A Real-world Multicenter Outpatient Experience of Ceftolozane/Tazobactam

Background Ceftolozane/tazobactam (C/T) is indicated for the treatment of complicated intra-abdominal infection (IAI), complicated urinary tract infection (UTI), and hospital-acquired/ventilator-associated bacterial pneumonia caused by susceptible bacteria. As real-world data are limited, we report utilization and associated outcomes of C/T use in the outpatient setting. Methods This is a multicenter, retrospective study of patients who received C/T between May 2015 and December 2020. Demographics, infection types, C/T utilization characteristics, microbiology, and health care resource utilization were collected. Clinical success was defined as complete or partial symptom resolution at completion of C/T. Persistent infection and discontinuation of C/T were deemed nonsuccess. Logistic regression analysis was used to identify predictors associated with clinical outcomes. Results A total of 126 patients (median age, 59 years; 59% male; median Charlson index, 5) from 33 office infusion centers were identified. Infection types included 27% bone and joint infection (BJI), 23% UTI, 18% respiratory tract infection (RTI), 16% IAI, 13% complicated skin and soft tissue infection (cSSTI), and 3% bacteremia. The median daily dose of C/T was 4.5 g, primarily administered via elastomeric pumps as intermittent infusion. The most common gram-negative pathogen was P. aeruginosa (63%), 66% of which was multidrug-resistant and 45% carbapenem-resistant. Enterobacterales was identified in 26% of isolates, of which 44% were extended-spectrum beta-lactamase producers. The overall clinical success rate of C/T was 84.7%. Nonsuccessful outcomes were due to persistent infections (9.7%) and drug discontinuations (5.6%). Conclusions C/T was successfully used in the outpatient setting to treat a variety of serious infections with a high prevalence of resistant pathogens. C/T was successfully used in patients with a variety of serious infections, significant comorbidities, and a high prevalence of resistant pathogens in the outpatient setting.