LAUSR

Learning Objectives: Pseudomonas aeruginosa (PsA) is a significant pathogen associated with severe invasive infections requiring early appropriate therapy, particularly in critically ill patients (pts). Ceftolozane/tazobactam (C/T) is an anti-pseudomonal agent indicated for cUTI and cIAI and currently being studied for ventilated nosocomial pneumonia. This study evaluated C/T for the treatment of PsA from a US hospital database. Methods: This is a retrospective cohort of adult inpatients in the Premier Healthcare Database from 1/1/15–6/30/17, who received > 2 consecutive days of C/T and had a positive PsA. Multidrug resistance (MDR) was resistance or intermediate to >1 agent in > 3 antimicrobial classes. Extensively beta-lactam resistant (EBR) was resistance to all of the following: ceftazidime or cefepime, meropenem or imipenem or doripenem, and piperacillin/tazobactam. Therapy was empiric if given -2 to 2 days; early-directed 3–6 days; late-directed 7–10 days from index culture. Outcomes included median (IQR) total length of stay (LOS) and antibiotic associated LOS (days on any antibiotic for index infection), 30-day mortality, and readmissions. Results: A total of 199 patients had a positive PsA culture. Mean age was 58.6 ± 16.6 years, 61% were male and 72% were Caucasian. The most common comorbidities were chronic pulmonary disease (41%), renal disease (29%), and diabetes (28%) with 35% having a prior hospitalization within 30 days. The mean Charlson score was 2.9 ± 2.5. Over half (54%) of patients were in the ICU, 53% were mechanically ventilated, 13% were on dialysis and 64% had sepsis. Half of C/T was early-directed therapy, 34% was empiric and 16% was late-directed. The majority of PsA was MDR (39%) and an additional 38% were EBR. The most common source of infection was respiratory (57%). The median number of days from admission to first day of C/T was 5 (3–14) and median days of C/T was 8 (4–13). The median antibiotic associated LOS was 10 (6–15) and total LOS was 18 (10–37) days. 30-day mortality was 14%. Infection related readmissions were 8%. Conclusions: Most of C/T’s usage was among critically ill, complex pts with MDR and EBR. The majority of pts received C/T as empiric or early-directed therapy which may have contributed to the successful outcomes, despite the complex nature of these pts.