Background: To investigate directional deviations between pilot holes and final pedicle screw trajectories in freehand placement and analyze risk factors for misplacement. While pedicle screws are widely used in thoracolumbosacral surgery, directional deviations between pilot holes and final screw trajectories remain understudied as potential risk factors for misplacement. Methods: Thirty-three patients undergoing posterior fixation were prospectively enrolled. Inertial measurement units (IMUs) tracked the spatial positions of pedicle finders and screwdrivers via custom software. Surgeons (n = 6) were stratified into senior, middle, and junior groups. Analyzed variables included the use of tapping, surgeon experience, spinal deformity status, screw tip morphology, and surgical parameters. Results: Among 198 implanted screws (6.00 ± 2.88/patient), all exhibited trajectory deviations (8.12° ± 3.47°). Tapping significantly reduced deviations (7.23° ± 3.23° vs. 8.87° ± 3.31°, p < 0.01). Senior surgeons achieved smaller deviations (7.34° ± 3.33°) than the middle group (8.60° ± 3.51°, p = 0.039) and junior group (8.68° ± 3.49°, p = 0.022). Multivariate analysis confirmed tapping (p = 0.001) and senior experience (p = 0.023) as protective factors. No significant associations emerged for spinal deformity (8.43° ± 3.73° vs. 7.97° ± 3.35°, p = 0.377), screw tip type (cylindrical, 8.43° ± 3.26° vs. tapered, 8.07 ± 3.51°; p = 0.637), obesity, or surgical position parameters. Conclusions Freehand pedicle screw placement consistently produces trajectory deviations from pilot holes, and surgeon experience and tapping are modifiable protective factors. The IMU-based tracking system enables quantitative surgical motion analysis, suggesting its utility for training optimization and technique standardization.

Objective To investigate the influence of helical tomographic radiotherapy plans with different combinations of lead gate width,pitch and algorithms on threading effects.Methods A target model was established with a Cheese Phantom used as the simulated human body,then three lead gate widths(1.0,2.5,and 5.0 cm),six screw pitches(0.143,0.172,0.215,0.287,0.430,and 0.500)and two computational grids(Fine algorithm and Normal algorithm)were respectively combined for designing the helical tomography radiotherapy plans.The radiotherapy plans with a pitch of 0.143,0.172,0.215,0.287 or 0.430 were enrolled into an experimental group,and the plans with a pitch of 0.500 were divided into a control group.The dosimetric parameters including maximum dose(Dmax),minimum dose(Dmin)and mean dose(Dmean)of the target area PTV1 and PTV2 were evaluated by the dose volume histogram(DVH).The dose homogeneity index(HI)of the target area was calculated,and the single rotation time and total treatment time of each plan were recorded and counted.SPSS 27.0 software was used for statistical analysis.Results No significant threading effect appeared regardless of the pitch value when the lead gate width was 1.0 cm.The threading effects in the experimental group were weaker than those in the control group when the lead gate width was 2.5 or 5.0 cm.The threading effect gradually rose with the pitch increased when the lead gate width was 5.0 cm.The most significant difference was found between the threading effect in case of the screw pitch being 0.500 and that with the screw pitch being 0.143,with the differenes being statistically obvious(P<0.05).The lead gate width had significant effects on the Dmax,Dmin,Dmean and HI of PTV1 and PTV2.When the lead gate width was 5.0 cm,high HI value and uneven dose distribution were detected and lowered screw pitch weakened the threading effect.The single rotation time first remained constant and then increased with the screw pitch was enlarged,with the changing points occurring in case of the screw pitches of 0.287 and 0.430.With a certain lead gate width,the treatment time for plans was shortened with the decrease of the pitches in case of the pritches lower than 0.287,and tended to be constant after the screw pitches reached 0.287.The changes of the computational grid had no significant effects on the results of radiotherapy plans when the lead gate width and screw pitch were kept constant.Conclusion When designing a spiral tomotherapy plan with conventional doses,a lead gate width of 1.0 or 2.5 cm and a screw pitch of 0.287 or 0.430 should be selected in order to minimize the threading effect while ensuring the efficiency of plan implementation.[Chinese Medical Equipment Journal,2025,46(8):58-66]

Objective:To summarize the clinicopathological features, evolving trends in treatment and surgical approaches, and survival outcomes of patients who underwent D2 radical gastrectomy for gastric cancer in Shanxi Provincial Cancer Hospital over the past 11 years with the goal of providing a reference for the clinical practice of gastric cancer in this region.Methods:A retrospective observational study was conducted to analyze the clinicopathological data of patients who underwent D2 radical gastrectomy for pathologically confirmed gastric malignancy at the Department of Gastrointestinal Surgery, Shanxi Provincial Cancer Hospital from January, 2013 to December, 2023. Exclusion criteria consisted of: (1) residual gastric cancer or recurrent gastric cancer after surgery; (2) emergency gastric cancer resection due to bleeding, perforation, obstruction, or other causes; (3) comorbidity with other primary malignant tumors; (4) severe preoperative cardiopulmonary insufficiency or hepatic and renal insufficiency who cannot tolerate radical surgery; and (5) inconsistent main diagnosis information across the medical record system, pathological system, and gastric cancer-specific database. Patients were divided into three groups based on treatment methods: the surgery-only group, the perioperative chemotherapy group, and the adjuvant chemotherapy group. Endpoints included: (1) baseline patient characteristics; (2) trends in tumor location and pathological features; (3) evolution of treatment modalities; and (4) survival outcomes.Results:A total of 15,644 patients were included in the analysis, with 12,591 males and 3,053 females, the male-to-female gender ration was approximately 4∶1; the mean age was (61.2±9.5) years. The tumor sites were mainly concentrated in the esophagogastric junction (EGJ) (57.4%), followed by the antrum (25.9%). The incidence of EGJ cancer initially rose and then declined. However, gastric antrum tumors remained stable, and gastric body tumors showed a slow upward trend after 2020, accounting for 16.7%. In terms of pathological types, poorly differentiated carcinoma was the most prevalent, accounting for 55.9%, followed by moderately differentiated carcinoma (24.2%), mucinous adenocarcinoma (or signet ring cell carcinoma,14.1%), neuroendocrine carcinoma (4.8%), and well-differentiated carcinoma (0.9%). The proportion of poorly differentiated adenocarcinoma showed a significant upward trend overall as well, peaking at 65.6% in 2022 and decreasing to 57.5% in 2023. Mucinous adenocarcinoma (or signet ring cell carcinoma) exhibited fluctuations with a first increase followed by a decrease: it peaked at 17.3% in 2018, dropped sharply to 8.4% in 2022, and rose back to 13.8% in 2023. The proportions of well-differentiated adenocarcinoma, moderately differentiated adenocarcinoma, and neuroendocrine tumors remained stable year by year. In terms of pathological staging, the overall proportions of gastric cancer at Stage 0, Stage I, Stage II, Stage III, and Stage IVa were 0.5%, 17.3%, 25.1%, 54.9%, and 2.3%, respectively. For Stage III, its proportion was 74.6% in 2013, which decreased to 46.4% by 2023. Stages I and II gastric cancer showed an upward trend, with their proportions rising from 10.2% and 12.1% in 2013 to nearly 21.0% and 29.6% in 2023, respectively. Between 2013 and 2023, the proportion of patients who received surgery alone continued to decrease, with this proportion dropping to 34.7% in 2023. In contrast, the number of patients who received adjuvant chemotherapy increased year by year, reaching 54.2% in 2023. Since 2017, the application of perioperative chemotherapy has gradually increased, rising to 11.1% in 2023. Immunotherapy showed an almost synchronous growth trend with perioperative chemotherapy. However, targeted therapy exhibited a downward trend after a period of growth. There were 10,704 cases of open surgery (68.4%), 4,744 cases of laparoscopic surgery (30.3%), and 193 cases of transthoracic surgery (1.2%). Pathological margin positivity was observed in 443 cases (2.8%), and the volume of gastric cancer surgeries gradually increased, peaked in 2021 before subsequently decreasing gradually. However, the volume of laparoscopic surgeries did not decrease; instead, it showed an upward trend. The main resection method for EGJ tumors was total gastrectomy, accounting for 78.5% of the total, followed by proximal gastrectomy, which accounted for 21.5%. After total gastrectomy, esophagojejunal Roux-en-Y anastomosis was the primary anastomotic method, and for proximal gastrectomy, the main anastomotic method was esophagogastric anastomosis, which accounted for 68.0% of the total. For distal gastrectomy, Billroth II anastomosis was the most common anastomotic technique, accounting for 92.7% of these procedures. The overall incidence of postoperative complications was 14.5% (2,264/15,644), among which the incidence of severe complications (grades III-IV) was 4.5% (706/15,644). The entire cohort was followed up with for (47.1±36.8) months, and the 1-year, 3-year, and 5-year overall survival rates were 86.4%, 65.9%, and 58.1%, respectively. For patients with stage 0, I, II, III, and IV gastric adenocarcinoma, the 1-year overall survival rates were 95.7%, 98.0%, 89.4%, 81.0%, and 49.1%, respectively; the 3-year overall survival rates were 92.1%, 94.6%, 81.9%, 51.4%, and 14.7%, respectively; and the 5-year overall survival rates were 89.4%, 91.7%, 75.1%, 41.5%, and 10.0%, respectively. For patients with stage I, II, III, and IV gastric neuroendocrine carcinoma, the 1-year overall survival rates were 96.7%, 91.1%, 73.8%, and 52.6%, respectively; the 3-year overall survival rates were 87.2%, 69.6%, 46.1%, and 32.1%, respectively; and the 5-year overall survival rates were 87.2%, 62.2%, 36.7%, and 32.1%, respectively.Conclusions:Gastric cancer in Shanxi Province is characterized by a male predominance, a high prevalence of tumors at the esophagogastric junction, a large proportion of poorly differentiated adenocarcinoma, and presentation at advanced stages (predominantly Stage III). The detection rate of early gastric cancer has been increasing year by year, the volume of laparoscopic surgeries has been on the rise annually, and the treatment model has shifted from single surgery to comprehensive treatment.

This consensus was developed by the Orthodontic Society of the Chinese Stomatological Association to provide a systematic, scientific, and practical guideline for informed consent in orthodontic care. Orthodontic treatment is typically lengthy, highly individualized, and involves multiple factors such as growth and development, occlusal function, and facial esthetics. Rapid technological advances and diverse risk profiles make the traditional reliance on orthodontist experience or institutional templates insufficient to ensure patients′ full understanding and autonomous decision-making. To address this, the expert panel conducted extensive reviews of domestic and international guidelines, analyzed representative dispute cases, and performed multicenter patient-clinician surveys. Using a multi-round Delphi method, the group established a standardized informed consent framework covering the initial consultation, treatment, and retention phases. The consensus emphasizes that informed consent is not only a fundamental legal and ethical requirement but also a key step in building trust, improving patient compliance, and enhancing treatment satisfaction. Orthodontists should clearly and comprehensively explain treatment plans, potential risks, uncertainties, and associated costs, while respecting the autonomy of patients or guardians, and maintain continuous communication and dynamic evaluation throughout the treatment process. The release of this consensus provides unified and authoritative guidance for clinical orthodontics, helping to standardize informed consent, enhance its transparency, safeguard patient rights, reduce medical risks, and promote high-quality, sustainable development of orthodontic practice.

Objective:To explore the correlation between serum ferritin(SF)levels and the efficacy of platelet transfusion in patients with malignant hematological diseases.Methods:Patients with malignant hematological diseases who received repeated transfusions of apheresis platelets in Department of Hematology of Aerospace Center Hospital in 2023 were selected.The platelet corrected count increment(CCI)was used to evaluate the efficacy of platelet transfusion.The correlations between sex,age,disease type,transplantation history,red blood cell transfusion history,and SF level and the efficacy of platelet transfusion were analyzed.Results:A total of 87 patients were included,with a cumulative 326 person-times platelet transfusions.As suggested by one-way analysis of variance,compared with the patients in the age groups of 24-45 years old and 46-66 years old,the patients in the age group of 2-23 years old had a better efficacy of platelet transfusion(P=0.004,P=0.004).There was no significant difference in the efficacy of platelet transfusion between the patients in the age group of 24-45 years old and those in the age group of 46-66 years old(P=0.876).Compared with the patients who had a history of red blood cell transfusion within 3 days,the patients without a history of red blood cell transfusion within 3 days had a better efficacy of platelet transfusion(P＜0.001).Compared with the groups with SF levels of 1.44-2.78 ng/L and＞2.78 ng/L,the group with SF levels＜1.44 ng/L had a better efficacy of platelet transfusion(P=0.028,P＜0.001).Compared with the group with SF levels＞2.78 ng/L,the group with SF levels of 1.44-2.78 ng/L had a better efficacy of platelet transfusion(P=0.001).After adjusting for age and the history of red blood cell transfusion,the transfusion efficacy of the group with SF levels＜1.44 ng/L was better than that of the groups with SF levels of 1.44-2.78 ng/L and＞2.78 ng/L(P=0.021,P＜0.001);Compared with the group with SF levels＞2.78 ng/L,the group with SF levels of 1.44-2.78 ng/L had a better efficacy of platelet transfusion(P=0.001).Both univariate and multivariate linear regression models showed that SF levels were negatively correlated with the efficacy of platelet transfusion(P＜0.001).Conclusion:There is a negative correlation between SF levels and the efficacy of platelet transfusion in patients with malignant hematological diseases.Detection of SF levels may provide guidance for predicting the efficacy of platelet transfusion.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.

Objective:To evaluate the diagnostic value of native T1 mapping in differentiating Oxford classification (MEST-C) scores in patients with IgA nephropathy.Methods:In this prospective study, patients who underwent both T1 mapping and renal biopsy at the First Medical Center of the Chinese PLA General Hospital between April 2023 and October 2024 were consecutively enrolled. Two radiologists, blinded to clinical and pathological information, measured renal T1 mapping parameters, including cortical T1 (cT1), medullary T1 (mT1), the corticomedullary difference (ΔT1), and the corticomedullary ratio (T1 ratio). Clinical and renal biopsy data based on the Oxford classification from patients with IgA nephropathy were collected. The Oxford classification includes five indicators: Mesangial hypercellularity (M), Endocapillary hypercellularity (E), Segmental glomerulosclerosis or adhesion (S), Tubular atrophy/interstitial fibrosis (T), and Cellular or fibrocellular crescents (C). Spearman correlation analysis was applied to evaluate the associations between MEST-C scores and T1 parameters. The diagnostic performance of T1 parameters for discriminating among scores of the Oxford classification was analyzed using the receiver operating characteristic (ROC) curve.Results:A total of 124 patients with IgA nephropathy were included in this study [66 males, 58 females; age 19-70 years, 39 (30, 51) years]. Except for the E indicator, M, S, T, and C were significantly correlated with renal T1 values ( ρ=0.177-0.414, all P<0.05). cT1 showed the best diagnostic efficacy for the S score, with an area under the curve (AUC) of 0.798, a sensitivity of 68.7%, and a specificity of 88.0%. The best T1 parameter for differentiating the T score was the T1 ratio, with an AUC of 0.687, a sensitivity of 57.9%, and a specificity of 79.1%. Conclusion:Native T1 mapping can be used for the non-invasive assessment of the S and T scores in the Oxford classification of patients with IgA nephropathy.

BACKGROUND:Our previous studies found that decreased expression of connexin 43 and its Ser368 phosphorylation after myocardial hypothermic ischemia-reperfusion was closely associated with decreased cardiac conduction velocity and reperfusion arrhythmia.OBJECTIVE:To observe the effect of changes in membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2 and collagen type Ⅳ on the expression of connexin 43 and its Ser368 phosphorylation and electrical conduction in the myocardial extracellular matrix after hypothermic ischemia-reperfusion.METHODS:Sixteen Langendorff extracorporeal cardiac perfusion models were successfully established from SD rats and randomly divided into a control group(n=8)and a hypothermic ischemia-reperfusion group(n=8).The control group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes and then continued to be perfused with 37 ℃ Krebs-Henseleit solution for 90 minutes.The hypothermic ischemia-reperfusion group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes,and then the heart was arrested for 60 minutes by injection of 4 ℃ Thomas solution.During the cardiac arrest,the periphery was protected by 4 ℃ Krebs-Henseleit solution.Half-volume 4 ℃ Thomas solution was reperfused 30 minutes after the arrest.After stopping the arrest,the heart was reperfused with 37 ℃ Krebs-Henseleit solution for 30 minutes.The occurrence of arrhythmias,rebeating time,and the duration of arrhythmias were recorded from the immediate time point to the end of the reperfusion period.Conduction velocity,absolute inhomogeneity,and inhomogeneity index were measured using the Mapping Lab multi-channel electrophysiological mapping system at the time of balanced perfusion for 15 minutes(T1),reperfusion for 15 minutes/continuous perfusion for 90 minutes(T2),and reperfusion for 30 minutes/continuous perfusion for 105 minutes(T3).The relative expression levels of membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2,collagen type Ⅳ,connexin 43,and its Ser368 phosphorylation in ventricular tissue were detected by western blot assay.RESULTS AND CONCLUSION:(1)No arrhythmia occurred in the control group.There were six cases of arrhythmia in the hypothermic ischemia-reperfusion group during reperfusion.Rebeating time and duration of arrhythmias were(25.38+12.02)and(158.67±67.68)seconds,respectively.(2)The conduction sochronal diagrams at T1,T2,and T3 in the control group were uniform and regular in direction,and the conduction velocity at T2 and T3 was not different from that at T1(P＞0.05).The conduction isochronal diagrams at T2 and T3 in the hypothermic ischemia-reperfusion group were uneven and irregular in direction,and the conduction velocity was slower than that at T1(P＜0.01).The conduction velocity at T2 and T3 in the hypothermic ischemia-reperfusion group was slower than that in the control group(P＜0.01).Conduction dispersion was greater in the hypothermic ischemia-reperfusion group than that in the control group at T2 and T3(P＜0.05).(3)Compared with the control group,the protein expressions of membrane-type matrix metalloproteinase 2 and matrix metalloproteinase 2 in the hypothermic ischemia-reperfusion group were increased(P＜0.05 or P＜0.01),and the protein expression levels of type Ⅳ collagen,connexin 43 and its Ser368 phosphorylation were decreased(P＜0.05 or P＜0.01).(4)The results indicate that after hypothermic ischemia-reperfusion,myocardial extracellular matrix remodeling may mediate the downregulation of myocardial connexin 43 and its Ser368 phosphorylation,slowed conduction velocity and increased conduction dispersion,thereby increasing the risk of arrhythmia.

BACKGROUND:Our previous studies found that decreased expression of connexin 43 and its Ser368 phosphorylation after myocardial hypothermic ischemia-reperfusion was closely associated with decreased cardiac conduction velocity and reperfusion arrhythmia.OBJECTIVE:To observe the effect of changes in membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2 and collagen type Ⅳ on the expression of connexin 43 and its Ser368 phosphorylation and electrical conduction in the myocardial extracellular matrix after hypothermic ischemia-reperfusion.METHODS:Sixteen Langendorff extracorporeal cardiac perfusion models were successfully established from SD rats and randomly divided into a control group(n=8)and a hypothermic ischemia-reperfusion group(n=8).The control group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes and then continued to be perfused with 37 ℃ Krebs-Henseleit solution for 90 minutes.The hypothermic ischemia-reperfusion group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes,and then the heart was arrested for 60 minutes by injection of 4 ℃ Thomas solution.During the cardiac arrest,the periphery was protected by 4 ℃ Krebs-Henseleit solution.Half-volume 4 ℃ Thomas solution was reperfused 30 minutes after the arrest.After stopping the arrest,the heart was reperfused with 37 ℃ Krebs-Henseleit solution for 30 minutes.The occurrence of arrhythmias,rebeating time,and the duration of arrhythmias were recorded from the immediate time point to the end of the reperfusion period.Conduction velocity,absolute inhomogeneity,and inhomogeneity index were measured using the Mapping Lab multi-channel electrophysiological mapping system at the time of balanced perfusion for 15 minutes(T1),reperfusion for 15 minutes/continuous perfusion for 90 minutes(T2),and reperfusion for 30 minutes/continuous perfusion for 105 minutes(T3).The relative expression levels of membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2,collagen type Ⅳ,connexin 43,and its Ser368 phosphorylation in ventricular tissue were detected by western blot assay.RESULTS AND CONCLUSION:(1)No arrhythmia occurred in the control group.There were six cases of arrhythmia in the hypothermic ischemia-reperfusion group during reperfusion.Rebeating time and duration of arrhythmias were(25.38+12.02)and(158.67±67.68)seconds,respectively.(2)The conduction sochronal diagrams at T1,T2,and T3 in the control group were uniform and regular in direction,and the conduction velocity at T2 and T3 was not different from that at T1(P＞0.05).The conduction isochronal diagrams at T2 and T3 in the hypothermic ischemia-reperfusion group were uneven and irregular in direction,and the conduction velocity was slower than that at T1(P＜0.01).The conduction velocity at T2 and T3 in the hypothermic ischemia-reperfusion group was slower than that in the control group(P＜0.01).Conduction dispersion was greater in the hypothermic ischemia-reperfusion group than that in the control group at T2 and T3(P＜0.05).(3)Compared with the control group,the protein expressions of membrane-type matrix metalloproteinase 2 and matrix metalloproteinase 2 in the hypothermic ischemia-reperfusion group were increased(P＜0.05 or P＜0.01),and the protein expression levels of type Ⅳ collagen,connexin 43 and its Ser368 phosphorylation were decreased(P＜0.05 or P＜0.01).(4)The results indicate that after hypothermic ischemia-reperfusion,myocardial extracellular matrix remodeling may mediate the downregulation of myocardial connexin 43 and its Ser368 phosphorylation,slowed conduction velocity and increased conduction dispersion,thereby increasing the risk of arrhythmia.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.