title: Correlations between Income inequality and antimicrobial resistance.
abstract: OBJECTIVE
  The aim of this study is to investigate if correlations exist between income inequality and antimicrobial resistance. This study's hypothesis is that income inequality at the national level is positively correlated with antimicrobial resistance within developed countries.
  
  
  METHODS
  Income inequality data were obtained from the Standardized World Income Inequality Database. Antimicrobial resistance data were obtained from the European antimicrobial Resistance Surveillance Network and outpatient antimicrobial consumption data, measured by Defined daily Doses per 1000 inhabitants per day, from the European Surveillance of antimicrobial Consumption group. Spearman's correlation coefficient (r) defined strengths of correlations of: > 0.8 as strong, > 0.5 as moderate and > 0.2 as weak. Confidence intervals and p values were defined for all r values. Correlations were calculated for the time period 2003-10, for 15 European countries.
  
  
  RESULTS
  Income inequality and antimicrobial resistance correlations which were moderate or strong, with 95% confidence intervals > 0, included the following. Enterococcus faecalis resistance to aminopenicillins, vancomycin and high level gentamicin was moderately associated with income inequality (r= ≥0.54 for all three antimicrobials). Escherichia coli resistance to aminoglycosides, aminopenicillins, third generation cephalosporins and fluoroquinolones was moderately-strongly associated with income inequality (r= ≥0.7 for all four antimicrobials). Klebsiella pneumoniae resistance to third generation cephalosporins, aminoglycosides and fluoroquinolones was moderately associated with income inequality (r= ≥0.5 for all three antimicrobials). Staphylococcus aureus methicillin resistance and income inequality were strongly associated (r=0.87).
  
  
  CONCLUSIONS
  As income inequality increases in European countries so do the rates of antimicrobial resistance for bacteria including E. faecalis, E. coli, K. pneumoniae and S. aureus. Further studies are needed to confirm these findings outside Europe and investigate the processes that could causally link income inequality and antimicrobial resistance.
authors.affiliation: Department of Microbiology, Leeds Teaching Hospitals National Health Service Trust, Leeds, West Yorkshire, United Kingdom. kirbyandrew@doctors.org.uk
authors.forename: Andrew
authors.initials: A
authors.lastname: Kirby
authors.forename: Annie
authors.initials: A
authors.lastname: Herbert
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000187:drug effects; D019049:Developed Countries / Q000706:statistics & numerical data; D004352:Drug Resistance, Microbial; D005060:Europe; D006801:Humans; D062486:Public Health Surveillance; D012959:Socioeconomic Factors
chemical_list: D000900:Anti-Bacterial Agents