Intercontinental spread of a multidrug-resistant methicillin-resistant Staphylococcus aureus clone

Two hundred ten methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered between 1990 and 1997 from three Portuguese hospitals located in Lisbon and Oporto were analyzed by molecular fingerprinting techniques. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis documented the abrupt appearance and extensive intrahospital spread of the Brazilian epidemic MRSA clone in the 1995 samples of each one of the three hospitals analyzed-suggesting the intercontinental transfer of this strain from Brazil to Portugal. The appearance of this clone may challenge the dominance of another highly epidemic imported clone-the Iberian MRSA, currently the most widely spread MRSA clone in Portuguese hospitals.