Southern blot of HindIII-digested plasmid DNA from selected Mupr S. aureus isolates hybridized with an ileS2 probe. Lane 1, MRSA isolate 1 (Hi-Mupr); lane 2, MRSA isolate 4 (low-level Mupr); lane 3, MRSA isolate 5 (Hi-Mupr); lane 4, MRSA isolate 8 (Hi-Mupr); lane 5, MSSA isolate 13 (Hi-Mupr).