Effects of subinhibitory concentrations of moxifloxacin in an in-vitro dynamic model.
The postantibiotic effect (PAE), sub-MIC effect (SME) and postantibiotic sub-MIC effect (PASME) of moxifloxacin were investigated in an in-vitro dynamic model reproducing in-vivo elimination kinetics of the antibiotic. The PAE was induced by exposing strains of Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli and Klebsiella pneumoniae to 5 x MIC of the antibiotic for 1.5 hours. After induction, cultures were washed to eliminate the antibiotic and resuspended into the dynamic model either in the presence or absence of a subinhibitory concentration of the antibacterial agent of 0.5 x MIC. Unexposed controls were treated similarly. PASMEs were constantly longer than corresponding SMEs, but differences between them were not statistically significant. Both PASMEs (mean 11:17 hours, range from 8:17 to 14:57) and SMEs (mean 9:23 hours, range from 6:03 to 12:34) had an initial bactericidal effect and were significantly longer than PAEs (mean 1:31 hours, range from 0:21 to 2:14). The primary effect of moxifloxacin sub-MICs appears to be prevalent in PAE. The possibility of once-daily dosing of the drug is strengthened.
Maggiolo
F
F
Department of Infectious Diseases, General Hospital, Busto Arsizio, Italy. malinfbusto@tin.it
Capra
R
R
Bartoli
A
A
Bottura
P
P
Migliorino
M
M
Suter
F
F
D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001372:Aza Compounds; D001419:Bacteria / Q000145:classification / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D024841:Fluoroquinolones; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000379:methods; D000077266:Moxifloxacin; D011804:Quinolines; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects
D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D000077266:Moxifloxacin