Table 1. Comparison of colistin MICs determined by Sensititre and the CLSI broth macrodilution reference method.

Sensititre MIC (μg/mL)		No. isolates with initial/final colistin reference MIC (μg/mL)a
	No. isolates	≥0.5	1	2	4	8	>8
<0.25	74	67/69	2	2b/3b	1b,c/0	2c,d/0	-
0.5	4	4	-	-	-	-	-
1	-	-	-	-	-	-	-
2	4	-	-	-	2c/3c	1b,c/1b,c	1b,c/0
4	2	-	-	-	-	2b	-
>4	22	-	-	-	-	1	21
Total	106	71/73	2	2/3	3	6/4	22/21

^aDetermined by CLSI broth macrodilution method.

^bMinor errors if a susceptible breakpoint of ≤1 μg/mL, an intermediate breakpoint of 2–4 μg/mL, and a resistant breakpoint of >8 μg/mL were applied.

^cVery major errors if EUCAST breakpoints (≤2 μg/mL, susceptible; ≥4 μg/mL, resistant) were applied.

^dVery major errors if a susceptible breakpoint of ≤1 μg/mL, an intermediate breakpoint of 2–4 μg/mL, and a resistant breakpoint of ≥8 μg/mL were applied.