Table 1.

MIC₅₀ and MIC₉₀ of polymyxins.

Species	PMB						CST
	AD		rBMD*		BMAD		AD		rBMD*		BMAD
μg/mL	MIC50	MIC90	MIC50	MIC90	MIC50	MIC90	MIC50	MIC90	MIC50	MIC90	MIC50	MIC90
E. coli	0.5	1	1	2	0.5	1	0.5	0.5	1	2	0.25	0.5
K. pneumoniae	1	2	2	2	1	2	0.5	1	1	2	0.5	1
E. cloacae	1	1	2	4	0.5	1	1	1	1	2	0.5	1
K. aerogenes	1	1	2	2	0.5	0.5	0.5	0.5	1	2	0.25	0.5
A. baumannii	1	1	2	2	0.5	1	0.5	0.5	1	2	0.5	1
P. aeruginosa	2	2	2	4	1	1	2	2	2	4	1	2

PMB: polymyxin B; CST: colistin; AD: agar dilution; rBMD: reference broth microdilution; BMAD: broth macrodilution. *: using tissue-culture-treated microtiter plates.