title: Prevalence of multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacteriaceae among specimens from hospitalized patients with pneumonia and bloodstream infections in the United States from 2000 to 2009.
abstract: BACKGROUND
  Antimicrobial resistance complicates antibiotic selection. Pseudomonas aeruginosa (PA), common in pneumonia and blood stream infections (BSIs), is frequently resistant to multiple antimicrobial classes. Carbapenem-resistant Enterobacteriaceae (CRE) have emerged as a pathogen of concern over the past decade.
  
  
  OBJECTIVE
  To determine the prevalence of CRE and multidrug-resistant PA (MDR-PA) in pneumonia and BSI hospitalizations.
  
  
  METHODS
  Survey of data from a nationally representative sample of microbiology laboratories in 217 hospitals in the United States.
  
  
  METHODS
  We examined Eurofins' The Surveillance Network database from 2000 to 2009 to explore the proportion of all PA in pneumonia and BSI that is MDR. We performed the same analysis for CRE as a proportion of Enterobacteriaceae. We defined MDR-PA as any isolate resistant to ≥3 drug classes. Enterobacteriaceae were CRE if resistant to both a third generation cephalosporin and a carbapenem.
  
  
  RESULTS
  We identified 205,526 PA (187,343 pneumonia; 18,183 BSI) and 95,566 Enterobacteriaceae specimens (58,810 pneumonia; 36,756 BSI). The prevalence of MDR-PA was ∼15-fold higher than CRE in both infection types (pneumonia: 22.0% MDR-PA vs 1.6% CRE; BSI: 14.7% MDR-PA vs 1.1% CRE). There was a net rise in MDR-PA as a proportion of all PA from 2000 to 2009 (BSI: 10.7%-13.5%; pneumonia: 19.2%-21.7%). The CRE phenotype emerged in 2002 in both infection types, peaking in 2008 at 3.6% in BSI and 5.3% in pneumonia, and stabilized thereafter.
  
  
  CONCLUSIONS
  Although CRE organisms have emerged as an important pathogen in BSI and pneumonia, MDR-PA remains more prevalent in the United States.
authors.affiliation: EviMed Research Group, LLC, Goshen, Massachusetts; Department of Public Health, University of Massachusetts, Amherst, Massachusetts.
authors.forename: Marya D
authors.initials: MD
authors.lastname: Zilberberg
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
mesh_terms: D000328:Adult; D000368:Aged; D015780:Carbapenems / Q000494:pharmacology / Q000627:therapeutic use*; D003428:Cross Infection / Q000188:drug therapy* / Q000453:epidemiology; D016208:Databases, Factual; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects* / Q000502:physiology; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000453:epidemiology; D015995:Prevalence; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000453:epidemiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D018805:Sepsis / Q000188:drug therapy / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D015780:Carbapenems