Impact of Ceftolozane-Tazobactam vs. Best Alternative Therapy on Clinical Outcomes in Patients with Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Lower Respiratory Tract Infections

INTRODUCTION: Infections caused by multidrug-resistant (MDR), extensively drug-resistant (XDR), and difficult-to-treat (DTR) Pseudomonas aeruginosa are increasingly challenging to combat. Ceftolozane-tazobactam (C/T) is a novel β-lactam-β-lactamase inhibitor combination now commonly used to treat MDR and XDR P. aeruginosa. Lower respiratory tract infections (LRTIs) remain the most common source of infection caused by MDR/XDR P. aeruginosa. Comparative effectiveness studies to date have been limited by the type of comparator agents (i.e., aminoglycosides and polymyxins) and the inclusion of multiple infection sources (i.e., urinary tract, abdominal, skin and soft tissue, etc.). METHODS: We performed a multicenter, retrospective analysis of adults with LRTI caused by MDR or XDR P. aeruginosa admitted from January 2014 to December 2019. We aimed to compare clinical outcomes between patients who received C/T (n = 118) versus best alternative therapy (n = 88). The primary outcome was clinical failure, defined as 30-day mortality and/or an adverse drug reaction on antibiotic therapy. RESULTS: Two hundred and six patients met inclusion criteria. The C/T group had a significantly higher proportion of XDR P. aeruginosa and ventilator-associated bacterial pneumonia (VABP). After multivariable logistic regression, C/T treatment was independently associated with a 73.3% reduction in clinical failure compared to those who received best alternative therapy (P \u3c 0.001). The number needed to harm with best alternative therapy was 3. CONCLUSION: Our results suggest that C/T is a safe and effective therapeutic regimen for patients with MDR and XDR P. aeruginosa LRTI

Nephrotoxicity of Vancomycin in Combination with Beta-lactam Agents: Ceftolozane-tazobactam vs. Piperacillin-tazobactam

BACKGROUND: Vancomycin (VAN)-associated acute kidney injury (AKI) is increased when VAN is combined with certain beta-lactam (BL) such as piperacillin-tazobactam (TZP) but not had been evaluated with ceftolozane-tazobactam (C/T). We aim to investigate the AKI incidence of VAN in combination with C/T (VAN/C/T) compared to VAN in combination to TZP (VAN-TZP). METHOD: We conducted a multi-center observational comparative study across the United States. The primary analysis was a composite outcome of AKI: 1) RIFLE, 2) AKIN, or 3) VAN-induced-nephrotoxicity according to the consensus guidelines. Multivariable logistic regression analysis had been conducted to adjust for confounding variables and stratified Kaplan-Meir analysis to assess the time-to-nephrotoxicity between the two groups. RESULTS: We included (n = 90) VAN/C/T and (n = 284) VAN-TZP at an enrollment ratio of 3:1. The primary outcome occurred in 12.2% vs. 25.0% in the VAN-C/T and VAN-TZP groups, respectively (P = 0.011). After adjusting for confounding variables, VAN-TZP was associated with increased odds of AKI compared with patients receiving VAN-C/T; with an aOR of 3.308 [1.560-6.993]. Results of the stratified Kaplan-Meir with log-rank time-to-nephrotoxicity analysis indicate that time to AKI was significantly shorter among patients receiving VAN-TZP (P = 0.004). Cox proportional hazards analysis demonstrated that TZP was consistent with the primary analysis (P = 0.001). CONCLUSIONS: Collectively, our results suggest that the AKI is not likely to be related to tazobactam but rather to the piperacillin which is a component in the VAN-TZP combination but not the VAN-C/T