Characteristics of the prototype MRSA strains used in this study.

Abbreviations: neg., negative; pos., positive; WT, wild-type.Notes:a)Clonal types as defined by MLST sequence type (ST) and SCCmec type.b)neg. – negative (due to IS1272 insertion); WT – wild-type sequence (N315);*- mutated non-functional mecI at Gln68 (CAA→TAA);c)IS::ΔmecR1 – mecR1 with no C-terminal sensor domain (due to IS1272 insertion); ΔmecR1 – 160 bp deletion in the C-terminal inducer domain.d)The production of β-lactamase was assayed in induced and no induced cultures (see text for details). All strains positive for β-lactamase were inducible.e)MIC as determined by E-test strips.f)Parental strains transformed with a high copy number plasmid containing the wild-type mecI coding region (pGC2-mecIWT).