Table 2: Antimicrobial susceptibility profile of Escherichia coli isolates recovered from patients in Canadian hospitals as part of the CANWARD study

Antimicrobial	All isolates (n = 5571)			Colistin-resistant subset (n = 12)
Antimicrobial	MIC₅₀, µg/mL	MIC₉₀, µg/mL	% susceptible	MIC₅₀, µg/mL	MIC₉₀, µg/mL	% susceptible
Amoxicillin-clavulanate	4	16	85.8 (4783/5571)	4	8	91.7 (11/12)
Cefazolin	2	32	71.2 (3967/5571)	2	8	75.0 (9/12)
Ceftazidime	≤ 0.5	1	94.0 (5238/5571)	≤ 0.25	0.5	100.0 (12/12)
Ceftriaxone	≤ 0.25	0.5	91.7 (5109/5571)	≤ 0.25	≤ 0.25	100.0 (12/12)
Ciprofloxacin	≤ 0.06	> 16	76.7 (4274/5571)	≤ 0.06	> 16	75.0 (9/12)
Colistin	0.25	0.5	99.8 (5559/5571)	4	8	0 (0/12)
Gentamicin	≤ 0.5	2	90.5 (5043/5571)	≤ 0.5	32	75.0 (9/12)
Meropenem	≤ 0.06	≤ 0.06	100.0 (5570/5571)	≤ 0.03	≤ 0.03	100.0 (12/12)
Piperacillin-tazobactam	2	4	97.5 (5434/5571)	≤ 1	4	100.0 (12/12)
Trimethoprim-sulfamethoxazole	≤ 0.12	> 8	72.6 (4047/5571)	≤ 0.12	> 8	83.3 (10/12)