title: A systematic review and meta-analysis of the effects of antibiotic consumption on antibiotic resistance.
abstract: BACKGROUND
  Greater use of antibiotics during the past 50 years has exerted selective pressure on susceptible bacteria and may have favoured the survival of resistant strains. Existing information on antibiotic resistance patterns from pathogens circulating among community-based patients is substantially less than from hospitalized patients on whom guidelines are often based. We therefore chose to assess the relationship between the antibiotic resistance pattern of bacteria circulating in the community and the consumption of antibiotics in the community.
  
  
  METHODS
  Both gray literature and published scientific literature in English and other European languages was examined. Multiple regression analysis was used to analyse whether studies found a positive relationship between antibiotic consumption and resistance. A subsequent meta-analysis and meta-regression was conducted for studies for which a common effect size measure (odds ratio) could be calculated.
  
  
  RESULTS
  Electronic searches identified 974 studies but only 243 studies were considered eligible for inclusion by the two independent reviewers who extracted the data. A binomial test revealed a positive relationship between antibiotic consumption and resistance (p < .001) but multiple regression modelling did not produce any significant predictors of study outcome. The meta-analysis generated a significant pooled odds ratio of 2.3 (95% confidence interval 2.2 to 2.5) with a meta-regression producing several significant predictors (F(10,77) = 5.82, p < .01). Countries in southern Europe produced a stronger link between consumption and resistance than other regions.
  
  
  CONCLUSIONS
  Using a large set of studies we found that antibiotic consumption is associated with the development of antibiotic resistance. A subsequent meta-analysis, with a subsample of the studies, generated several significant predictors. Countries in southern Europe produced a stronger link between consumption and resistance than other regions so efforts at reducing antibiotic consumption may need to be strengthened in this area. Increased consumption of antibiotics may not only produce greater resistance at the individual patient level but may also produce greater resistance at the community, country, and regional levels, which can harm individual patients.
authors.affiliation: Division of Primary Care, University of Nottingham, University Park, Nottingham NG7 2RD, UK. brian.bell@nottingham.ac.uk.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Bell
authors.forename: Francois
authors.initials: F
authors.lastname: Schellevis
authors.forename: Ellen
authors.initials: E
authors.lastname: Stobberingh
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
authors.forename: Mike
authors.initials: M
authors.lastname: Pringle
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004352:Drug Resistance, Microbial; D005060:Europe; D006801:Humans; D016017:Odds Ratio
chemical_list: D000900:Anti-Bacterial Agents