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

BACKGROUNDAntimicrobial 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. OBJECTIVETo determine the prevalence of CRE and multidrug-resistant PA (MDR-PA) in pneumonia and BSI hospitalizations. DESIGNSurvey of data from a nationally representative sample of microbiology laboratories in 217 hospitals in the United States. METHODS/SETTINGWe 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. RESULTSWe 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 approximate to 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. CONCLUSIONSAlthough CRE organisms have emerged as an important pathogen in BSI and pneumonia, MDR-PA remains more prevalent in the United States. Journal of Hospital Medicine 2013;8:559-563. (c) 2013 Society of Hospital Medicine