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Background The World Health Organization (WHO) has listed carbapenem-resistant Klebsiella pneumoniae (CRKP) as one of the key pathogens that require the highest priority for containment. However, there is still a lack of systematic reports on bloodstream infections(BSI) caused by CRKP in the southern Sichuan of China. This study aimed to retrospectively analyze the clinical characteristics, risk factors, mortality predictors, and molecular epidemiological features of CRKP-BSI strains in patients from three teaching hospitals in southern Sichuan from 2020 to 2024. Methods Clinical and laboratory electronic medical records of patients with KP-BSI were collected retrospectively. T-tests, Mann-Whitney U tests, logistic regression, and survival curve analyses were used to assess risk factors and mortality predictors. Strains were re-identified and verified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the microbroth dilution method. Molecular typing was based on multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Capsular serotypes, virulence genes, and virulence phenotypes were detected using polymerase chain reaction (PCR), sequencing, and serum resistance assays. Results A total of 430 cases meeting the criteria were included, of which 66 were CRKP BSI cases. The highest isolation rate of CRKP BSI was in the intensive care unit (ICU, 28.8%). The resistance rate of CRKP to carbapenems was above 92.2%, and the 28-day mortality rate of CRKP-BSI patients was 43.9%. Multivariate analysis showed that pulmonary infection ( P = 0.021), ICU stay 3 days ( P = 0.029), various invasive catheters ( P 0.001), and combination with three or more antibiotics ( P 0.001) were independent risk factors for CRKP-BSI. Mechanical ventilation ( P = 0.014) and receipt of corticosteroids 7 days ( P = 0.028) were independent risk factors for patient mortality, with the latter also significantly associated with shortened survival time. Molecular epidemiology revealed that ST11 was the dominant clone (43.33%), with three new sequence types identified: ST6845, ST6846, and ST6847. The most common carbapenemase gene was blaKPC-2 (60.0%) and blaNDM-5 (20.0%), and the most common virulence gene was ybtA (76.7%). The outer membrane porin genes ompk35 and ompk36 were detected in 96.7% and 83.3% of the strains, respectively. The positivity rate for biofilm formation was 83.3%, while the positivity rate for the hypermucoviscous phenotype (string test) was 6.67%, and the serum resistance phenotype was detected in 36.7% of cases. Conclusion Carbapenem-resistant Klebsiella pneumoniae (CRKP) in southern Sichuan, China, is characterized by high resistance rates, the continuous emergence of novel clones, and elevated patient mortality. These findings underscore the urgent need for enhanced surveillance that integrates clinical and molecular epidemiology with targeted interventions. This study provides a robust scientific foundation for optimizing the clinical management of CRKP bloodstream infections. This study provides a scientific basis for optimizing clinical management strategies for CRKP-BSI.
Xie et al. (Mon,) studied this question.