GEOGRAPHIC SPREAD OF EPIDEMIC MULTIRESISTANT STAPHYLOCOCCUS-AUREUS CLONE IN BRAZIL

Staphylococcus aureus isolates from five large teaching hospitals and one medium-size community hospital located in geographically distant p arts of Brazil, in the south and southeast (Rio de Janeiro, Niteroi, S ao Paulo, Porto Alegre) and in the north (Manaus), were tested for the ir antibiotic resistance patterns and genetic backgrounds, Eighty-five of the 152 isolates were identified as methicillin-resistant S. aureu s (MRSA) by using a combination of an agar dilution screen and a mecA gene-specific DNA probe, All MRSA isolates were resistant to penicilli n, erythromycin, gentamicin, oxacillin, and cephalothin, and the major ity of isolates (74%) were also resistant to chloramphenicol, sulfamet hoxazole-trimethoprim, ciprofloxacin, and clindamycin as well and were susceptible only to vancomycin, Isolates obtained from hospitals in S ao Paulo, Rio de Janeiro, Niteroi, and Porto Alegre (1,600 km from one another) and Manaus (3,700 km from Rio de Janeiro) were examined by a variety of molecular fingerprinting techniques: the nature of the mec A polymorph and Tn554 attachment sites and restriction fragment length polymorphism of genomic DNAs after SmaI restriction and separation of the digested DNA by pulsed-field gel electrophoresis, The overwhelmin g majority of the isolates shared a common pulsed-field gel electropho resis pattern and carried mecA polymorph III in combination with Tn554 pattern B, indicating the presence of a single, epidemic MRSA clone s pread over large geographic distances of Brazil.