The aim of this study is to prospectively investigate the additional diagnostic value of broad range PCR targeting the 16 ribosomal DNA in diagnosis and management of patients with infective endocarditis who are candidate for surgicaltherapy;

Study protocol is divided into four different phases:screening, pre-operative clinical assessment (T-1), cardiac surgery (T0) and follow-up period (T4 eT90).

During the screening phase, patients will be assessed to determine whether they met the study inclusion/exclusion criteria. After signing the informed consent, patients will go through a preoperative clinical evaluation (T-1). The following assessments are carried out the day before surgery: recording patient's generality, present antibiotic therapy and possible results of blood cultures performed prior to recruitment; - Twelve-lead ECG; - chest X-ray - transthoracic echocardiogram (TTE); -. three pairs of blood cultures from three different blood sampling sites. In cases of complicated endocarditis, the presence and location of septic embolisms is recorded (using Total body CT scan imaging), signs of heart failure evaluated and operability criteria are assessed. On the day of cardiac surgery (T0), main intraoperative data (valve findings, type of prosthesis, surgery time, cardiopulmonary bypass time and aortic cross clamping time) will be gathered; the excised valve was sent partly to the microbiology laboratory for culture and molecular tests and partly to the pathology Laboratory.

After cardiac surgery, patients continued to be monitored for a follow up at four (T4) and 90 (T90) days after surgery. During the follow-up period, information was collected on the patient's clinical status (vital parameters) and the antibiotic treatment performed. The same blood tests performed at T-1 are repeated at T4 and T90. All this data was recorded on a dedicated database.

Inclusion Criteria:

1. patients older than 18 years, with diagnosis of IE on a native or prosthetic valve and with a surgical indication for heart valve replacement using extracorporeal circulation (CPB).
2. patients who have signed informed consent to the partecipation of the study

Exclusion criteria:

1. patients younger than 18 years
2. Failure to sign consent for personal data processing and/or study participation
3. Participation in other experimental studies
4. Patients who did not complete the examinations under study (culture test on blood and excised valve, molecular tests)