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630 Cefepime Resistance in Pseudomonas Aeruginosa: Risk Factors and Clinical Outcomes

Sunday, April 3, 2011: 3:00 PM
Coronado A (Hilton Anatole)
Ehimare Akhabue, MD , University of Pennsylvania School of Medicine, Philadelphia, PA
Marie Synnestvedt, PhD , University of Pennsylvania School of Medicine, Philadelphia, PA
Mark Weiner, MD , University of Pennsylvania School of Medicine, Philadelphia, PA
Warren Bilker, PhD , University of Pennsylvania School of Medicine, Philadelphia, PA
Ebbing Lautenbach, MD, MPH, MSCE , University of Pennsylvania School of Medicine, Philadelphia, PA
Background: Pseudomonas aeruginosa is one of the most common and important causes of gram negative healthcare-acquired infections. Resistance to extended-spectrum cephalosporins such as cefepime complicates treatment of these infections. Risk factors for cefepime-resistant P. aeruginosa (CRPA) have not been studied.

Objective: To assess risk factors for CRPA and determine the impact of CRPA on outcomes.

Methods: The study was performed at the Hospital of the University of  Pennsylvania (HUP), a 725-bed tertiary care center, and  Penn Presbyterian Medical Center (PPMC), a 344-bed urban community hospital. The overall and annual prevalence of CRPA among clinical inpatient isolates was determined at the two centers from 2001-2006. For P. aeruginosa isolates during this period, a case-control study was conducted to elucidate the risk factors for CRPA, and a retrospective cohort study was done to determine the association between CRPA and mortality.

Results: Between 2001 and 2006, there was no significant trend in the prevalence of CRPA. Amongst the 2529 unique patients with P. aeruginosa isolates during this period, 213 (8.4%) had CRPA. Independent risk factors [adjusted OR (95%CI); p value] for CRPA were: prior use of an extended-spectrum cephalosphorin [ 2.18 (1.57, 3.04); p<0.001], prior use of an extended-spectrum penicillin [1.91 (1.22, 2.99); p=0.005], prior use of a quinolone [1.96 (1.38, 2.78); p<0.001], and transfer from an outside facility [1.49 (1.09, 2.04); p=0.01]. CRPA patients had an increased 30 day in-hospital mortality (20.2% vs. 13.2%, p=0.007), although CRPA was an independent risk factor for mortality only among blood isolates [RR (95%CI) = 15.55 (3.10, 77.89); p=0.001].

Conclusions: CRPA has important implications for clinical outcomes and strategies to counter its emergence are needed. Recognizing recent prior use of anti-pseudomonal agents both within the same class and from certain other classes will be important in devising successful interventions.