Abstract:Objective To analyze the association of serum levels of cartilage glycoprotein-39（YKL-40），and mitochondrial uncoupling protein 2（UCP2）with the occurrence and prognosis of drug-resistant Klebsiella pneumoniae（KP）sepsis. Methods Prospectively，100 patients with drug - resistant KP sepsis admitted to Suzhou Municipal Hospital Affiliated to Anhui Medical University from January 2022 to June 2023 were selected as the study group，and 103 healthy individuals during the same period were selected as the control group. The study group was further divided into a poor prognosis group（n=38）and a good prognosis group（n=62）based on the 28-day prognosis. Serum levels of YKL-40 and UCP2 were measured using enzyme-linked immunosorbent assay（ELISA）. Multivariate logistic regression analysis was used to identify factors influencing the prognosis of drug - resistant KP sepsis. Receiver operating characteristic（ROC）curves were used to evaluate the predictive value of serum YKL-40 and UCP2 for the prognosis of drug-resistant KP sepsis. Results Serum levels of YKL-40，UCP2，procalcitonin（PCT），and white blood cell count（WBC）were significantly higher in the study group compared to those in the control group （P<0.05）. The poor prognosis group had significantly higher serum levels of YKL-40［（54.15±9.43）ng/mL vs（41.59±5.76）ng/mL，t=8.279，P<0.05］and UCP2［（175.42 ± 26.81）ng/L vs（117.63 ± 17.02）ng/L，t=13.198，P<0.01］than those in the good prognosis group. Additionally，the Acute Physiology and Chronic Health Evaluation Ⅱ（APACHEⅡ）score，Sequential Organ Failure Assessment（SOFA）score，PCT，and WBC were significantly higher in the poor prognosis group than those in the good prognosis group（P<0.05）. Logistic regression analysis identified serum YKL-40（OR=1.522），UCP2（OR=1.658），APACHEⅡscore（OR=1.885），SOFA score（OR=1.973），and PCT（OR=2.014）as factors influencing the prognosis of drug-resistant KP sepsis（P<0.05）. ROC curve analysis showed that the area under the curve（AUC）for serum YKL-40 in predicting the prognosis of drug-resistant KP sepsis was 0.774（95%CI：0.680-0.852）with a sensitivity of 71.05%；for serum UCP2，the AUC was 0.778（95%CI：0.683-0.855）with a sensitivity of 68.42%. The combined prediction of serum YKL-40 and UCP2 had a sensitivity of 89.47% and an AUC of 0.899（95%CI：0.822-0.950），which was significantly higher than the AUC for serum YKL-40 alone（Z=2.297，P=0.022）or UCP2 alone（Z=2.152，P=0.031）. Conclusion Serum levels of YKL- 40 and UCP2 are elevated in patients with drug-resistant KP sepsis，and their combined use has a high predictive value for 28-day prognosis of drug-resistant KP sepsis.