Fig. 1

Study design. ^aDialysis or creatinine clearance ≤30 mL/min. ^bInfectious diseases that required antibiotic therapy in the previous 2 weeks. ^cPatients with solid or hematologic tumours, as well as patients underwent chemotherapy or radiation therapy in the previous 6 months. ^dPreoperative stay in the intensive care unit (ICU) for more than 24 h. ^ePatients were considered at high risk of developing surgical site infections in case of: chronic liver disease (classified as Child-Pugh class B and C); insulin-dependent diabetes; body mass index <17 or >40 kg/m²; steroid or other immunosuppressive drug use; chronic obstructive pulmonary disease; and extracardiac arteriopathy (i.e., claudication, carotid occlusion or >50% stenosis, amputation for arterial disease and previous or planned intervention on the abdominal aorta, limb arteries or carotids). ^fViolation of antimicrobial prophylaxis timing protocol