A Real-world Multicenter Outpatient Experience of Ceftolozane/Tazobactam

Area of Science:

• Infectious Diseases
• Pharmacology
• Clinical Microbiology

Background:

• Ceftolozane/tazobactam (C/T) is approved for complicated intra-abdominal infections (IAI), complicated urinary tract infections (UTI), and hospital-acquired/ventilator-associated pneumonia.
• Limited real-world data exists on C/T utilization and outcomes in the outpatient setting.

Purpose of the Study:

• To evaluate the utilization and clinical outcomes of ceftolozane/tazobactam in an outpatient setting.
• To identify factors associated with successful clinical outcomes.

Main Methods:

• Multicenter, retrospective study of 126 patients receiving C/T between May 2015 and December 2020.
• Data collected included demographics, infection types, C/T administration, microbiology, and healthcare resource utilization.
• Clinical success was defined as symptom resolution; logistic regression identified outcome predictors.

Main Results:

• C/T was administered to patients with bone and joint infections (27%), UTIs (23%), respiratory tract infections (18%), IAIs (16%), and complicated skin and soft tissue infections (13%).
• The most common pathogen was multidrug-resistant *Pseudomonas aeruginosa* (63%).
• Overall clinical success rate was 84.7%, with persistent infection (9.7%) and discontinuation (5.6%) being primary reasons for nonsuccess.

Conclusions:

• Ceftolozane/tazobactam demonstrated successful utilization in the outpatient setting for diverse serious infections.
• High rates of multidrug-resistant pathogens, including *P. aeruginosa*, were treated effectively.
• Real-world data supports C/T as a viable option for outpatient management of complex bacterial infections.