Improved susceptibility of Gram-negative bacteria in an intensive care unit following implementation of a computerized antibiotic decision support system

J Antimicrob Chemother. 2010 May;65(5):1062-9. doi: 10.1093/jac/dkq058. Epub 2010 Mar 9.


Objectives: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / therapeutic use*
  • Australia
  • Decision Support Systems, Clinical*
  • Female
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacterial Infections / drug therapy*
  • Health Services Research*
  • Hospitals, Teaching
  • Humans
  • Intensive Care Units
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Prospective Studies


  • Anti-Bacterial Agents