Effect of low-level resistance on subsequent enrichment of fluoroquinolone-resistant Streptococcus pneumoniae in rabbits.

Etienne, Manuel; Croisier, Delphine; Charles, Pierre-Emmanuel; Lequeu, Catherine; Piroth, Lionel; Portier, Henri; Drlica, Karl; Chavanet, Pascal · J Infect Dis · 2004

other · Level V

Where this comes from

Abstract

We measured the effect of low-level fluoroquinolone resistance in Streptococcus pneumoniae on the development of high-level resistance within the context of the mutant selection window. Rabbits infected with S. pneumoniae were treated with ciprofloxacin or moxifloxacin concentrations that simulated pharmacokinetics in treated humans; bacteria obtained from lungs were examined for fluoroquinolone susceptibility. Ciprofloxacin enriched resistant mutants from a wild-type strain; moxifloxacin did not. However, moxifloxacin enriched resistant mutants from a parC mutant; the drug concentration at the top of the selection window was determined. A parC resistance mutation facilitates the enrichment of high-level resistance, as was predicted by in vitro measurements.

Medical subject headings