title: European Surveillance of Antimicrobial Consumption (ESAC): outpatient antibiotic use in Europe (1997-2009).
abstract: OBJECTIVE
  To describe total outpatient systemic antibiotic use in Europe from 1997 to 2009 and to analyse statistically trends of total use and composition of use over time.
  
  
  METHODS
  For the period 1997-2009, data on outpatient use of systemic antibiotics aggregated at the level of the active substance were collected and expressed in defined daily doses (WHO, version 2011) and packages per 1000 inhabitants per day (DID and PID, respectively). Outpatient antibiotic (ATC J01) use in DID in the 33 European countries able to deliver valid data was analysed using longitudinal and compositional data analyses.
  
  
  RESULTS
  Total outpatient antibiotic use in 2009 varied by a factor of 3.8 between the countries with the highest (38.6 DID in Greece) and lowest (10.2 DID in Romania) use. For Europe, a significant increase was found in total outpatient antibiotic use, as well as a significant seasonal variation, which decreased over time from 1997 to 2009. Relative use of penicillins and quinolones significantly increased over time with respect to sulphonamides and trimethoprim, and relative use of quinolones increased with respect to macrolide/lincosamide/streptogramin as well. More detailed analyses of these major antibiotic subgroups will be described in separate papers.
  
  
  CONCLUSIONS
  Outpatient antibiotic use in Europe measured as DID has increased since 1997, whereas seasonal variation has decreased over time. European Surveillance of Antimicrobial Consumption (ESAC) data on outpatient antibiotic use in Europe enable countries to audit their antibiotic use. Complemented by longitudinal and compositional data analyses, these data provide a tool for assessing public health strategies aimed at reducing antibiotic resistance and optimizing antibiotic prescribing.
authors.affiliation: Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerp, Belgium. niels.adriaenssens@ua.ac.be
authors.forename: Niels
authors.initials: N
authors.lastname: Adriaenssens
authors.forename: Samuel
authors.initials: S
authors.lastname: Coenen
authors.forename: Ann
authors.initials: A
authors.lastname: Versporten
authors.forename: Arno
authors.initials: A
authors.lastname: Muller
authors.forename: Girma
authors.initials: G
authors.lastname: Minalu
authors.forename: Christel
authors.initials: C
authors.lastname: Faes
authors.forename: Vanessa
authors.initials: V
authors.lastname: Vankerckhoven
authors.forename: Marc
authors.initials: M
authors.lastname: Aerts
authors.forename: Niel
authors.initials: N
authors.lastname: Hens
authors.forename: Geert
authors.initials: G
authors.lastname: Molenberghs
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
mesh_terms: D000553:Ambulatory Care; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001424:Bacterial Infections / Q000188:drug therapy; D004363:Drug Utilization / Q000706:statistics & numerical data* / Q000639:trends; D005060:Europe; D006801:Humans; D010045:Outpatients / Q000706:statistics & numerical data*; D010406:Penicillins / Q000627:therapeutic use; D017891:Pharmacoepidemiology / Q000379:methods; D015363:Quinolones / Q000627:therapeutic use; D012621:Seasons; D013223:Statistics as Topic / Q000379:methods; D014295:Trimethoprim / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D015363:Quinolones; D014295:Trimethoprim