TABLE 1.

S. aureus strains used in this study

Strain	Relevant feature of the strain	Reference
Mu50	Reduced susceptibility to vancomycin (MIC, 8 μg/ml)	11
Mu3	Reduced susceptibility to vancomycin (heterogeneousa)	11
Mu50ω	Reduced susceptibility to vancomycin (heterogeneousa)	This study
N315	Susceptible to vancomycin, pre-MRSA	7
H1	Susceptible to vancomycin, MRSA	11
FDA209P	Susceptible to vancomycin, MSSAb type strain	11
BB255	Equivalent to NCTC8325, MSSA	11
BB270	NCTC8325 transduced with mec determinant	5
BB589	femC mutant derived from BB270	5

^aContains subpopulation of cells for which the MIC is 8 μg/ml or greater. 

^bMSSA, methicillin-susceptible S. aureus.