In Vitro Activity of Imipenem/Relebactam and Ceftolozane/Tazobactam Against Multidrug-Resistant Klebsiella pneumoniae: A Retrospective Single-Center Study in China.
5 affiliations
- 1Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China.
- 2Department of Pulmonary and Critical Care Medicine, Peking University Third Hospital, Beijing 100191, China.
- 3Department of Infectious Disease, Peking University Third Hospital, Beijing 100191, China.
- 4Department of Laboratory Medicine, Peking University Third Hospital, Beijing 100191, China.
- 5Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, Beijing 100191, China.
Abstract
Background
Multidrug-resistant Klebsiella pneumoniae (MDR-KP) is a global health threat with limited treatment options. Comparative in vitro data for imipenem-relebactam (I/R) and ceftolozane-tazobactam (C/T) across diverse MDR-KP clinical populations remain limited.Methods
Susceptibility to I/R and C/T was determined by Etest. Whole-genome sequencing was used to identify sequence types, resistance genes, and virulence genes, with hypervirulent K. pneumoniae (hvKP) defined by genomic criteria.Results
A total of 312 nonduplicate MDR-KP clinical isolates, including 70.8% carbapenem-resistant K. pneumoniae (CR-KP), 56.7% difficult-to-treat resistant K. pneumoniae (DTR-KP), and 28.2% carbapenem-resistant hvKP (CR-hvKP), were retrospectively analyzed. I/R resistance was low across all subgroups (overall 3.8%, CR-KP 5.0%, DTR-KP 6.2%, CR-hvKP 2.3%) and across specimen types (0-9.6%; blood 3.8%). In contrast, C/T resistance was higher (overall 57.7%, CR-KP 79.2%, DTR-KP 91.0%, CR-hvKP 84.1%), with the highest rate in respiratory isolates (63.0%), followed by blood (57.7%) and urine (50.0%). Among extended-spectrum β-lactamase (ESBL)-producing isolates, I/R and C/T resistance rates were 2.1% and 12.4%, respectively. Although C/T resistance was higher in hvKP than in classic K. pneumoniae in unadjusted analysis, hvKP was not independently associated with increased C/T resistance after adjustment. Instead, ST11, ST15, ST307, blaKPC-2, and blaNDM-1 were independently associated with C/T resistance. For I/R, blaNDM-1 was associated with resistance.Conclusions
I/R was active across MDR-KP subgroups including CR-hvKP and DTR-KP. C/T worked mainly against ESBL-producers. These findings highlight the importance of resistance genotyping when interpreting susceptibility to these agents.
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BibTeX
@article{yi2026vitro,
title = {{In Vitro Activity of Imipenem/Relebactam and Ceftolozane/Tazobactam Against Multidrug-Resistant Klebsiella pneumoniae: A Retrospective Single-Center Study in China.}},
author = {Juan Yi and Chao Liu and Ping Yang and Bowen Wang and Jiajia Zheng and Ning Shen},
journal = {Antibiotics (Basel, Switzerland)},
year = {2026},
month = sep,
doi = {10.3390/antibiotics15100947},
url = {https://europepmc.org/article/MED/42938688},
note = {CC BY},
}
RIS
TY - JOUR
TI - In Vitro Activity of Imipenem/Relebactam and Ceftolozane/Tazobactam Against Multidrug-Resistant Klebsiella pneumoniae: A Retrospective Single-Center Study in China.
AU - Juan Yi
AU - Chao Liu
AU - Ping Yang
AU - Bowen Wang
AU - Jiajia Zheng
AU - Ning Shen
PY - 2026
DA - 2026/09/23
JO - Antibiotics (Basel, Switzerland)
DO - 10.3390/antibiotics15100947
UR - https://europepmc.org/article/MED/42938688
AB - Background Multidrug-resistant Klebsiella pneumoniae (MDR-KP) is a global health threat with limited treatment options. Comparative in vitro data for imipenem-relebactam (I/R) and ceftolozane-tazobactam (C/T) across diverse MDR-KP clinical populations remain limited.Methods Susceptibility to I/R and C/T was determined by Etest. Whole-genome sequencing was used to identify sequence types, resistance genes, and virulence genes, with hypervirulent K. pneumoniae (hvKP) defined by genomic criteria.Results A total of 312 nonduplicate MDR-KP clinical isolates, including 70.8% carbapenem-resistant K. pneumoniae (CR-KP), 56.7% difficult-to-treat resistant K. pneumoniae (DTR-KP), and 28.2% carbapenem-resistant hvKP (CR-hvKP), were retrospectively analyzed. I/R resistance was low across all subgroups (overall 3.8%, CR-KP 5.0%, DTR-KP 6.2%, CR-hvKP 2.3%) and across specimen types (0-9.6%; blood 3.8%). In contrast, C/T resistance was higher (overall 57.7%, CR-KP 79.2%, DTR-KP 91.0%, CR-hvKP 84.1%), with the highest rate in respiratory isolates (63.0%), followed by blood (57.7%) and urine (50.0%). Among extended-spectrum β-lactamase (ESBL)-producing isolates, I/R and C/T resistance rates were 2.1% and 12.4%, respectively. Although C/T resistance was higher in hvKP than in classic K. pneumoniae in unadjusted analysis, hvKP was not independently associated with increased C/T resistance after adjustment. Instead, ST11, ST15, ST307, blaKPC-2, and blaNDM-1 were independently associated with C/T resistance. For I/R, blaNDM-1 was associated with resistance.Conclusions I/R was active across MDR-KP subgroups including CR-hvKP and DTR-KP. C/T worked mainly against ESBL-producers. These findings highlight the importance of resistance genotyping when interpreting susceptibility to these agents.
SN - 2079-6382
ER -