title: No need for broad-spectrum empirical antibiotic coverage after surgical drainage of orthopaedic implant infections.
abstract: OBJECTIVE
  Empirical broad-spectrum antibiotic treatment for orthopaedic implant infections after surgical lavage is common practice while awaiting microbiological results, but lacks evidence.
  
  
  METHODS
  This was a single-centre cohort study from 1996 to 2010 with a follow-up of two years.
  
  
  RESULTS
  We retrieved 342 implant infections and followed them up for a median of 3.5 years (61 recurred, 18%). Infected implants were arthroplasties (n = 186), different plates, nails or other osteosyntheses. The main pathogens were S. aureus (163, 49 methicillin-resistant) and coagulase-negative staphylococci (60, 45 methicillin-resistant). Median duration of empirical antibiotic coverage after surgical drainage was three days before switching to targeted therapy. Vancomycin was the most frequent initial empirical agent (147), followed by intravenous co-amoxiclav (44). Most empirical antibiotic regimens (269, 79%) proved sensitive to the causative pathogen, but were too broad in 111 episodes (32%). Cephalosporins and penicillins were used only in 44 and ten cases, respectively, although they would have covered 59% of causative pathogens identified later. Multivariate Cox regression analysis showed that neither susceptible antibiotic coverage (compared to non-susceptible; hazard ratio 0.7, 95% confidence interval 0.4-1.2) nor broad-spectrum use (hazard ratio 1.1, 0.8-1.5) changed remission rates.
  
  
  CONCLUSIONS
  Provided that surgical drainage is performed, broad-spectrum antibiotic coverage does not enhance remission of orthopaedic implant infections during the first three days. If empirical agents are prescribed from the first day of infection, narrow-spectrum penicillins or cephalosporins can be considered to avoid unnecessary broad-spectrum antibiotic use.
authors.affiliation: Orthopedic Surgery Service, Geneva University Hospitals & Faculty of Medicine, University of Geneva, 4, Rue Gabrielle Perret-Gentil, 1211, Geneva 14, Switzerland.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schindler
authors.forename: Axel
authors.initials: A
authors.lastname: Gamulin
authors.forename: Wilson
authors.initials: W
authors.lastname: Belaieff
authors.forename: Maruschka
authors.initials: M
authors.lastname: Francescato
authors.forename: Alexis
authors.initials: A
authors.lastname: Bonvin
authors.forename: Véronique
authors.initials: V
authors.lastname: Graf
authors.forename: Pierre
authors.initials: P
authors.lastname: Hoffmeyer
authors.forename: Blaise
authors.initials: B
authors.lastname: Wyssa
authors.forename: Ilker
authors.initials: I
authors.lastname: Uçkay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D002511:Cephalosporins / Q000627:therapeutic use; D015331:Cohort Studies; D004322:Drainage / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000627:therapeutic use; D016459:Prosthesis-Related Infections / Q000517:prevention & control* / Q000628:therapy*; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014640:Vancomycin / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins; D014640:Vancomycin