Open AccessPharmacodynamics of Moxifloxacin against Streptococcus pyogenes in an In Vitro Kinetic Model
Author(s) -
Inga Odenholt,
Elisabeth Löwdin,
Ingegerd Gustafsson,
Otto Cars
Publication year - 2002
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.46.6.2046-2048.2002
Subject(s) - moxifloxacin , streptococcus pyogenes , pharmacodynamics , erythromycin , microbiology and biotechnology , pharmacokinetics , streptococcus pneumoniae , antibiotics , biology , antibacterial agent , in vitro , pharmacology , bacteria , staphylococcus aureus , biochemistry , genetics
The aim of the present study was to investigate the pharmacodynamics of moxifloxacin against strains of Streptococcus pyogenes with different susceptibilities to erythromycin by using an in vitro kinetic model simulating human pharmacokinetics of moxifloxacin at oral doses of 400 and 200 mg, respectively. When the different strains of S. pyogenes were exposed to the higher dose, the number of bacteria was reduced below the detection limit after 12 h and no regrowth was noted during the following 12 h. At the lower dose there was regrowth of the strains with constitutive and inducible erythromycin resistance of the MLS(B) phenotype. Replication assays of the regrowing bacteria indicated that the failure of moxifloxacin to kill the MLS(B) strains at the lower dose was likely caused by the emergence of preexisting resistant subpopulations. Thus, the present study indicates that the presently used 400-mg dose seems to have an advantage over the lower dose in that the risk for selection of resistant subpopulations is minimized.