1580. Prevalence of antibiotic resistance among P. aeruginosa in US hospitals, 2000-2009
Session: Poster Abstract Session: Multidrug-Resistant Gram Negative Rods
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • PA_LACTAM_FINAL_Cubist_1580-1.pdf (630.1 kB)
  • Background: P. aeruginosa (PA) represents an important cause of severe infection in hospitalized patients. Initially appropriate empiric antibiotic therapy is a key determinant of outcome. Appropriate initial antibiotic selection is predicated on understanding the epidemiology of resistance to commonly used antibiotics either as single agents or as parts of combination regimens. We explored resistance among PA to frequently utilized antibiotic regimens over time in the US.

    Methods: We analyzed a nationally representative US-based microbiology database, Eurofins TSN, between years 2000 and 2009. We examined the prevalence of PA’s resistance to the following antibiotics: piperacillin/tazobactam (PTZ), ceftazidime (TAZ), imipenem (IMI), or meropenem (MER) alone, and combinations of PTZ+ciprofloxacin (CIP), TAZ+CIP, IMI+CIP, MER+CIP, PTZ+gentamicin (GEN), TAZ+GEN, IMI+GEN, MER+GEN. We evaluated specimens from pneumonia (PNE), blood stream (BSI), urinary tract (UTI) and complicated intra-abdominal (IAI) infections.      

    Results: Among the 327,912 PA specimens 57.1% were PNE, 35.1% UTI, 5.6% BSI and 2.2% IAI. Overall, the highest prevalence of resistance to single therapy was TAZ (24.8%) and combination IMI+CIP (17.3%). The lowest rate of resistance was to PTZ as a single agent (13.4%) and PTZ+GEN as combination (7.9%). PNE accounted for the highest proportion of resistance to all regimens examined, ranging from 9.5% PTZ+GEN to 29.5% TAZ. Between 2000 and 2009, while resistance rates rose to PTZ (12.4% to 15.0%), IMI (20.8% to 25.2%), MER (19.5% to 24.2%), PTZ+CIP (8.8% to 10.1%), IMI+CIP (14.7% to 18.3%) and MER+CIP (14.9% to 17.4%), those to the other regimens remained stable with some fluctuations. 

    Conclusion: Resistance among PA to routine anti-pseudomonal regimens is high, with the highest levels observed in PNE. While they have remained stable to some potential regimens, resistance rates to others have increased over the decade examined. The most pronounced rise in PA resistance was to regimens containing carbapenems, irrespective of concomitant fluoroquinolone use. These trends must inform not only empiric treatment of serious infections, but also the approaches to antibiotic stewardship.

    Marya D. Zilberberg, MD, MPH, University of Massachusetts and Evimed Research Group, LLC, Goshen, MA and Andrew F. Shorr, MD, MPH, Pulmonary and Critical Care Medicine, Washington Hospital Center, Washington, DC


    M. D. Zilberberg, Cubist: Consultant and Grant Investigator, Research support

    A. F. Shorr, Cubist: Consultant, Consulting fee

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