title: Health and economic outcomes of antibiotic resistance in Pseudomonas aeruginosa.
abstract: BACKGROUND
  Antimicrobial resistance is an increasing problem.
  
  
  OBJECTIVE
  To examine the clinical and economic impact of antibiotic resistance in Pseudomonas aeruginosa.
  
  
  METHODS
  In-hospital mortality, secondary bacteremia, length of stay, and hospital charges were examined in a cohort of 489 inpatients with positive clinical cultures for P aeruginosa. One hundred forty-four had a resistant baseline P aeruginosa isolate and 30 had resistance emerge during follow-up. Multivariable and survival analytic methods were used to adjust for confounding and effects of time.
  
  
  RESULTS
  The overall in-hospital mortality rate was 7.6%, 7.7% in patients with a resistant isolate at baseline (relative risk [RR], 1.3; 95% confidence interval [CI], 0.6-2.8) and 27% in patients in whom resistance emerged (RR, 3.0; 95% CI, 1.2-7.8). Secondary bacteremia developed in 1.4% of patients in whom resistance did not emerge and in 14% of those in whom resistance emerged (RR, 9.0; 95% CI, 2.7-30). The median duration of hospital stay following the initial P aeruginosa isolate was 7 days. Emergence of resistance, but not baseline resistance, was significantly associated with a longer hospital stay (P<.001 and P=.71, respectively). The average daily hospital charge was $2059. Neither baseline resistance nor emergence of resistance had a significant effect on the daily hospital charge. In a matched cohort analysis, a trend was seen toward increased total charges in patients demonstrating emergence of resistance (difference, $7340; P=.14).
  
  
  CONCLUSIONS
  Emergence of antibiotic resistance in P aeruginosa results in severe adverse outcomes. Efforts should be directed toward early detection and prevention of emergence of antibiotic resistance.
authors.affiliation: Division of Infectious Diseases, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Carmeli
authors.forename: N
authors.initials: N
authors.lastname: Troillet
authors.forename: A W
authors.initials: AW
authors.lastname: Karchmer
authors.forename: M H
authors.initials: MH
authors.lastname: Samore
mesh_terms: D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000382:microbiology; D001900:Boston; D004352:Drug Resistance, Microbial; D005260:Female; D006745:Hospital Bed Capacity, 300 to 499; D017722:Hospital Charges; D017052:Hospital Mortality; D006784:Hospitals, Teaching / Q000191:economics* / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000191:economics* / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012306:Risk