TABLE 2.

Definitions employed in this study

Result	EB MIC (μg/ml)	Expression of MDR efflux pump genes	Efflux phenotype (% efflux)
True positive	≥25	Increased expression of ≥1 gene	≥20
False positive	≥25	No increase	<20
True negative	≤12.5	No increase	<20
False negative	≤12.5	Increased expression of ≥1 gene	≥20