title: Salmonella typhimurium gyrA mutations associated with fluoroquinolone resistance.
abstract: Spontaneous quinolone-resistant mutants obtained from Salmonella typhimurium Su694 were screened for mutations by direct DNA sequencing of an amplified PCR gyrA fragment. Substitutions Ser-83-->Phe (Ser83Phe), Ser83Tyr, Asp87Tyr, and Asp87Asn and double mutation Ala67Pro-Gly81Ser, which resulted in decreased sensitivities to ciprofloxacin, enoxacin, pefloxacin, norfloxacin, ofloxacin, and nalidixic acid, were found. The levels of resistance to quinolones for each mutant were determined.
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II