Topoisomerase mutations in trovafloxacin-resistant Staphylococcus aureus

Abstract

A total of 201 Staphylococcus aureus isolates were surveyed for susceptibility to ciprofloxacin and trovafloxacin. Of 66 methicillin- resistant isolates, 89% were ciprofloxacin resistant and 6% were also trovafloxacin resistant. Trovafloxacin-resistant strains had unusual patterns of quinoline resistance mutations in DNA topoisomerase genes, including two mutations in the A subunit (encoded by grlA) of topoisomerase IV.