2382. Ceftolozane/Tazobactam for the Treatment of Multidrug-Resistant Pseudomonas aeruginosa Infections in Immunocompromised Patients: A Multi-Center Study

Background Ceftolozane/tazobactam (TOL-TAZ) is a novel cephalosporin antibiotic combined with a known β-lactamase inhibitor. It has activity against some extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and multidrug-resistant Pseudomonas aeruginosa (MDRPA). To date, little experience has been published on outcomes with TOL-TAZ for MDRPA infections in immunocompromised patients. Methods This was a retrospective study of adult patients (≥18 years) with an immunocompromising condition (solid-organ transplant; hematologic malignancy; solid tumors; metastatic cancer) at 20 academic medical centers who had microbiologically confirmed MDRPA isolated in culture and received TOL-TAZ for at least 24 hours. 30-day survival, in-hospital mortality, and the rates of microbiologic and clinical cure were assessed. Results Characteristic Result (N = 65) Immunocompromising condition:Solid-organ transplantSolid tumorLeukemiaLymphoma/multiple myelomaMetastatic cancer n(%)35 (53.8)20 (30.7)4 (6.1)3 (4.6)3 (4.6) Male, n(%) 38 (58.4) Age (median, IQR) 64 (20–87) Charlson Comorbidity Index (median, IQR) 6 (1–12) APACHE II score (median, IQR) 20 (4–41) ICU, n(%) 37(56.9) Hospital day index infection diagnosed (median, IQR) 17 (0–265) Hospital day TOL-TAZ started (median, IQR) 19 (0–284) 3grs q8hrs, n(%)1.5grs q8hrs, n(%) 23 (35.3)23 (35.3) Concomitant IV antibiotics, n(%)Aminoglycoside, n/N(%)Fluoroquinolone, n/N(%)Polymyxin, n/N(%)Β-lactam, n/N(%) 15 (23.0)7/15 (46.7)4/15 (26.7)3/15 (20)1/15 (6.6) TOL-TAZ susceptible isolates, n/N (%) 35/37 (94.6) Outcomes by primary infection Primary infection n (%) 30-day survival n/N(%) Microbiologic cure n/N(%) Clinical cure n/N(%) Pneumonia 33 (50.7) 30/33 (90.9) 24/33 (72.7) 28/33 (84.8) Wound/Bone/Joint 12 (18.4) 8/12 (66.6) 7/12 (58.3) 7/12 (58.3) UTI 9 (13.8) 7/9 (77.7) 7/9 (77.7) 8/9 (88.8) Intra-abdominal 7 (10.7) 7/7 (100) 7/7 (100) 4/7 (57.1) Bloodstream 4 (6.1) 4/4 (100) 4/4 (100) 4/4 (100) Overall outcomes, n(%) 30-day survival 56 (86.1) In-hospital mortality 17 (26.1) Microbiologic cure 49 (75.3) Clinical cure 51(78.4) Conclusion In this study of 65 critically-ill immunocompromised patients, the 30-day survival was 86.1%; clinical cure was78.4% and microbiologic cure 75.3%. TOL-TAZ is a viable option for immunocompromised patients with MDRPA infections. Disclosures J. Gallagher, Achaogen: Consultant, Consulting fee. Merck: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee and Research grant. Allergan: Consultant and Speaker’s Bureau, Consulting fee. Astellas: Consultant and Speaker’s Bureau, Consulting fee. Cempra: Consultant, Consulting fee. Cidara: Consultant, Consulting fee. CutisPharma: Consultant, Consulting fee. Paratek: Consultant, Consulting fee. Shionogi: Consultant, Consulting fee. Tetraphase: Consultant, Consulting fee. Theravance: Consultant, Consulting fee. The Medicines Company: Consultant, Consulting fee. Melinta: Speaker’s Bureau, Consulting fee.