ASSOCIATION OF MUTATIONS IN GRLA AND GYRA TOPOISOMERASE GENES WITH RESISTANCE TO CIPROFLOXACIN IN EPIDEMIC AND SPORADIC ISOLATES OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS

The types of topoisomerase alterations in genomically diverse epidemic and sporadic strains of methicillin-and fluoroquinolone-resistant Sta phylococcus aureus isolated from European hospitals between 1984 and 1 994 were characterized. Convergent dual mutations in gyrA (codon 83, 8 4, or 88) and grlA (codon 79 and/or 80) were found in all strains exhi biting high-level resistance to ciprofloxacin (MIG, 16 to greater than or equal to 128 mu g/ml). In some epidemic strains, the resistant phe notype and genotype appeared in the 1990s and persisted thereafter.