TABLE 3.

Evaluation of accuracies of automated systems for susceptibility testing of 100 P. aeruginosa strains against β-lactam antimicrobial agents

Antimicrobial and error typea	Error rate (%)
	MicroScan WalkAway	VITEK 2	VITEK
Aztreonam
Very major	0	0	2
Major	0	1	2
Minor	28	31	28
Cefepime
Very major	0	0	0
Major	3	1	0
Minor	32	18	26
Ceftazidime
Very major	0	1	2
Major	0	1	0
Minor	13	9	11
Imipenem
Very major	0	1	0
Major	2	2	2
Minor	10	8	11
Piperacillin-tazobactam
Very major	19	27	21
Major	1	0	0

^aError rates were calculated based on the consensus result among the broth microdilution (frozen dry-form panels), agar dilution, and disk diffusion methods.