Relationship of carbapenem restriction in 22 university teaching hospitals to carbapenem use and carbapenem-resistant Pseudomonas aeruginosa

Antimicrob Agents Chemother. 2009 May;53(5):1983-6. doi: 10.1128/AAC.01535-08. Epub 2009 Mar 9.


Many hospital antimicrobial stewardship programs restrict the availability of selected drugs by requiring prior approval. Carbapenems may be among the restricted drugs, but it is unclear if hospitals that restrict availability actually use fewer carbapenems than hospitals that do not restrict use. Nor is it clear if restriction is related to resistance. We evaluated the relationship between carbapenem restriction and the volume of carbapenem use and both the incidence rate and proportion of carbapenem-resistant Pseudomonas aeruginosa isolates from 2002 through 2006 in a retrospective, longitudinal, multicenter analysis among a consortium of academic health centers. Carbapenem use was measured from billing records as days of therapy per 1,000 patient days. Hospital antibiograms were used to determine both the incidence rate and proportion of carbapenem-resistant P. aeruginosa isolates. A survey inquired about restriction policies for antibiotics, including carbapenems. General linear mixed models were used to examine study outcomes. Among 22 hospitals with sufficient data for analysis, overall carbapenem use increased significantly over the 5 years of study (P < 0.0001), although overall carbapenem resistance in P. aeruginosa did not change. Hospitals that restricted carbapenems (n = 8; 36%) used significantly fewer carbapenems (P = 0.04) and reported lower incidence rates of carbapenem-resistant P. aeruginosa (P = 0.01) for all study years. Fluoroquinolone use was a potential confounder of these relationships, but hospitals that restricted carbapenems actually used fewer fluoroquinolones than those that did not. Restriction of carbapenems is associated with both lower use and lower incidence rates of carbapenem resistance in P. aeruginosa.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Carbapenems / pharmacology
  • Carbapenems / therapeutic use*
  • Drug Resistance, Bacterial*
  • Hospitals, Teaching / statistics & numerical data
  • Hospitals, University / statistics & numerical data
  • Humans
  • Incidence
  • Longitudinal Studies
  • Microbial Sensitivity Tests
  • Middle Aged
  • Practice Patterns, Physicians' / statistics & numerical data
  • Pseudomonas Infections / drug therapy
  • Pseudomonas Infections / epidemiology*
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / drug effects*


  • Anti-Bacterial Agents
  • Carbapenems