Activity of gemifloxacin against penicillin- and ciprofloxacin-resistant Streptococcus pneumoniae displaying topoisomerase- and efflux-mediated resistance mechanisms.
Nine penicillin-resistant Streptococcus pneumoniae clinical isolates from Northern Ireland, resistant to ciprofloxacin (MICs, 2 to 64 microg/ml) through topoisomerase- and/or reserpine-sensitive efflux mechanisms, were highly susceptible to gemifloxacin (MICs, 0.03 to 0. 12 microg/ml). Two strains (requiring a ciprofloxacin MIC of 64 microg/ml) carried known quinolone resistance mutations in parC, parE, and gyrB, resulting in S79F, D435V, and E474K changes, respectively. Thus, gemifloxacin is active against clinical strains exhibiting altered topoisomerase and efflux phenotypes.
Heaton
V J
VJ
Molecular Genetics Group, Department of Biochemistry, St. George's Hospital Medical School, University of London, London SW17 ORE, United Kingdom.
Goldsmith
C E
CE
Ambler
J E
JE
Fisher
L M
LM
D000890:Anti-Infective Agents / Q000378:metabolism / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000378:metabolism / Q000494:pharmacology*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D000077735:Gemifloxacin; D006801:Humans; D009287:Naphthyridines / Q000378:metabolism / Q000494:pharmacology*; D009660:Northern Ireland; D010403:Penicillin Resistance; D010641:Phenotype; D011008:Pneumococcal Infections / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D009287:Naphthyridines; D002939:Ciprofloxacin; D004264:DNA Topoisomerases, Type I; D000077735:Gemifloxacin