Bactericidal activity of garenoxacin tested by kill-curve methodology against wild type and QRDR mutant strains of Streptococcus pneumoniae.
Kill-curve bactericidal assays over 24 hours were determined for garenoxacin, a novel des-F(6) quinolone, and levofloxacin at achievable serum drug concentrations ranging from 2 to 8 microg/mL. Tested strains included 4 wild type and 2 target quinolone resistance-determining region (QRDR) mutant Streptococcus pneumoniae. Garenoxacin was 16-fold to 32-fold more active than levofloxacin, and mutant strains (3 QRDR sites) had garenoxacin minimum inhibitory concentration (MIC) values at 1 microg/mL (levofloxacin MIC >32 microg/mL, resistant), but equal to the levofloxacin potency against wild type strains. Garenoxacin killed mutant pneumococci with comparable rapidity, as did levofloxacin versus strains without target alterations. Garenoxacin appears to be a widely usable and highly active agent against S. pneumoniae resistant to other quinolones such as levofloxacin.
Anderegg
Tamara R
TR
The JONES Group/JMI Laboratories, North Liberty, IA, USA.
Jones
Ronald N
RN
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D024841:Fluoroquinolones / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D009154:Mutation; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics; D013997:Time Factors
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; C419689:garenoxacin