Inhibition of R-plasmid transfer in Escherichia coli by 4-quinolones.
Inhibition of transfer of four conjugative R plasmids by ciprofloxacin, enoxacin, norfloxacin, ofloxacin, and pipemidic acid was investigated in an Escherichia coli mating system. The absolute concentrations needed for inhibition of conjugation varied from 0.12 microgram/ml for ciprofloxacin to 16 micrograms/ml for pipemidic acid, but the relationship to the MICs for the parent strains was identical for all substrates. Concentrations for a 90% reduction of transconjugants were in the range of one to six times the MIC for the parent strains, which also had lethal effects on donors and recipients. A similar effect on conjugation was found with chloramphenicol. These observations question the specificity of transfer inhibition by quinolones and cast doubt on the clinical importance of such an effect.
Weisser
J
J
Wiedemann
B
B
D003227:Conjugation, Genetic / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D008826:Microbial Sensitivity Tests; D011804:Quinolines / Q000494:pharmacology*; D011815:R Factors
D011804:Quinolines