Antimicrobial resistance among imipenem-non-susceptible Escherichia coli and Klebsiella pneumoniae isolates, with an emphasis on novel β-lactam/β-lactamase inhibitor combinations and tetracycline derivatives: The Taiwan surveillance of antimicrobial resistance program, 2020–2022

Background

To determine susceptibility of imipenem-non-susceptible Escherichia coli (INS-EC) and Klebsiella pneumoniae (INS-KP) isolates collected during 2020–2022 through a national surveillance program in Taiwan to novel antibiotics, and to compare the results with those obtained during 2012–2018.

Methods

Minimum inhibitory concentrations were determined by broth microdilution methods. Genes encoding carbapenemases including bla_KPC, metallo-β-lactamase (MBL) genes, and bla_OXA-48 were detected via multiplex PCR. Data retrieved from our 2012–2018 study were used for comparison.

Results

Of 3260 E. coli and 1457 K. pneumoniae isolates collected during 2020–2022, 0.9 % and 9.5 %, were INS-EC and INS-KP, respectively. Cefepime-zidebactam, ceftazidime-avibactam, imipenem-relebactam, and meropenem-vaborbactam were active against 100 %, 75.9 %, 65.5 %, and 79.3 % of 29 INS-EC isolates respectively; and against 100 %, 90.6 %, 64.5 %, and 67.4 % of 138 INS- KP isolates, respectively. Susceptibility was contingent upon carbapenemase types. Susceptibility rates of cefepime-zidebactam and ceftazidime-avibactam remained constant from 2012 to 2018 through 2020–2022 but those of imipenem-relebactam and meropenem-vaborbactam decreased significantly, which may be partially attributable to the increasing prevalence of bla_OXA-48. Eighteen MBL-gene-positive isolates and two bla_KPC-positive isolates were resistant to ceftazidime-avibactam, whereas all were susceptible to cefepime-zidebactam. Tigecycline had a higher susceptibility rate than eravacycline and omadacycline for K. pneumoniae isolates. Lascufloxacin and delafloxacin were effective against fewer than 10 % of INS isolates. Susceptibilities to novel tetracyclines and fluoroquinolones remained similar from 2012 to 2018 through 2020–2022.

Conclusions

This study highlights significant resistance patterns of INS-EC and INS-KP isolates in Taiwan. The declining susceptibility rates and the rising prevalence of genetic resistance determinants highlight the importance of ongoing surveillance and antimicrobial stewardship.