title: Detection of mutations in parC in quinolone-resistant clinical isolates of Escherichia coli.
abstract: The gene parC encodes the A subunit of topoisomerase IV of Escherichia coli. Mutations in the parC region analogous to those in the quinolone resistance-determining region of gyrA were investigated in 27 clinical isolates of E. coli for which ciprofloxacin MICs were 0.0007 to 128 micrograms/ml. Of 15 isolates for which ciprofloxacin MICs were > or = 1 microgram/ml, 8 showed a change in the serine residue at position 80 (Ser-80), 4 showed a change in Glu-84, and 3 showed changes in both amino acids. No mutations were detected in 12 clinical isolates for which ciprofloxacin MICs were < or = 0.25 micrograms/ml. These findings suggest that ParC from E. coli may be another target for quinolones and that mutations at residues Ser-80 and Glu-84 may contribute to decreased fluoroquinolone susceptibility.
authors.affiliation: Department of Microbiology, University of Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Vila
authors.forename: J
authors.initials: J
authors.lastname: Ruiz
authors.forename: P
authors.initials: P
authors.lastname: Goñi
authors.forename: M T
authors.initials: MT
authors.lastname: De Anta
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D000951:Antigens, Neoplasm; D001483:Base Sequence; D002939:Ciprofloxacin / Q000494:pharmacology*; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004268:DNA-Binding Proteins; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D007527:Isoenzymes / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D017386:Sequence Homology, Amino Acid
chemical_list: D000890:Anti-Infective Agents; D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D002939:Ciprofloxacin; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II