181Empiric Coverage of ICU Patients for Infections Due to Beta-lactam Resistant Pseudomonas aeruginosa with Combination Therapy: A Needs Assessment

Background. Empiric antimicrobials for critically-ill patients routinely include combination therapy for patients at risk for infection from P. aeruginosa. In 2013, in vitro susceptibility to anti-pseudomonal beta-lactams, ciprofloxacin and tobramycin among ICU isolates at of P. aeruginosa was < 85%, 70% and >90%, respectively. This prompted the question of whether an aminoglycoside should routinely be administered with an anti-pseudomonal beta-lactam antibiotic as empiric therapy in ICU patients. Methods. The study aimed to describe the epidemiology and patient outcomes of infection due to P. aeruginosa with in vitro resistance to at least one anti-pseudomonal beta-lactam agent. A retrospective study of patients admitted to an ICU between January 1 and December 31, 2013 with at least 1 isolate of P. aeruginosawith in vitro resistance to at least one of the anti-pseudomonal beta-lactam agents was completed. Results. Overall, 61 ICU patients out of 15, 311 ICU admissions (0.4%) had 100 isolates with resistance to at least one anti-pseudomonal beta-lactam agent. Nineteen (31.2%) had >1 isolate recovered during the calendar year and 38 (62.3%) had structural respiratory tract changes and/or depressed CNS function that likely predisposed to P. aeruginosa colonization or infection. Sepsis was listed as a diagnosis in 10 patients. Based on empiric choices of therapy, 21 patients had a “mismatch” in therapy, based on drug administration and in vitro susceptibility results. Twenty-one (34.4%) of 61 patients died during the hospitalization or shortly thereafter. Of these, 8 (38.1%) had received mismatched therapy. In only one case, death was possibly related to mismatched therapy. Conclusion. The results of this study suggest that despite the concerning decrease in susceptibility of both beta-lactams and quinolones to P. aeruginosa, the recovery of beta-lactam resistant P. aeruginosa in our ICU cohort was uncommon and did not result in a significant worsening of patient outcomes. Therefore, even with decrease in susceptibilities, routine use of empiric combination therapy that includes an aminoglycoside does not seem warranted at this time. Disclosures. All authors: No reported disclosures.