title: Risk factors for and impact of infection or colonization with aztreonam-resistant Pseudomonas aeruginosa.
abstract: OBJECTIVE
  To identify risk factors for infection or colonization with aztreonam-resistant Pseudomonas aeruginosa and examine the impact of this organism on mortality.
  
  
  METHODS
  A case-control study was performed to identify risk factors for infection or colonization with aztreonam-resistant P. aeruginosa. A cohort study was subsequently performed to examine the impact of aztreonam resistance on outcomes.
  
  
  METHODS
  A tertiary referral center in southeastern Pennsylvania.Participants. Inpatients with a clinical culture positive for P. aeruginosa between January 1, 1999, and December 31, 2000.
  
  
  RESULTS
  Of 720 P. aeruginosa. isolates, 183 (25.4%) were aztreonam-resistant and 537 (74.6%) were aztreonam susceptible. In a multivariable model, prior fluoroquinolone use (adjusted odds ratio [aOR], 1.81 [95% confidence interval {CI}, 1.17-2.80]), prior use of an antianaerobic agent (aOR, 1.56 [95% CI, 1.06-2.29]), and renal insufficiency (aOR, 1.59 [95% CI, 1.10-2.29]) were associated with infection or colonization with aztreonam-resistant P. aeruginosa, while older age (aOR, 0.98 [95% CI, 0.97-0.99] per year of age) was negatively associated with infection or colonization with this organism. In-hospital mortality was higher among subjects infected or colonized with aztreonam-resistant P. aeruginosa, compared with those who were infected or colonized with aztreonam-susceptible P. aeruginosa (25.7% vs 16.8%; P=.009), but in multivariable analysis, no significant association was found between infection or colonization with aztreonam-resistant P. aeruginosa and mortality.
  
  
  CONCLUSIONS
  Curbing the use of fluoroquinolones and antimicrobials with antianaerobic activity may be an effective strategy to limit the emergence of aztreonam-resistant P. aeruginosa.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. leanne.gasink@uphs.upenn.edu
authors.forename: Leanne B
authors.initials: LB
authors.lastname: Gasink
authors.forename: Neil O
authors.initials: NO
authors.lastname: Fishman
authors.forename: Irving
authors.initials: I
authors.lastname: Nachamkin
authors.forename: Warren B
authors.initials: WB
authors.lastname: Bilker
authors.forename: Ebbing
authors.initials: E
authors.lastname: Lautenbach
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000494:pharmacology*; D001398:Aztreonam / Q000494:pharmacology*; D002353:Carrier State; D016022:Case-Control Studies; D015331:Cohort Studies; D024901:Drug Resistance, Multiple, Bacterial; D024841:Fluoroquinolones / Q000009:adverse effects; D017052:Hospital Mortality; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D015143:Philadelphia / Q000453:epidemiology; D011552:Pseudomonas Infections / Q000401:mortality*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012307:Risk Factors