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.