1407. Risk Factors for Infection or Colonization with CTX-M Extended-Spectrum Beta-Lactamase (ESBL)-Positive Escherichia coli
Session: Poster Abstract Session: Epidemiology of Multiple Drug-Resistant Gram Negative Rods
Saturday, October 20, 2012
Room: SDCC Poster Hall F-H
  • CTXM.pdf (213.6 kB)
  • Background: Infections with extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are associated with increased morbidity, mortality, and healthcare costs. In the past decade, there has been a significant increase in the prevalence of Enterobacteriaceae that produce CTX-M-type ESBLs. The objective of this study was to evaluate risk factors for infection or colonization with CTX-M-positive Escherichia coli.

    Methods: A case-control study was conducted within a university health system from January 2007 to December 2008. All patients with clinical cultures with E. coli demonstrating resistance to extended-spectrum cephalosporins were included. The presence of the blaCTX-M gene was detected by polymerase chain reaction. Case patients were designated as those with cultures positive for CTX-M-positive E. coli, and control patients as those with non-CTX-M-producing E. coli. Multivariable logistic regression analyses were performed to evaluate risk factors for CTX-M-positive isolates.

    Results: A total of 146 unique patients with clinical cultures with E. coli resistant to extended-spectrum cephalosporins were identified during the two year study period. Of these, 83 (56.8%) patients had cultures with CTX-M-positive E. coli. The majority of isolates (62.6%) belonged to CTX-M group I. On multivariable analyses, there was a significant association between infection or colonization with CTX-M-type beta-lactamase-positive E. coli and receipt of piperacillin-tazobactam in the 30 days prior to the culture date (odds ratio [OR], 7.36; 95% confidence interval [CI], 1.61-33.8; P=0.01) and a urinary culture source (OR, 0.36; 95% CI, 0.17-0.77; P=0.008). Resistance to fluoroquinolones was significantly higher in isolates from cases as opposed to controls (90.4% and 50.8%, respectively; P<0.001).

    Conclusion: Non-urinary sources of clinical cultures and recent use of piperacillin-tazobactam conferred an increased risk of colonization or infection with CTX-M-positive E. coli as opposed to other ESBL types. Future studies will need to focus on outcomes associated with infections due to CTX-M-positive E. coli, as well as infection control strategies to limit the spread of these increasingly common organisms.

    Jennifer Han, MD1, Kei Kasahara, MD2, Paul H. Edelstein, MD3, Warren Bilker, PhD4,5, Ebbing Lautenbach, MD, MPH, MScE1,4,5 and the CDC Prevention Epicenter Program, (1)Division of Infectious Diseases, Dept. of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, (2)Nara Medical University, Kashihara, Japan, (3)Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, (4)Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA, (5)Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA


    J. Han, None

    K. Kasahara, None

    P. H. Edelstein, None

    W. Bilker, None

    E. Lautenbach, Merck: Grant Investigator, Research grant
    AstraZeneca: Grant Investigator, Research grant
    3M: Grant Investigator, Research grant
    Cubist: Grant Investigator, Research grant

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