title: Effect of individual- and group-level antibiotic exposure on MRSA isolation: a multilevel analysis.
abstract: OBJECTIVE
  To observe the relative role of individual and group-level antimicrobial selective pressure on subsequent methicillin-resistant Staphylococcus aureus (MRSA) isolation in a university hospital.
  
  
  METHODS
  For this purpose, 18 596 patients were included in a retrospective statistical analysis, applying multilevel modelling with discrete time intervals at the lowest level. Individual-level and hospital group variables on antimicrobial exposure and MRSA colonization pressure were collected from computerized databases.
  
  
  RESULTS
  The simultaneous hospital group- and individual-level analysis showed individual exposure to fluoroquinolones and collective exposure to penicillins to be associated with MRSA isolation after adjustment for colonization pressure and other potential confounders.
  
  
  CONCLUSIONS
  These results support efforts to reduce prescriptions of selected antimicrobial drug classes such as fluoroquinolones and show the added value of multilevel analysis for research on the adverse outcomes of antibiotic prescribing.
authors.affiliation: Service d'Hygiène Hospitalière et d'Epidémiologie moléculaire, Centre Hospitalier Universitaire Jean Minjoz, 25030 Besançon, France.
authors.forename: Arno
authors.initials: A
authors.lastname: Muller
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mauny
authors.forename: Daniel
authors.initials: D
authors.lastname: Talon
authors.forename: Peter T
authors.initials: PT
authors.lastname: Donnan
authors.forename: Stephan
authors.initials: S
authors.lastname: Harbarth
authors.forename: Xavier
authors.initials: X
authors.lastname: Bertrand
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology / Q000627:therapeutic use; D006785:Hospitals, University; D006801:Humans; D016015:Logistic Models; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D008954:Models, Biological; D010406:Penicillins / Q000494:pharmacology / Q000627:therapeutic use; D010818:Practice Patterns, Physicians'; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D010406:Penicillins