In vitro activity of cefepime-zidebactam, ceftolozane-tazobactam, ceftazidime-avibactam, imipenem-relebactam, and other comparators against imipenem-non-susceptible Pseudomonas aeruginosa in Taiwan, 2022.

OBJECTIVES: The global expansion of antimicrobial-resistant Pseudomonas aeruginosa, particularly imipenem-non-susceptible (INS) strains poses a formidable health threat. The COVID-19 pandemic has exacerbated antimicrobial resistance trends. We compared the pre- and post-pandemic antibiotic resistance patterns of INS-P. aeruginosa in Taiwan.

METHODS: We analysed 503 P. aeruginosa isolates collected through the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program during 2022. Minimum inhibitory concentrations of various antibiotics were determined by using broth microdilution. Carbapenemase-encoding genes were identified via multiplex PCR. Antimicrobial resistance trends were compared with data from 2018.

RESULTS: INS-P. aeruginosa comprised 16.9% (85/503) of isolates and exhibited high-level multi-drug resistance. Novel β-lactam-β-lactamase inhibitor combinations (BL-BLIs) demonstrated the highest activity, with 89.4% of INS isolates remaining susceptible to cefepime-zidebactam. However, the susceptibility rates of INS-P. aeruginosa isolates to other BL-BLIs and comparators declined between 2018 and 2022. Specifically, susceptibility to ceftazidime-avibactam and imipenem-relebactam declined significantly from 81.5% and 85.2% in 2018 to 64.7% and 63.5% in 2022, respectively (both P < 0.05). Additionally, only 70.6% of isolates obtained during 2022 were susceptible to ceftolozane-tazobactam. Carbapenemase genes were detected in 10.6% of isolates, with a notable increase in blaKPC and blaIMP prevalence compared to pre-pandemic data.

CONCLUSION: The COVID-19 pandemic intensified resistance trends in INS-P. aeruginosa in Taiwan, with increasing prevalence and diversity of carbapenemase-encoding genes. Continuous monitoring and expanded research are essential to combat evolving resistance patterns.