Program Schedule

Treatment Outcomes in Patients with Extended-Spectrum Beta-lactamase Producing Organisms

Session: Poster Abstract Session: Treatment of Antimicrobial Resistant Infections
Thursday, October 9, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Background: Extended Spectrum Beta-Lactamase (ESBL) producing organisms are associated with significant morbidity and mortality. In 2010, the Clinical and Laboratory Standards Institute (CLSI) lowered the breakpoints for most cephalosporins. This change was made in part because minimum inhibitory concentrations were thought to be more predictive of outcomes than the presence of an ESBL enzyme per se. Our institution implemented these interpretative criteria in April 2011 but continued to perform ESBL testing for quality assurance purposes without reporting the results to clinicians. Therefore, we sought to evaluate the impact of the change in ESBL reporting on treatment outcomes, prescribing patterns, and cost savings. Methods: Patients with blood cultures positive for ESBL-producing Enterobacteriaecae from January 2007 to December 2009 (i.e. PRE) were compared to patients from April 2011 to December 2013 (i.e. POST). Results: We identified 80 patients with ESBL-producing Enterobacteriaecae, with 38 patients (41 isolates) in the PRE group and 42 patients (43 isolates) in the POST group. Baseline characteristics were similar between groups. The organisms identified in both groups were E.coli (64%), K.pneumoniae(23%), E.cloacae(7%), and others (6%). The recurrence rate in the PRE and POST (12% and 7%, p = 0.2), the length of stay (median 19 vs 13 days, p=0.1) and 30-day all-cause mortality (32% vs 19%, p=0.3) were not statistically significantly different between both groups. 80% (34) of patients in both groups were treated with carbapenems; 58% (20) of these patients had isolates which were also susceptible or susceptible dose-dependent to cefepime based on the new CLSI criteria. Approximately $400 per patient would have been saved if cefepime had been used instead. Conclusion: The change in ESBL reporting was not associated with a statistically significant change in treatment outcomes or prescribing patterns or drug costs. This may have implications for improved stewardship.
Eunbae Lee, PharmD, Pharmacy, University of Washington, Seattle, WA, Susan Butler-Wu, PhD, Department of Laboratory Medicine, University of Washington, Seattle, WA, Paul Pottinger, MD, Division of Allergy and Infectious Disease, University of Washington, Seattle, WA, Moni Blazej Neradilek, The Mountain-Whisper-Light Statistics, Seattle, Seattle, WA and Rupali Jain, PharmD, Pharmacy, University of Washington Medical Center, Seattle, WA


E. Lee, None

S. Butler-Wu, Thermo Fisher Scientific: Scientific Advisor, Salary

P. Pottinger, None

M. B. Neradilek, None

R. Jain, None

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