title: Antimicrobial use and incidence of multidrug-resistant Pseudomonas aeruginosa in a teaching hospital: an ecological approach.
abstract: BACKGROUND
  Multidrug-resistant Pseudomonas aeruginosa is a major threat in healthcare settings. The use of antimicrobials can influence the incidence of resistant strains by direct and indirect mechanisms. The latter can be addressed by ecological studies.
  
  
  METHODS
  Our group attempted to analyze the relation between the use of antipseudomonal drugs and the incidence of MDR-PA among 18 units from a 400-bed teaching hospital. The study had a retrospective, ecological design, comprising data from 2004 and 2005. Data on the use of four antimicrobials (amikacin, ciprofloxacin, ceftazidime and imipenem) were tested for correlation with the incidence of MDR-PA (defined as isolates resistant to the four antimicrobials of interest) in clinical cultures. Univariate and multivariate linear regression analyses were performed.
  
  
  RESULTS
  Significant correlations were determined between use and resistance for all antimicrobials in the univariate analysis: amikacin (standardized correlation coefficient = 0.73, p = 0.001); ciprofloxacin (0.71, p = 0.001); ceftazidime (0.61, p = 0.007) and imipenem (0.87, p < 0.001). In multivariate analysis, only imipenem (0.67, p = 0.01) was independently related to the incidence of multidrug-resistant strains.
  
  
  CONCLUSIONS
  These findings share similarities with those reported in individual-based observational studies, with possible implications for infection control.
authors.affiliation: Department of Tropical Diseases, Botucatu School of Medicine, São Paulo State University, Botucatu, SP, Brazil.
authors.forename: Mariana Tresoldi das
authors.initials: MT
authors.lastname: Neves
authors.forename: Mariana Eliza Pinto de
authors.initials: ME
authors.lastname: Lorenzo
authors.forename: Ricardo Augusto Monteiro Barros
authors.initials: RA
authors.lastname: Almeida
authors.forename: Carlos Magno Castelo Branco
authors.initials: CM
authors.lastname: Fortaleza
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D006784:Hospitals, Teaching; D006801:Humans; D015994:Incidence; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012189:Retrospective Studies
chemical_list: D000900:Anti-Bacterial Agents