title: Prolongation of antibiotic prophylaxis after clean and clean-contaminated surgery and surgical site infection.
abstract: OBJECTIVE
  Several guidelines have recommended that antibiotic prophylaxis (AMP) should be given only at premedication, except in selected cases. Conversely, in clinical practice, AMP is often unnecessarily prolonged after the surgical procedure. In this observational study, we evaluated the risk of surgical site infection (SSI) associated with the prolongation of AMP after clean and clean-contaminated surgery.
  
  
  METHODS
  All consecutive patients who underwent a surgical procedure were eligible. AMP was always administered before the surgical incision. Prolongation of AMP for the first 24 hours was allowed only in presence of at least one risk factor for SSI: an ASA score >2 or surgical procedure longer than the specific cutoff (as indicated by the NNIS--the National Nosocomial Infections Surveillance System). SSIs were evaluated during the hospital stay and after hospital discharge.
  
  
  RESULTS
  Three hundred fifty-eight patients were enrolled; 19 (5.3%) and 17 (6.5%) patients developed respectively intra-hospital and post hospital discharge SSIs. AMP prolongation for 24 hours in patients with at least one risk factor did not reduce the risk for intra-hospital SSI (OR 1.102; 95% CI: 0.336-3.612; P=0.873), while it increased the risk in patients without risk factors (OR: 8.99; 95% CI: 1.46-55.4; P=0.018). AMP longer than 24 hours raised the risk for intra-hospital and post hospital discharge SSI, regardless of the presence of risk factors (OR: 3.39; 95% CI 1.11-10.35; P=0.032 and OR: 5.39; 95% CI: 1.64-17.75; P=0.006, respectively.)
  
  
  CONCLUSIONS
  Postoperative AMP prolongation should be avoided.
authors.affiliation: Department of General Resuscitation, Institute of Anesthesia and Resuscitation University of Milan, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli and Regina Elena, Milan, Italy. sergiodechiara@policlinico.mi.it
authors.forename: S
authors.initials: S
authors.lastname: De Chiara
authors.forename: D
authors.initials: D
authors.lastname: Chiumello
authors.forename: R
authors.initials: R
authors.lastname: Nicolini
authors.forename: M
authors.initials: M
authors.lastname: Vigorelli
authors.forename: B
authors.initials: B
authors.lastname: Cesana
authors.forename: N
authors.initials: N
authors.lastname: Bottino
authors.forename: G
authors.initials: G
authors.lastname: Giurati
authors.forename: M L
authors.initials: ML
authors.lastname: Caspani
authors.forename: L
authors.initials: L
authors.lastname: Gattinoni
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge; D011184:Postoperative Period; D011446:Prospective Studies; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents