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Experimental chemotherapy of histoplasmosis in nude mice
Abstract:
Nude (nu/nu) mice were infected with Histoplasma capsulatum and treated with varying doses of 3 drug regimens: oral ambruticin, intraperitoneal amphotericin B, and amphotericin B plus oral rifampin. Therapy with amphotericin B alone was the most effective regimen. High-dose ambruticin (50 mg/kg of body weight every 8 hours) led to significantly prolonged survival compared to that of untreated control animals, but no long-term cures. Addition of rifampin produced no benefit and might actually have decreased the efficacy of amphotericin B; this combination may be deleterious in a setting of immunodeficiency.
Insights
Amphotericin B monotherapy proved most effective for Histoplasma capsulatum infections in mice. High-dose ambruticin prolonged survival, but combination therapy with rifampin showed no benefit and potential harm in immunodeficient models.
Area of Science:
- Mycology
- Infectious Diseases
- Pharmacology
Background:
- Histoplasma capsulatum is an opportunistic fungal pathogen causing histoplasmosis.
- Immunocompromised individuals, such as nude mice, are particularly susceptible to disseminated fungal infections.
- Effective antifungal therapies are crucial for managing severe mycoses.
Purpose of the Study:
- To evaluate the efficacy of different drug regimens for treating Histoplasma capsulatum infection in an immunocompromised mouse model.
- To compare ambruticin, amphotericin B, and a combination of amphotericin B plus rifampin.
- To assess the impact of these treatments on survival and potential adverse effects.
Main Methods:
- Nude (nu/nu) mice were infected with Histoplasma capsulatum.
- Mice received varying doses of oral ambruticin, intraperitoneal amphotericin B, or amphotericin B plus oral rifampin.
- Survival rates and clinical outcomes were monitored throughout the study.
Main Results:
- Amphotericin B monotherapy was the most effective treatment, leading to the best outcomes.
- High-dose ambruticin (50 mg/kg every 8 hours) significantly prolonged survival but did not achieve long-term cures.
- The addition of rifampin to amphotericin B provided no benefit and potentially reduced amphotericin B's efficacy, suggesting a deleterious effect in immunodeficient hosts.
Conclusions:
- Amphotericin B remains a highly effective agent for Histoplasma capsulatum infections.
- Ambruticin shows some survival benefit but lacks curative potential in this model.
- Combination therapy with amphotericin B and rifampin may be detrimental in immunocompromised patients with histoplasmosis.