8	≥16
Imipenemb	≤4	8	≥16
Sulfamethoxazolebc	≤32		≥64
Tobramycin (M. chelonae only)	≤4	8	≥16

^aBreakpoints recommended by the American Society for Microbiology Clinical Procedures Handbook (3). Proposed new breakpoints are in brackets. 

^bNCCLS recommended breakpoint for bacteria that grow aerobically (8a). 

^cNCCLS recommendations are for trimethoprim-sulfamethoxazole at similar but not identical concentrations.