S-aureus PFGE patterns of lesional or non lesional strains from patients with impetigo: Association of individual bands with lesional or non lesionalareas

PFGE has been extensively used to obtain a reliable intra-species different iation, although this technique has not been completely standardized. In th is study, PFGE was applied to analyze in detail the patterns of 19 lesional S. aureus strains isolated from patients with impetigo, compared with 15 n on-lesional strains isolated from nasal or pharyngeal swabs of the same pat ients. The strain DNA was extracted and processed as previously reported, u sing the strictest protocol to limit the variations between different analy tical sets. To obtain maximum sensitivity and comparability, the electropho resis patterns were analyzed by an automated and computerized reader (GelDo c1000). The DNA fragments (range 12-15 bands) obtained for each individual strain were then divided into 39 zones including from 1 to 4 bands for a to tal of at least 91 possible different gel positions. The positivity for each zone (and/or the positivity for the individual band s contained) was associated with the lesional/non-lesional origin and with the face localization of the strains.