FIG. 3.

(A) PFGE profiles for eight pairs of MRSA and MR-MSSA strains isolated from the same patients (lane pairs 1 to 8, respectively). Except for the samples from patient 5, the restriction profiles for both isolates originating from each patient are similar but not identical: the MSSA strain loses a DNA fragment at about the 200-kb band, which carries SCCmec in ST8. (B) Four pairs of related MR-MSSA and MRSA isolates after PFGE, Southern blotting, and hybridization with a digoxigenin-labeled mecA probe. The probe hybridizes with the 200-kb band in MRSA but not with bands of smaller sizes in MR-MSSA. Asterisks, lanes with MR-MSSA strains.