MULTIDRUG-RESISTANT IBERIAN EPIDEMIC CLONE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS ENDEMIC IN A HOSPITAL IN NORTHERN PORTUGAL

Forty-two methicillin-resistant Staphylococcus aureus (MRSA) isolates collected during 1992-1995 at a hospital in the north of Portugal were characterized by a variety of genomic fingerprints, Hybridization of ClaI and SmaI restriction digests with the mecA- and Tn554-specific DN A probes was used to identify polymorphs and determine their localizat ion in chromosomal DNA preparations, and pulsed-field gel electrophore tic analysis of SmaI digests was used to determine chromosomal backgro unds. A major clone (and its variants) carrying the mecA polymorph I, Tn554 type E in the PFGE background of pattern A, accounted for 85% of all MRSA tested in 1999-1993 and 66% in 1994-1995. This clone is clos ely related to the epidemic Iberian clone that was associated with out breaks in Spain during 1989-1993 and was endemic in 1992-1993 in two h ospitals in Lisbon (Portugal).