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Published on: February 14, 2011
In vitro effect of sulfamethoxazole-trimethoprim against Histoplasma capsulatum var. capsulatum
Raimunda Sâmia Nogueira Brilhante1, Maria Auxiliadora Bezerra Fechine, Rossana de Aguiar Cordeiro
1Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil. brilhante@ufc.br
Abstract:
This study evaluated the in vitro effect of sulfamethoxazole-trimethoprim against Histoplasma capsulatum var. capsulatum isolated from HIV-positive patients. The drugs were tested by microdilution testing in accordance with the CLSI guidelines. All of the strains were inhibited by sulfamethoxazole-trimethoprim, with MIC ranges of 0.039 (sulfamethoxazole)/0.0078 (trimethoprim) mg/ml to 0.625/0.125 mg/ml for mycelial forms and 0.0025/0.0005 to 0.02/0.004 mg/ml for yeast-like forms. However, in vivo studies are necessary to evaluate the significance of these results.
Insights
Sulfamethoxazole-trimethoprim effectively inhibited all tested Histoplasma capsulatum strains from HIV patients in vitro. Further in vivo research is needed to confirm these findings for clinical application.
Area of Science:
- Mycology
- Infectious Diseases
- Pharmacology
Background:
- Histoplasma capsulatum is an opportunistic fungal pathogen.
- HIV-positive patients are at increased risk for disseminated histoplasmosis.
- Limited in vitro data exists on the efficacy of sulfamethoxazole-trimethoprim against Histoplasma capsulatum.
Purpose of the Study:
- To evaluate the in vitro antifungal activity of sulfamethoxazole-trimethoprim against Histoplasma capsulatum var. capsulatum.
- To determine the minimum inhibitory concentrations (MICs) of sulfamethoxazole-trimethoprim for different morphological forms of the fungus.
- To assess the potential of sulfamethoxazole-trimethoprim as a therapeutic agent for histoplasmosis in HIV-positive individuals.
Main Methods:
- Microdilution testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines.
- Sulfamethoxazole-trimethoprim was tested against Histoplasma capsulatum var. capsulatum strains isolated from HIV-positive patients.
- Minimum inhibitory concentrations (MICs) were determined for both mycelial and yeast-like forms of the fungus.
Main Results:
- Sulfamethoxazole-trimethoprim demonstrated inhibitory activity against all tested strains of Histoplasma capsulatum.
- MIC ranges for mycelial forms were 0.039/0.0078 to 0.625/0.125 mg/ml.
- MIC ranges for yeast-like forms were significantly lower, ranging from 0.0025/0.0005 to 0.02/0.004 mg/ml.
Conclusions:
- Sulfamethoxazole-trimethoprim exhibits potent in vitro activity against Histoplasma capsulatum.
- The drug is more effective against the yeast-like (parasitic) form compared to the mycelial (environmental) form.
- In vivo studies are warranted to establish the clinical relevance and therapeutic efficacy of sulfamethoxazole-trimethoprim for treating histoplasmosis, particularly in immunocompromised patients.
