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Published on: February 14, 2018
In vitro susceptibility testing of Dientamoeba fragilis.
N Nagata1, D Marriott, J Harkness
1Division of Microbiology, SydPath, St. Vincent’s Hospital, Darlinghurst, Australia.
Antimicrobial Agents and Chemotherapy
|October 26, 2011
Summary
This study evaluated Dientamoeba fragilis susceptibility to common antiparasitic drugs. 5-nitroimidazole derivatives like ornidazole and ronidazole showed the highest in vitro activity against this gastrointestinal parasite.
Area of Science:
- Medical Parasitology
- Antimicrobial Susceptibility Testing
- Molecular Biology
Background:
- Dientamoeba fragilis is a common trichomonad linked to human gastrointestinal illness.
- Despite frequent infections, limited research exists on D. fragilis antimicrobial susceptibility.
- Understanding drug efficacy is crucial for treating D. fragilis infections.
Purpose of the Study:
- To assess the in vitro susceptibility of Dientamoeba fragilis clinical isolates to a broad spectrum of antiparasitic agents.
- To identify the most effective treatments for D. fragilis infections based on minimum lethal concentrations.
Main Methods:
- Four clinical strains of D. fragilis (genotype 1) were tested.
- Antiparasitic agents were evaluated at concentrations from 2 μg/ml to 500 μg/ml.
- Susceptibility was determined by counting D. fragilis trophozoites in dixenic culture.
Main Results:
- 5-nitroimidazole derivatives (ornidazole, ronidazole, tinidazole, metronidazole, secnidazole) demonstrated significant in vitro activity.
- Ornidazole and ronidazole exhibited minimum lethal concentrations of 8–16 μg/ml.
- Other agents like tetracycline, furazolidone, iodoquinol, paromomycin, and diloxanide furoate showed lower efficacy.
Conclusions:
- This study provides the first comprehensive susceptibility profiles for clinical D. fragilis isolates against multiple treatments.
- 5-nitroimidazole derivatives are the most potent compounds in vitro against D. fragilis.
- Findings guide the selection of effective therapies for D. fragilis infections.
