FIG 2.

Correlation of MexY protein abundance with mexY gene expression level and aminoglycoside resistance. (A) MexY (113-kDa) protein levels were detected by Western blot analysis using a polyclonal anti-MexY antibody in 53 clinical isolates. The results of tobramycin susceptibility testing as reported previously (30) are shown (MIC of tobramycin [MIC TOB] in micrograms per milliliter). mexY expression (also reported in reference 30) is indicated as fold-change gene expression compared to the PA14 reference strain. (B) The PA14 ΔmexZ or ΔmexRZ mutant strains were used as positive controls on each blotting membrane. Arrows indicate strains with mexY overexpression on the mRNA level but missing or only faint MexY protein band. M, PageRuler prestained protein ladder. Black bars indicate borders of single Western blotting membranes.