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Effects of subinhibitory concentrations of moxifloxacin in an in-vitro dynamic model

F Maggiolo1, R Capra, A Bartoli

  • 1Department of Infectious Diseases, General Hospital, Busto Arsizio, Italy. malinfbusto@tin.it

Journal of Chemotherapy (Florence, Italy)
|May 2, 2000
PubMed

Insights

Moxifloxacin exhibits prolonged postantibiotic effects (PAE) and sub-inhibitory effects (SME), with postantibiotic sub-MIC effects (PASME) also observed. These findings support the potential for once-daily dosing of moxifloxacin.

Area of Science:

  • Pharmacology
  • Microbiology
  • Infectious Diseases

Background:

  • The postantibiotic effect (PAE), sub-MIC effect (SME), and postantibiotic sub-MIC effect (PASME) are crucial pharmacokinetic/pharmacodynamic parameters influencing antibiotic efficacy.
  • Understanding these effects for fluoroquinolones like moxifloxacin is vital for optimizing dosing regimens.

Purpose of the Study:

  • To investigate the PAE, SME, and PASME of moxifloxacin against key bacterial pathogens using an in-vitro dynamic model.
  • To evaluate the impact of sub-inhibitory concentrations on moxifloxacin's postantibiotic activity.

Main Methods:

  • An in-vitro dynamic model simulating in-vivo elimination kinetics was employed.
  • Bacterial strains (Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae) were exposed to 5x MIC moxifloxacin for 1.5 hours to induce PAE.
  • Cultures were then incubated with or without 0.5x MIC moxifloxacin to assess SME and PASME.

Main Results:

  • Both PASME (mean 11:17 hours) and SME (mean 9:23 hours) were significantly longer than PAE (mean 1:31 hours).
  • PASMEs were consistently longer than SMEs, though not always statistically significant.
  • Moxifloxacin sub-MICs demonstrated a primary prevalent effect within the PAE.

Conclusions:

  • Moxifloxacin exhibits substantial and prolonged postantibiotic and sub-inhibitory effects.
  • The observed extended effects suggest that moxifloxacin may be suitable for once-daily dosing regimens.
  • Further investigation into the clinical implications of these findings is warranted.

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