Disease relevance of gyrA

• Some mutations in gyrA, known to confer high-level resistance to quinolones or CcdB, confer low-level resistance or hypersensitivity to albicidin in Escherichia coli [1].
• In vivo selection of reduced enrofloxacin susceptibility in Ornithobacterium rhinotracheale and its resistance-related mutations in gyrA [2].
• A nucleotide mutation associated with fluoroquinolone resistance observed in gyrA of in vitro obtained Rhodococcus equi mutants [3].
• RESULTS: The Salmonella Infantis isolate exhibited the Asp87-->Tyr87 mutation in gyrA, but no resistance-mediating mutations in the other target genes [4].

High impact information on gyrA

• In the Deltafis strain, both topA and gyrA/B genes were found to be upregulated [5].
• We characterized gyrA and parC mutations and organic solvent tolerance (OST) [6].
• With S. aureus, the dimer selected spontaneous resistant gyrA mutants, whereas ciprofloxacin selected a parC mutant [7].
• Only three isolates (3%) were resistant to nalidixic acid (reduced susceptibility to ciprofloxacin), with a single mutation in the gyrA gene [8].
• Typhimurium representative single-step mutants showed reduced susceptibilities associated with point mutations in the QRDR of the gyrA gene or efflux pump system [9].

Chemical compound and disease context of gyrA

• OBJECTIVES: To evaluate the mutant prevention concentrations (MPCs) of ciprofloxacin for two susceptible and one first-step gyrA resistant mutant Escherichia coli strains in an in vitro kinetic model and to identify the pharmacodynamic index that best predicts prevention of resistance emergence [10].

Biological context of gyrA

• The molecular background for the fluoroquinolone-resistance was investigated and point mutations in gyrA and parC leading to amino-acid substitutions in quinolone-resistance determining regions of GyrA and ParC were demonstrated [11].

Associations of gyrA with chemical compounds

• The objective of this study was to analyse an array of ciprofloxacin and norfloxacin derivatives in order to determine those with good activity against bacteria that already present fluoroquinolone resistance associated with mutations in the gyrA and/or parC genes [12].

Other interactions of gyrA

• In this study, the quinolone resistance-determining region (QRDR) in gyrA and gyrB of in vitro fluoroquinolone-resistant Rhodococcus equi mutants was sequenced [3].

References