195. Antimicrobial Stewardship Incorporating New Antimicrobials for Use against Multi-Drug Resistant Pseudomonas aeruginosa in Cystic Fibrosis

Abstract

BackgroundCystic fibrosis (CF) is a life-limiting genetic disease affecting approximately 80,000 people worldwide, including 30,000 in the United States. Chronic Pseudomonas aeruginosa (PA) infections in CF often develop to be multidrug-resistant (MDR) and are associated with worse clinical outcomes. Ceftolozane/Tazobactam (C/T) has shown benefits over other standards of therapy in selected populations with MDR-PA infections, but studies are lacking in the CF population. The objective of this study was to evaluate the current use and antimicrobial stewardship of C/T in CF patients with MDR-PA.MethodsThis is a retrospective study of hospitalized CF patients with infections due to positive cultures for MDR-PA from 2016–2019 at Baylor St. Luke’s Medical Center in Houston, Texas. Electronic medical records were reviewed for patient demographics, presence of infectious diseases (ID) consult, antibiotics use, and clinical outcomes. A descriptive analysis was performed to compare the patient demographics and clinical outcomes between patients receiving C/T-based and non-C/T therapies.ResultsA total of 56 CF patients with positive MDR-PA cultures were identified (18 receiving C/T and 38 receiving non-C/T antibiotics). Most MDR-PA was cultured from the lungs (94.6%, 54/56). Patient age, weight, and body mass index were similar between those receiving C/T and non-C/T therapies as was the overall duration of antibiotic therapy 16.3 (± 8.7) vs. 13.9 (± 3.5) days in C/T and non-C/T groups, respectively. More patients in the C/T group had severe forced expiratory volume in 1 s (FEV1) [£40%] at baseline (66.7% vs. 21.1%) and higher ICU admission rates (44.4% vs 2.6%). All C/T patients had an ID consult placed (3 ± 3.1 days after admission) but none in the non-C/T group. The 30-day recurrent pulmonary exacerbation rate was comparable between C/T and non-C/T groups (22.2% vs. 15.8%).ConclusionC/T was reserved for the sickest group of CF patients with severe FEV1. Given the devastating disease progression with MDR organisms in CF, new antibiotics with better clinical outcomes against chronic MDR-PA should be considered earlier in therapy for this population. Larger studies are warranted to analyze cost-effectiveness and clinical outcomes.Disclosures Kevin W. Garey, PharMD, MS, FASHP, Merck & Co. (Grant/Research Support, Scientific Research Study Investigator)