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In vitro activity of new quinolones against Clostridium difficile
R Alonso1, T Peláez, M J González-Abad
1Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario 'Gregorio Marañón', C/Doctor Esquerdo 46, 28007 Madrid, Spain. ralonso@microb.net
The Journal of Antimicrobial Chemotherapy
|February 7, 2001
Summary
New fluoroquinolones show limited effectiveness against Clostridium difficile in vitro. Resistance rates were high, suggesting none are reliable therapeutic options for C. difficile infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Clostridium difficile is a significant cause of antibiotic-associated diarrhea.
- Fluoroquinolones are a class of antibiotics with broad-spectrum activity.
- Emerging resistance patterns necessitate evaluation of antibiotic efficacy.
Purpose of the Study:
- To assess the in vitro activity of five fluoroquinolones against Clostridium difficile.
- To determine the minimum inhibitory concentration (MIC90) for each drug.
- To evaluate resistance rates of C. difficile to these fluoroquinolones.
Main Methods:
- In vitro susceptibility testing was performed.
- Minimum inhibitory concentration (MIC90) values were determined for ofloxacin, levofloxacin, grepafloxacin, trovafloxacin, and ciprofloxacin.
- Resistance percentages were calculated for each agent.
Main Results:
- MIC90 values ranged from 8 mg/L (trovafloxacin) to 128 mg/L (ofloxacin, levofloxacin).
- Thirty percent of C. difficile isolates were resistant to trovafloxacin.
- Resistance rates for ofloxacin, levofloxacin, grepafloxacin, and ciprofloxacin were considerably higher than for trovafloxacin.
Conclusions:
- None of the evaluated fluoroquinolones demonstrated reliable therapeutic potential against C. difficile in vitro.
- High resistance rates suggest limited clinical utility for these agents.
- Further investigation is needed to determine if new fluoroquinolones can induce C. difficile-associated diarrhea.