title: Improved susceptibility of Gram-negative bacteria in an intensive care unit following implementation of a computerized antibiotic decision support system.
abstract: OBJECTIVE
  Emergence of multiresistant Gram-negative organisms in intensive care units (ICUs) throughout the world is a concerning problem. Therefore we undertook a study to follow the resistance patterns of the most common clinically isolated Gram-negative organisms within our ICU following an antibiotic stewardship intervention to evaluate whether a reduction in broad-spectrum antibiotics improves local antibiotic resistance patterns.
  
  
  METHODS
  This prospective study was conducted over a 7 year period within an ICU at a tertiary teaching hospital in Melbourne, Australia. All clinically isolated Gram-negative organisms were identified and extracted from the hospital pathology system. Three monthly antibiograms were created. The pre-interventional period occurred between January 2000 and June 2002 (10 quarters) and the post-interventional period was defined from July 2002 to December 2006 (18 quarters). Segmented linear regression was used to analyse for a difference in the rates of change in susceptibility.
  
  
  RESULTS
  A total of 2838 Gram-negative organisms were isolated from clinical sites from ICU patients during the study period. There was significant improvement in susceptibility of Pseudomonas to imipenem 18.3%/year [95% confidence interval (CI): 4.9-31.6; P = 0.009] and gentamicin 11.6%/year (95% CI: 1.8-21.5; P = 0.02) compared with the pre-intervention trend. Significant changes in the rates of gentamicin and ciprofloxacin susceptibility were also observed in the inducible Enterobacteriaceae group although these were less clinically significant.
  
  
  CONCLUSIONS
  This study demonstrates improved antibiotic susceptibility of ICU Gram-negative isolates including Pseudomonas following an intervention aimed at reducing broad-spectrum antibiotics.
authors.affiliation: Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, VIC 3050, Australia. M.Yong@alfred.org.au
authors.forename: M K
authors.initials: MK
authors.lastname: Yong
authors.forename: K L
authors.initials: KL
authors.lastname: Buising
authors.forename: A C
authors.initials: AC
authors.lastname: Cheng
authors.forename: K A
authors.initials: KA
authors.lastname: Thursky
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001315:Australia; D020000:Decision Support Systems, Clinical; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy*; D006302:Health Services Research; D006784:Hospitals, Teaching; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D000900:Anti-Bacterial Agents