223. Piperacillin/Tazobactam (PT) in the Treatment of Extended Spectrum beta-Lactamase (ESBL) Producing Bacterial Infections
Session: Poster Abstract Session: Antimicrobial Resistance: Clinical Studies
Friday, October 21, 2011
Room: Poster Hall B1
Background: Infections caused by ESBL producing Gram-negative pathogens are often treated with PT based on culture results but clinical data are limited. 

Methods: We performed a retrospective study of patients admitted to the hospital with documented ESBL infections between July 2007 and May 2010.  Patients were included if blood, urine, sputum or other cultures were positive for confirmed ESBL pathogens.  Only the first infection was assessed in patients with recurrent admissions.  Patients were excluded if they were considered colonized or did not receive any antibiotic treatment.  Data collected included residence type (home or extended care facility (ECF)), demographic data, empiric and final antibiotic selection, outcomes and the Charlson Weighted Index of Comorbidity (CWIC). 

Results: Eighty-four patients admitted to our facility met inclusion criteria.  Forty patients received PT and 44 received an alternative agent.  Fifty-three patients had urinary tract infections (UTI), 8 patients had primary bacteremia and the rest had pneumonia, wound infections or other sites.  There was no statistically significant difference in overall mortality for patients who received PT vs a carbapenem or other antibiotic as empiric (6.3% vs 17.5%, p=0.141) or definitive therapy (15.4% vs 10.3%, p=0.59). The CWIC was significantly lower for patients who received PT (4.88±2.93) compared to patients who did not receive PT (6.41±3.71, p=0.040).  Patients with a UTI admitted from an ECF had a lower mortality rate when empiric therapy was PT rather than another antibiotic (7.1% vs 28%, p=0.044).  Patients admitted from home with a UTI were more likely to return home if they received empiric therapy with an antibiotic other than PT (93.3% vs 50%, p=0.035).  There was no difference in the CWIC between the two groups.  There were no differences in outcomes when comparing final antibiotic treatments or comparing carbapenem therapy to all other therapies.

Conclusion: PT appears to be an effective treatment for patients with ESBL producing pathogens when used as either initial or definitive therapy.  There were some observed differences in outcomes for patients with a UTI admitted from home.  Larger prospective randomized studies would be important in confirming our results.  

Subject Category: C. Clinical studies of bacterial infections and antibacterials including sexually transmitted diseases and mycobacterial infections (surveys, epidemiology, and clinical trials)

Elizabeth Bankstahl, MD, Internal Medicine, St John Hospital and Medical Center, Grosse Pointe Woods, MI, Susan Szpunar, PhD, St. John Hospital and Medical Center, Grosse Pointe Woods, MI, Laurence Briski, MD, St John Hospital & Medical Center, Grosse Pointe Woods, MI and Joel Fishbain, MD, Medicine, St. John Hospital and Medical Center, Grosse Pointe Woods, MI


E. Bankstahl, None

S. Szpunar, None

L. Briski, None

J. Fishbain, None

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