We report the case of a 40-year-old male patient with no prior personal pathological history, who had a prolonged febrile syndrome without being associated with other important clinical features. He was diagnosed with subacute bacterial endocarditis in the native mitral valve by an atypical pathogen: Hafnia Alvei . After an exhaustive review of the bibliography of the last 20 years corresponding to the Cuban medical journals, we conclude that we are facing the first clinical case of this type published in Cuba.
