JAC Advance Access published online on August 13, 2003
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkg380
© 2003 by The British Society for Antimicrobial Chemotherapy
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Brief report
1 College of Pharmacy, Washington State University Spokane,
310 North Riverpoint Boulevard, P.O. Box 1495, Spokane, WA 99210-1495,
USA
* Corresponding author. E-mail: garrism{at}wsu.edu.
Received 14 March 2003
; revised 17 June 2003
; accepted 17 June 2003
Objectives: Levofloxacin
has good coverage against both Gram-positive and Gram-negative pathogens. Recent
reports demonstrate enhanced activity associated with a higher 750
mg dosage of levofloxacin. The objective of this study was to comparatively
evaluate the activity of common regimens of levofloxacin (500 mg)
and ciprofloxacin (500 mg), and a higher 750 mg levofloxacin regimen
against penicillin susceptible and non-susceptible strains of S. pneumoniae. Materials and methods: An in vitro pharmacodynamic
modelling apparatus (PDMA) characterized specific bacterial kill
profiles for simulated regimens of levofloxacin and ciprofloxacin
against four strains of S. pneumoniae. Total log
reduction, time for 3-log reduction and AUC/MIC were determined. Results: Ciprofloxacin was less effective than
the levofloxacin regimens against all four study isolates. Ciprofloxacin
produced 3-log reduction in only one isolate compared with all four
isolates with the levofloxacin regimens. Bacterial regrowth did
not occur over 12 h with levofloxacin; however, three of four isolates
demonstrated bacterial regrowth with ciprofloxacin. None of the
isolates were cleared from the PDMA by ciprofloxacin. The 500 mg
levofloxacin regimen cleared two of four isolates and the 750 mg
dose of levofloxacin cleared all study isolates. Respective AUC/MIC
values for levofloxacin (500 and 750 mg) and ciprofloxacin were
44-89, 63-126 and Conclusions: Both levofloxacin regimens were
more effective than ciprofloxacin against the study isolates tested.
The 750 mg levofloxacin regimen generated more favourable bacterial
killing compared with the 500 mg levofloxacin regimen. In
addition to using the 750 mg levofloxacin dose for nosocomial infections, this
dose may also prove useful for the management of resistant pneumococcal
infections.
Keywords: levofloxacin, resistant S. pneumoniae,
quinolones, pharmacodynamics
Comparative antimicrobial activity of levofloxacin
and ciprofloxacin against Streptococcus pneumoniae
13,
which correlated well with bacterial kill data.![]()
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