Molecular Epidemiological Characteristics of Clinical Isolates of CRKP Resistant to Imipenem/Relebactam

This study analyzed carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from a tertiary hospital to determine their level of resistance to imipenem/relebactam (IMR). A total of 174 CRKP clinical isolates collected between January 2023 and June 2024 were categorized, as IMR-sensitive ( n = 151) or IMR-resistant ( n = 23) based on broth microdilution minimum inhibitory concentrations (MICs). No significant differences were found in patient demographics, comorbidities, or length of hospitalization between the two groups. The resistant strains mainly originated from sputum samples (78.3%) and intensive care units. Univariate analysis showed lower resistance to amikacin, cefepime, and tobramycin, higher rmpA detection, and lower bla CTX-M , iutA , and rmpA2 detection in resistant strains (unadjusted p < 0.05); however, none remained significant after FDR correction. Both groups were predominantly ST11, with the predominant capsular types being K64 and K25. These IMR-resistant CRKP strains exhibit multidrug resistance (except to polymyxin and tigecycline) and carry multiple resistance and virulence genes, highlighting the need for enhanced surveillance.