Antimicrobial activities of ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/relebactam, meropenem/vaborbactam, and comparators against Pseudomonas aeruginosa from patients with skin and soft tissue infections

Background: The limited armamentarium against multidrug-resistant Gram-negative bacilli led to the development of a new generation of beta-lactam/beta-lactamase inhibitor combinations (BL/BLI). Objectives: To evaluate the in vitro activity of ceftazidime/avibactam, ceftolozane/tazobactam, meropenem/vaborbactam, and imipenem/relebactam against Pseudomonas aeruginosa isolates recovered from patients hospitalized with skin and soft tissue infections (SSTIs) in several countries around the world. Methods: A total of 360 P. aeruginosa isolates were consecutively collected from 47 medical centers located in Western Europe, Eastern Europe, the Asia-Pacific region, and Latin America. Susceptibility testing was performed by broth microdilution method at a monitoring laboratory. EUCAST breakpoints were applied. Results: Ceftazidime/avibactam (98.3% susceptible), ceftolozane/tazobactam (98.6% susceptible), and imipenem/relebactam (98.3% susceptible) were the most active compounds after colistin (100.0% susceptible) and retained activity against isolates nonsusceptible to piperacillin/tazobactam, meropenem, imipenem, and/or ceftazidime. Meropenem-vaborbactam was active against 94.2% of isolates. Ceftazidime/avibactam was the most active BL/BLI against meropenem-nonsusceptible (92.6% susceptible) and imipenem-resistant (93.8% susceptible) isolates, whereas ceftolozane/tazobactam was the most active BL/BLI against piperacillin/tazobactam-resistant (91.1% susceptible) and ceftazidime-resistant (91.7% susceptible) isolates. Conclusions: The recently approved BL/BLIs demonstrated potent activity and broad coverage against contemporary P. aeruginosa isolates from patients with SSTIs. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.