All patients participating in the study will undergo standard diagnostic process. Conventional/standard diagnostic and therapeutic process will consist of: medical interview, physical examination, laboratory tests, blood cultures (3 sets, 1 hour apart, repeated after 24 hours and -if applicable - with fever peak above 38°C); imaging studies (echocardiography: transthoracic, and if there are no contraindications transesophageal, in case of negative or equivocal result repeated after 7-10 days, or in series if necessary, computed tomography scan for pulmonary embolism if indicated); if there are abnormalities in other systems, decisions concerning further diagnostics will be made by the physician in charge.