DNA heterogeneity of Staphylococcus aureus strains evaluated by SmaI and SgrAI pulsed-field gel electrophoresis in patients with impetigo

To our knowledge, no studies have previously been carried out on the hetero geneity and intrafamily colonization of impetigo Staphylococcus aureus stra ins obtained by powerful discriminating methods such as pulsed-field gel el ectrophoresis (PFGE). To explore this topic, macrorestriction patterns of S . aureus strains were analyzed after SmaI and SgrAI digestion. The two enzy mes provided superimposable results. A total of ninety-seven S. aureus stra ins was found in the 26 families whose lesions and nasal and pharyngeal sam ples were examined. There were 39 strains which were different by PFGE, and of these, 24 were found in the lesions. Although 85% of impetigo patients showed nasal colonization and 58% showed pharyngeal colonization, only 54% of the patients had the same PFGE strain in the lesion and in the nose, and 35% in the lesion and the pharynx. In half of the 26 families, at least on e member (mother, father, or relative) presented a S. aureus strain identic al, by PFGE, to strains isolated in patients' lesions. Nineteen percent of mothers, 15% of fathers, and 19% of the other relatives presented nasal col onization with strains identical to those isolated in the children's lesion s. Lesional strains showed higher antimicrobial resistance than nonlesional isolates. (C) 2000 Editions scientifiques et medicales Elsevier SAS.