Comparative study of the effect of thiabendazole and fungizone on Histoplasma capsulatum in macrophages
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Abstract:
The antifungal properties of Fungizone (amphotericin B intravenous solution) and thiabendazole on Histoplasma capsulatum within guinea pig macrophages were compared using the staining method and a newly developed plating method to determine the viability of intracellular H. capsulatum. The two methods were compared to determine the effectiveness of Fungizone and thiabendazole on H. capsulatum within macrophages. Fungizone was fungicidal for intracellular H. capsulatum, killing 99.9% of the yeasts at a concentration of 0.5 microgram/ml. There was some indication that non-viable intracellular yeasts were stained which could result in misinterpretation of the effectiveness of Fungizone using the staining method unless the yeasts are very closely examined for staining abnormalities. There was a good correlation between the two methods to demonstrate suppression of the multiplication of intracellular H. capsulatum in macrophages treated with 50 microgram/ml of thiabendazole. Thiabendazole was lethal for some intracellular H. capsulatum.
Insights
Fungizone (amphotericin B) effectively killed 99.9% of intracellular Histoplasma capsulatum yeasts. Thiabendazole suppressed yeast multiplication and was lethal to some intracellular yeasts, with methods showing good correlation.
Area of Science:
- Medical Mycology
- Pharmacology
- Infectious Diseases
Background:
- Histoplasma capsulatum is an intracellular fungal pathogen causing histoplasmosis.
- Effective treatment of intracellular H. capsulatum requires agents that penetrate host cells.
- Evaluating antifungal efficacy against intracellular pathogens presents methodological challenges.
Purpose of the Study:
- To compare the antifungal activity of Fungizone (amphotericin B) and thiabendazole against intracellular Histoplasma capsulatum.
- To evaluate the reliability of a novel plating method versus a staining method for assessing intracellular fungal viability.
- To determine the fungicidal and fungistatic effects of these agents on H. capsulatum within macrophages.
Main Methods:
- Guinea pig macrophages infected with H. capsulatum were treated with varying concentrations of Fungizone and thiabendazole.
- Intracellular fungal viability was assessed using a traditional staining method and a newly developed plating method.
- Comparison of the two methods was performed to validate their effectiveness in determining drug efficacy.
Main Results:
- Fungizone (amphotericin B) demonstrated potent fungicidal activity, eliminating 99.9% of intracellular H. capsulatum at 0.5 µg/ml.
- The staining method showed potential for misinterpretation due to staining of non-viable yeasts, necessitating careful examination.
- Thiabendazole at 50 µg/ml suppressed the multiplication of intracellular H. capsulatum, exhibiting lethal effects on some yeasts.
Conclusions:
- Fungizone (amphotericin B) is highly effective and fungicidal against intracellular Histoplasma capsulatum.
- The novel plating method shows good correlation with the staining method for assessing intracellular fungal suppression.
- Thiabendazole demonstrates fungistatic and some fungicidal activity against intracellular H. capsulatum within macrophages.