title: Bacterial epidemiology of osteoarticular infections in a referent center: 10-year study.
abstract: BACKGROUND
  Management of osteoarticular infections combines surgical treatment with antibiotic therapy. For some teams the immediate postoperative regimen requires at least partly wide-spectrum probabilistic treatment while waiting for the microbiological results. This protocol exposes the patient to the selection of resistant bacteria and the hospital unit to a modification of its bacterial ecology. The objective of this study was to retrospectively describe the microbial epidemiology of the Traumatology and Orthopaedics Department of the Lille University Hospital over 10 years (2002-2011).
  
  
  METHODS
  The bacterial species isolated in culture of osteoarticular samples were listed, after removing any duplicates. The antibiotics retained for follow-up were those used in treatment of these infections as well as those recognized as markers of resistance. For Gram-positive species, the antibiotics considered were methicillin, rifampicin, fluoroquinolones, glycopeptides, and linezolid; for the Gram-negative species, cefotaxime, cefepime, imipenem, and fluoroquinolones were considered.
  
  
  RESULTS
  Of the 5006 strains isolated between 2002 and 2011, Gram-positive cocci accounted for more than 71%; Staphylococcus aureus 27%, and coagulase-negative staphylococci (CoNS) 54%. Contrary to S. aureus, resistance to methicillin, fluoroquinolones, and teicoplanin significantly increased in CoNS, reaching 44%, 34%, and 22%, respectively, of the strains in 2011. The proportion of streptococcal and enterococcal infections remained stable, a mean 7.4% and 5.3%, respectively, per year. Enterobacteria (12.5% of the isolates) were producers of extended-spectrum beta-lactamase in 7.8% of the cases. Pseudomonas aeruginosa was involved in 3.6% of the infections, and 12% of the strains remained resistant to ceftazidime. Propionibacterium acnes accounted for 5.8% of the bacteria isolated and showed few antibiotic resistance problems.
  
  
  CONCLUSIONS
  Stability in the distribution and the susceptibility of different bacterial species was noted over this 10-year period. Although the evolution of S. aureus resistance was favourable, the resistance of CoNS specially to methicillin and glycopeptides increased.
  
  
  METHODS
  Level IV. Retrospective cohort study.
authors.affiliation: Institut de microbiologie, CHU de Lille, 59037 Lille, France; Université de Lille Nord de France, Lille, France.
authors.forename: M
authors.initials: M
authors.lastname: Titécat
authors.forename: E
authors.initials: E
authors.lastname: Senneville
authors.forename: F
authors.initials: F
authors.lastname: Wallet
authors.forename: H
authors.initials: H
authors.lastname: Dezèque
authors.forename: H
authors.initials: H
authors.lastname: Migaud
authors.forename: R-J
authors.initials: RJ
authors.lastname: Courcol
authors.forename: C
authors.initials: C
authors.lastname: Loïez
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001170:Arthritis, Infectious / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*; D001424:Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005602:France / Q000453:epidemiology; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D008297:Male; D008826:Microbial Sensitivity Tests; D010000:Osteitis / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotics; Bacterial resistance; Epidemiology; Osteoarticular infections; Referent center for osteoarticular infection