In vitro activities of gemifloxacin versus five quinolones and two macrolides against 271 Spanish isolates of Legionella pneumophila: influence of charcoal on susceptibility test results.
The MICs at which 90% of isolates are inhibited for gemifloxacin, trovafloxacin, and grepafloxacin were low (</=0.01 microg/ml) for 271 Legionella isolates when they were determined by the broth microdilution method but increased (>/=6 dilutions) when they were determined by the agar dilution method. This was due to the charcoal in the agar dilution medium, as shown by the progressive decrease in the MICs when the charcoal concentrations decreased. As free drug is the active fraction, charcoal binding should be considered.
García
M T
MT
Spanish National Reference Laboratory, Instituto de Salud Carlos III, Carretera. Majadahonda a Pozuelo, 28220 Majadahonda, Spain.
Pelaz
C
C
Giménez
M J
MJ
Aguilar
L
L
D042462:4-Quinolones; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002606:Charcoal / Q000494:pharmacology*; D004347:Drug Interactions; D024841:Fluoroquinolones; D000077735:Gemifloxacin; D006801:Humans; D016952:Legionella pneumophila / Q000187:drug effects* / Q000302:isolation & purification; D018942:Macrolides; D008826:Microbial Sensitivity Tests; D009287:Naphthyridines / Q000494:pharmacology*; D013030:Spain
D042462:4-Quinolones; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D018942:Macrolides; D009287:Naphthyridines; D002606:Charcoal; D000077735:Gemifloxacin