Broad-host-range gyrase A gene probe

Antimicrob Agents Chemother. 1990 Oct;34(10):1889-94. doi: 10.1128/aac.34.10.1889.


The Escherichia coli gyrase A gene was cloned in the broad-host-range cosmid vector pLA2917. The resulting plasmid, pNJR3-2, conferred quinolone susceptibility on a gyrA mutant of E. coli. To analyze the expression of this E. coli gene in Pseudomonas aeruginosa, pNJR3-2 or pLA2917 was mobilized via conjugation into P. aeruginosa PAO2 and several well-characterized quinolone-resistant mutants of this strain. The vector pLA2917 did not significantly affect the quinolone susceptibilities of any of the P. aeruginosa strains. However, pNJR3-2 conferred wild-type quinolone susceptibility on P. aeruginosa cfxA (gyrA) mutants and intermediate quinolone susceptibility on cfxA-cfxB double mutants of P. aeruginosa. The quinolone susceptibility of P. aeruginosa PAO2 gyrA+ was unaffected by pNJR3-2. Also, pNJR3-2 had no significant effect on P. aeruginosa cfxB (permeability) mutants. These results demonstrate that the DNA gyrase A gene from E. coli is expressed in P. aeruginosa and confers dominant susceptibility on gyrA mutants. Thus, pNJR3-2 can be used to detect the quinolone resistance mutations that occur in the gyrase A gene of this organism. pNJR3-2 also appears to discriminate between mutations in gyrA and mutations which alter permeability. This gyrase A probe was used successfully in the analysis of quinolone resistance in clinical isolates of P. aeruginosa.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • DNA Topoisomerases, Type II / genetics*
  • DNA Topoisomerases, Type II / isolation & purification
  • Escherichia coli / drug effects
  • Escherichia coli / genetics*
  • Gene Expression Regulation, Bacterial*
  • Gene Expression Regulation, Enzymologic*
  • Genes, Bacterial*
  • Genetic Vectors
  • Genotype
  • Microbial Sensitivity Tests
  • Phenotype
  • Plasmids
  • Pseudomonas aeruginosa / drug effects
  • Pseudomonas aeruginosa / genetics*


  • Anti-Bacterial Agents
  • DNA Topoisomerases, Type II