Evaluation of an agar-gradient minimum-inhibitory-concentration method (the Etest) as a rapid and direct measure of antimicrobial susceptibility in Gram-negative bacteraemia

BACKGROUND

The selection of appropriate antibiotics to treat Gram-negative bacteraemia may be life-saving. Rapid methods of antimicrobial susceptibility testing have sought to guide early antibiotic selection and usage. We sought to evaluate whether a combination of chromogenic agar and six Etest gradient diffusion strips could be used to provide a clinically useful, direct rapid antimicrobial susceptibility test result following 4 hours of incubation.