Background: Infectious endocarditis of fungal origin is rare but of high mortality. The agents involved are mainly opportunists of the genus Candida and Aspergillus; however other fungi can also cause this disease.
Clinical Case: The case of a woman who suffered unknown origin intermittent fever for several months; and in who, by blood culture (after lysis-centrifugation) and molecular biology techniques, Histoplasma capsulatum was identified as etiological agent. The histological study showed abundant intracellular yeasts and hyphae in intracardiac vegetations.
Conclusion: This first report of infectious endocarditis by H. capsulatum in Mexico highlights the importance of using in addition to manual blood culture (lysis-centrifugation) and histological study, faster and more sensitive diagnostic methods, such as serology and molecular biology, to confirm or rule out an invasive fungal infection and identify the agents.