Figure 3

Effect of SA1665 deletion on oxacillin resistance. A, Growth of MRSA strains and their SA1665 deletion mutants, containing empty plasmid vector pAW17 or pBUS1, and trans complemented mutants, containing pME26 or pME27, was compared on plates containing appropriate oxacillin gradients, as indicated. Plates were supplemented with either kanamycin (25 μg/ml) or tetracycline (5 μg/ml) to ensure plasmid maintainence. B, Representative population analysis profiles of MRSA strains CHE482, ZH37, ZH44, and ZH73 and their corresponding mutants. Wildtype strains are indicated by squares and mutants by triangles. x- and y-axis show the oxacillin concentrations (μg/ml) and the cfu/ml, respectively. Oxacillin concentrations used were two-fold dilutions ranging from 0.1–256 μg/ml for strains CHE482 and ZH37 and 1–1024 μg/ml for strains ZH44 and ZH73. C, Growth curves of wildtype strains (solid lines, closed symbols) and their corresponding SA1665 mutants (dashed lines, open symbols); CHE482 (diamonds), ZH37 (triangles), ZH44 (circles), ZH73 (squares).