ObjectiveObesity, a global chronic metabolic disease, is closely associated with disruptions in lipid metabolism and gut microbiota. Current intervention strategies still have limitations in terms of safety and microecological regulation, necessitating the exploration of novel natural regulatory approaches. Based on the early pathological characteristics of obesity, this study innovatively employs a rectal delivery method alongside a high-fat diet (HFD)-induced obesity model to systematically evaluate the inhibitory effects, safety, and gut microbiota regulation mechanisms of leek-derived and konjac-derived extracellular vesicles on obesity development. By simulating early clinical intervention scenarios, this study aims to explore the preventive potential of plant-derived extracellular vesicles during the initial stages of obesity onset. MethodsExtracellular vesicles from leek and konjac were isolated using ultracentrifugation combined with density gradient centrifugation. Their nanoscale properties were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Male C57BL/6J mice were randomly divided into four groups: normal control (NC), high-fat diet (HFD), leek-derived extracellular vesicles (LEVs), and konjac-derived extracellular vesicles (KEVs). Beginning simultaneously with HFD feeding, mice in the intervention groups received 20 g/L vesicles rectally every 3 d for 4 weeks. Body mass and body composition were monitored throughout. At endpoint, mouse serum, adipose tissue, and colonic contents were collected. Serum biochemical indices (lipid profile, liver and kidney function, cardiac markers) were assessed to evaluate safety and metabolic efficacy, while 16S rRNA sequencing was employed to analyze gut microbial structure and diversity. ResultsDLS, NTA, and TEM confirmed that both LEVs and KEVs exhibited typical cup-shaped nanostructures with average particle sizes of approximately 284 nm and 223 nm, respectively. LEVs and KEVs treatment significantly suppressed HFD-induced weight gain and elevation of body-fat percentage (P<0.05), and reduced accumulation of abdominal white and epididymal adipose tissue. Serological analyses showed that both vesicles lowered total cholesterol, triglycerides and LDL-cholesterol, and ameliorated liver enzyme profiles (ALT, AST), demonstrating lipid-metabolic regulation and hepatoprotective effects. No hepatic, renal or cardiac dysfunction was observed, indicating favorable safety. Gut microbiota analyses revealed that vesicle intervention partially restored HFD-depleted microbial diversity and reshaped community structure. Notably, LEVs markedly increased the relative abundance of the beneficial taxon Lachnospiraceae at the family level, which is known for producing short-chain fatty acids and enhancing intestinal barrier function. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional prediction suggested that LEVs and KEVs modulated gut microbial functions through distinct mechanisms: LEVs downregulated pathways related to ribosomes and DNA replication while enhancing xenobiotic degradation, whereas KEVs tended to upregulate energy metabolism and protein synthesis toward healthy levels. ConclusionRectally administered LEVs and KEVs exhibit excellent safety and pronounced metabolic benefits during the early phase of obesity, suppressing weight gain, correcting lipid dysregulation, and exerting effects via modulation of gut microbial composition and function. This study provides systematic experimental evidence supporting plant-derived exosome-like vesicles as an early intervention strategy against obesity.

ObjectiveObesity, a global chronic metabolic disease, is closely associated with disruptions in lipid metabolism and gut microbiota. Current intervention strategies still have limitations in terms of safety and microecological regulation, necessitating the exploration of novel natural regulatory approaches. Based on the early pathological characteristics of obesity, this study innovatively employs a rectal delivery method alongside a high-fat diet (HFD)-induced obesity model to systematically evaluate the inhibitory effects, safety, and gut microbiota regulation mechanisms of leek-derived and konjac-derived extracellular vesicles on obesity development. By simulating early clinical intervention scenarios, this study aims to explore the preventive potential of plant-derived extracellular vesicles during the initial stages of obesity onset. MethodsExtracellular vesicles from leek and konjac were isolated using ultracentrifugation combined with density gradient centrifugation. Their nanoscale properties were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Male C57BL/6J mice were randomly divided into four groups: normal control (NC), high-fat diet (HFD), leek-derived extracellular vesicles (LEVs), and konjac-derived extracellular vesicles (KEVs). Beginning simultaneously with HFD feeding, mice in the intervention groups received 20 g/L vesicles rectally every 3 d for 4 weeks. Body mass and body composition were monitored throughout. At endpoint, mouse serum, adipose tissue, and colonic contents were collected. Serum biochemical indices (lipid profile, liver and kidney function, cardiac markers) were assessed to evaluate safety and metabolic efficacy, while 16S rRNA sequencing was employed to analyze gut microbial structure and diversity. ResultsDLS, NTA, and TEM confirmed that both LEVs and KEVs exhibited typical cup-shaped nanostructures with average particle sizes of approximately 284 nm and 223 nm, respectively. LEVs and KEVs treatment significantly suppressed HFD-induced weight gain and elevation of body-fat percentage (P<0.05), and reduced accumulation of abdominal white and epididymal adipose tissue. Serological analyses showed that both vesicles lowered total cholesterol, triglycerides and LDL-cholesterol, and ameliorated liver enzyme profiles (ALT, AST), demonstrating lipid-metabolic regulation and hepatoprotective effects. No hepatic, renal or cardiac dysfunction was observed, indicating favorable safety. Gut microbiota analyses revealed that vesicle intervention partially restored HFD-depleted microbial diversity and reshaped community structure. Notably, LEVs markedly increased the relative abundance of the beneficial taxon Lachnospiraceae at the family level, which is known for producing short-chain fatty acids and enhancing intestinal barrier function. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional prediction suggested that LEVs and KEVs modulated gut microbial functions through distinct mechanisms: LEVs downregulated pathways related to ribosomes and DNA replication while enhancing xenobiotic degradation, whereas KEVs tended to upregulate energy metabolism and protein synthesis toward healthy levels. ConclusionRectally administered LEVs and KEVs exhibit excellent safety and pronounced metabolic benefits during the early phase of obesity, suppressing weight gain, correcting lipid dysregulation, and exerting effects via modulation of gut microbial composition and function. This study provides systematic experimental evidence supporting plant-derived exosome-like vesicles as an early intervention strategy against obesity.

Objective To investigate the regulation of synaptic plasticity by cannabinoid receptor 1(CB1R)and its effects on autism spectrum disorder(ASD)-like behavior.Methods CB1R-knockout(KO)mice and valproic acid(VPA)-induced ASD model mice(VPA mice)were used as study subjects.Behavioral experiments were used to assess the effects of CB1R on ASD-like behavior in mice,neuronal structural integrity and dendritic density were detected by microtubule-associated protein 2(MAP2)staining experiments,and the expression of synapse-associated proteins was detected by Western blot,to assess the effects of CB1R on synaptic plasticity.Results Behavioral result showed that VPA mice demonstrated significant ASD-like behavior,while CB1R-/-mice spent a significantly smaller proportion of residence time in the central region of the open field(P＜0.0001),showed significant increases in the number of marbles buried and self-grooming time(P＜0.01),significantly less time spent socializing with unfamiliar mice 2 and exploring unfamiliar objects(P＜0.001),and significantly more time exploring old objects(P＜0.05).The relative dwelling time was significantly reduced in CB1R+/-mice(P＜0.001),and the number of marbles buried and self-grooming time were significantly increased(P＜0.05).Synaptic plasticity assays revealed significant synaptic plasticity impairment in VPA mice.Hippocampal MAP2-positive neuron densities were significantly reduced in CB1R-/-and CB1R+/-mice,and expression levels of synapsin-1 were significantly increased(P＜0.05).Conclusions CB1R KO leads to ASD-like behavior such as anxiety and repetitive stereotyped behavior,social and cognitive impairments,as well as neuronal damage,dendritic dysplasia and disrupted synaptic protein expression in mice,suggesting that CB1R is involved in regulating synaptic plasticity as a pathological mechanism for the development of ASD-like behavior.

Aim To investigate the effect of high-fat diet on the tight junction function injury of Sertoli cells through the NF-κB/NLRP3 signaling pathway in mice and to explore the underlying mechanism.Methods Male C57BL/6J mice were fed with high-fat or normal diet for five months.The body and gonadal organ weight of mice were measured,and their indices were calculated.The sperm concentration,the sperm viabili-ty,the testicular histomorphology and the expression levels of tight junction proteins ZO-1,Occludin and Claudin-11 were measured.TM4 cells were treated with palmitic acid(PA)for 24 h.Cell viability was detected by CCK-8 method.Then,TM4 cells were di-vided into different groups treated with PA(0,50,100,200 and 300 μmnol·L-1),and the expression lev-els of tight junction proteins ZO-1,Occludin and Clau-din-11 were detected by Western blot.The tight junc-tion permeability of TM4 cells were detected by transepithelial electrical resistance(TEER)and FITC-dextran.The expression levels of mRNA and proteins for the NF-κB/NLRP3 pathway-related factors were de-tected by RT-qPCR and Western blot.Results The results from animal experiments showed that high-fat diet increased body weight and seminal vesicle weight of mice,and decreased testicular index,epididymal in-dex,sperm concentration and sperm motility of mice.High-fat diet also caused testicular tissue structure damage and down-regulated the expression levels of tight junction proteins ZO-1 and Occludin,without af-fecting the expression of Claudin-11.In vitro,PA sig-nificantly down-regulated the expression levels of ZO-1,Occludin and Claudin-11 in TM4 cells,increased the cell permeability,as well as up-regulated the mRNA and protein expression levels of NLRP3/NF-κB signa-ling pathway-related factors in TM4 cells.Conclusions High-fat diet can impair the function of tight junction of testicualr Sertoli cells,and the machanism may be related to the activation of the NF-κB/NLRP3 signaling pathway,resulting in Sertoli cell inflammation in mice.

Objective To investigate the mechanism by which long non-coding RNA(lncRNA)AI662270 regulates insulin resistance in adipocytes in aging mice.Methods(1)Twenty male C57BL/6 mice were randomly divided into youth(4-month-old)group and aged(18-month-old)group(n=10).Mice in youth group were raised to 4 months of age and euthanized by orbital exsanguination under urethane anesthesia,while aged mice were euthanized at 18 months using the same sacrifice method.Epididymal white adipose tissue(eWAT)and liver tissue were rapidly dissected.Western blotting was employed to detect the protein expression levels of tumor suppressor gene 1(p16ink4a)and cyclin-dependent kinase inhibitor p21(p21kip1),RT-qPCR was used to measure the expression of 4 differentially expressed lncRNAs(C4a,AI662270,BATE1 and Gm29719).Mouse embryonic fibroblasts(3T3-L1)were cultured and divided into a normal control group(no treatment after induced differentiation into mature adipocytes)and a senescence model group[doxorubicin(ADR)-treated group;0.2 μmol/L ADR was used to induce senescent adipocytes].β-galactosidase staining was performed to assess adipocyte senescence.RT-qPCR was applied to evaluate the expression of AI662270 and senescence markers(p16ink4a,p21kip1,p53),while Western blotting was utilized to detect the expression levels of phosphorylated H2A histone family member X(γ-H2AX),p16ink4a,and p21kip1 proteins.(2)Hexokinase method was adopted to measure glucose content in mouse serum and 3T3-L1 adipocyte culture medium.RT-qPCR was performed to analyze mRNA expression levels of insulin sensitivity-related gene protein kinase B(Akt),insulin receptor substrate 1(IRS1),phosphatidylinositol 3 kinase(PI3K)and glucose transporter 4(GLUT4)in mouse eWAT and adipocytes.Western blotting was conducted to determine the protein expression levels of IRS 1,PI3K,Akt,and p-Akt.(3)Spearman correlation analysis was applied to examine the correlation between AI662270 expression levels and IRS1/PI3K mRNA expression levels.A low-expression model of AI662270 in senescent adipocytes was constructed,and RT-qPCR was used to verify the knockdown efficiency.Hexokinase method was employed to assess glucose content in the cell culture medium of senescent adipocytes after AI662270 knockdown.RT-qPCR was performed to measure the mRNA expressions of Akt,IRS1,IRS2,and PI3K,while Western blotting was utilized to detect the expressions levels of Akt and p-Akt proteins.(4)Bioinformatics analysis was performed to predict downstream target genes of AI662270 and their binding sites.RT-qPCR and Western blotting were subsequently applied to validate the expression of these downstream target genes following AI662270 knockdown.Results(1)Compared with youth group,the protein expression levels of p16ink4a and p21kip1 in eWAT of aged mice were significantly increased(P＜0.05).Additionally,the expression levels of C4a,AI662270,BATE1,and Gm29719 in both eWAT and liver tissues were significantly increased in aged group(P＜0.05).β-galactosidase staining revealed enhanced blue-green coloration and enlarged,flattened cellular morphology in ADR-treated senescent adipocytes compared with normal control group.Compared with normal control group,ADR-treated senescent adipocytes significantly increased the mRNA expression levels of AI662270,p16ink4a,and p21kip1,and significantly elevated protein expression levels of γ-H2AX,p16ink4a,and p21kip1(P＜0.05).(2)Serum glucose content was significantly higher in aged group mice compared with youth group(P＜0.01),and glucose content in the adipocyte culture medium in ADR group was significantly increased(P＜0.05).The expression levels of IRS1 and PI3K in eWAT in aged group were significantly reduced compared with youth group(P＜0.01).Compared with normal control group,the expression levels of IRS 1 and PI3K in adipocytes in ADR-treated group were also significantly reduced(P＜0.05).(3)Spearman correlation analysis demonstrated that the expression level of AI662270 was negatively correlated with the mRNA expression levels of IRS1 and PI3K(P＜0.05).RT-qPCR showed that AI662270 expression level was significantly reduced in the siAI662270-transfected senescent adipocytes compared with siNC group(P＜0.05),indicating the low expression model of aged adipocytes AI662270 was successfully constructed.Hexokinase assay results showed that glucose content in the cell culture medium was significantly reduced after the AI662270 was knocked down by senescent adipocytes(P＜0.05).Furthermore,the mRNA expression levels of IRS1,IRS2 and PI3K(P＜0.05)and the p-Akt/Akt ratio in senescent adipocytes was significantly increased after knockdown of AI662270(P＜0.01).(4)Bioinformatics analysis predicted miR-3073b-3p as a downstream target gene of AI662270,and heme oxygenase 1(Hmox1)was identified as a target molecule of miR-3073b-3p.The expression level of miR-3073b-3p in senescent adipocytes in siAI662270 group was significantly increased,while the mRNA and protein expression level of Hmox1 were significantly decreased compared with siNC group(P＜0.01).Conclusions Aging significantly increases the expression of AI662270 in eWAT of mice,and the expression of AI662270 was negatively correlated with insulin sensitivity.AI662270 knockdown can reduce glucose content in senescent adipocyte culture medium,upregulate the expression of IRS1 and PI3K,and increase insulin sensitivity in senescent adipocytes,which may be mediated through the AI662270/miR-3073b-3p/Hmox1 pathway.

Objective To investigate the regulatory effect and molecular mechanism of circ_0044556 on the malignant biological behavior of triple negative breast cancer(TNBC)cells by targeting the miR-338-3p/bromodomain-containing protein 4(BRD4)axis.Methods The TargetScan online website was used to predict the binding sites of circ_0044556 with miR-338-3p and miR-338-3p with BRD4.Dual-luciferase reporter gene assays were performed to determine the relationship among circ_0044556,miR-338-3p,and BRD4 in MDA-MB-231 cells.Quantitative real-time PCR(qRT-PCR)and Western blotting were employed to detect the expression of circ_0044556,miR-338-3p,and BRD4 protein in human TNBC cell line MDA-MB-231 and human normal breast epithelial cells MCF-10A.MDA-MB-231 cells were divided into NC group,si-NC group(transfected with si-NC),si-circ_0044556 group(transfected with si-circ_0044556),si-circ_0044556+inhibitor NC group(transfected with si-circ_0044556 and inhibitor NC),and si-circ_0044556+miR-338-3p inhibitor group(transfected with si-circ_0044556 andmiR-338-3p inhibitor).qRT-PCR was applied to detect the expression of circ_0044556 and miR-338-3p;Western blotting was used to detect the expression of BRD4,E-cadherin,N-cadherin and Vimentin;the CCK-8 assay was applied to detect cell proliferation;flow cytometry was applied to detect cell apoptosis;and Transwell assays were used to detect cell invasion and migration.Thirty nude mice were randomly divided into NC group(tail vein injection of normal saline),si-NC group(tail vein injection of LV-NC),si-circ_0044556 group(tail vein injection of LV-circ_0044556),si-circ_0044556+inhibitor NC group(tail vein injection of LV-circ_0044556 and antiagomir NC),and si-circ_0044556+miR-338-3p inhibitor group(tail vein injection of LV-circ_0044556 and antiagomir miR-338-3p),with 6 mice per group.A xenograft tumor model was constructed by subcutaneous injection of MDA-MB-231 cells into nude mice,and tumor volume and weight were measured.Results TargetScan prediction results showed that the downstream miRNA of circ_0044556 was miR-338-3p,and the downstream target gene of miR-338-3p might be BRD4.Compared with transfecting mimic NC,transfection with miR-338-3p mimic significantly reduced the luciferase activities of WT-circ_0044556(0.34±0.03 vs.1.00±0.15,P<0.05)and WT-BRD4(0.41±0.05 vs.1.05±0.13,P<0.05)in MDA-MB-231 cells.Compared with MCF-10A cells,the expression levels of circ_0044556 and BRD4 protein in MDA-MB-231 cells were significantly increased,while the expression level of miR-338-3p was significantly decreased(P<0.05).Compared with NC group and si-NC group,the expression levels of circ_0044556,the protein expression levels of BRD4,N-cadherin,and Vimentin,and the OD450 value in MDA-MB-231 cells of si-circ_0044556 group and si-circ_0044556+inhibitor NC group were significantly decreased(P<0.05),the number of migrated and invaded cells was significantly reduced(P<0.05),and the expression level of miR-338-3p,the protein expression level of E-cadherin,and the cell apoptosis rate in MDA-MB-231 cells were significantly increased(P<0.05);downregulation of miR-338-3p rescued the inhibitory effect of circ_0044556 knockdown on invasion,migration,and proliferation of MDA-MB-231 cells.Compared with NC group and si-NC group,the tumor volume and weight in si-circ_0044556 group and si-circ_0044556+inhibitor NC group were significantly decreased(P<0.05);compared with si-circ_0044556 group and si-circ_0044556+inhibitor NC group,the tumor volume and weight in si-circ_0044556+miR-338-3p inhibitor group were significantly increased(P<0.05).Conclusion circ_0044556 may promote the malignant biological behaviors of TNBC cells through the miR-338-3p/BRD4 axis.

Objective To report a case of tibial synovial sarcoma and review relevant literature to enhance understanding of this disease.Methods The clinical data of a patient with tibial synovial sarcoma treated at Kaifeng Central Hospital were retrospectively analyzed.A literature search was conducted in domestic and international databases,including China National Knowledge Infrastructure(CNKI),Wanfang Data,PubMed,Web of Science,and Embase,up to July 2024.Relevant literature was comprehensively reviewed to summarize the imaging and pathological characteristics,treatment,and prognosis of synovial sarcoma.Results A 29-year-old female patient was admitted with left lower extremity pain.X-ray examination revealed a proximal tibia space-occupying lesion suggestive of malignancy,and a mid-tibial space-occupying lesion considered benign.Contrast-enhanced computed tomography(CT)and plain magnetic resonance imaging(MRI)of the proximal tibial lesion also suggested malignancy.Ultrasound-guided biopsy of the proximal tibial tumor revealed a poorly differentiated malignant tumor.Immunohistochemistry results indicated monophasic synovial sarcoma,requiring genetic testing for definitive diagnosis.The patient underwent wide resection of the proximal left tibial malignancy with tumor-type artificial joint replacement,combined with curettage and bone cement filling for the left mid-tibial lesion under anesthesia.Postoperative pathology of space-occupying lesions in the proximal tibia confirmed monophasic synovial sarcoma,and fluorescence in situ hybridization(FISH)demonstrated a rupture of the synovial sarcoma translocation gene(SYT)(i.e.,SS18 positive).There was no recurrence or metastasis found in the patient during the reexamination 6 months after postoperative chemotherapy.As of July 2024,15 cases of genetically confirmed primary intraosseous synovial sarcoma have been reported internationally.Symptoms included pain and swelling,with a medical history of 1-2 years.The X-ray and CT findings showed osteolytic destruction with bone cortical discontinuity.In 13 cases,the intraosseous masses extended to the extraosseous area;in 2 cases,punctate calcifications were detected within the masses.Plain MRI scan showed iso-signal or hypo-signal on T1WI and hyper-signal,iso-signal,and hypo-signal on fat-suppressed T2WI,and enhanced MRI scan demonstrated heterogeneous enhancement.Pathological examination showed spindle-shaped cells under microscopy.Immunohistochemistry results showed positive epithelial membrane antigen(EMA),broad-spectrum cytokeratin(AE1/AE3),Ewing's sarcoma marker(CD99),and transducin-like enhancer of Split 1(TLE1).Twelve patients underwent surgical treatment;6 patients received adjuvant chemotherapy after surgery,of whom 4 developed local recurrence or distant metastasis at initial diagnosis,and 3 died during follow-up.Among the 6 patients who did not receive adjuvant chemotherapy,3 suffered from recurrence or distant metastasis.Conclusions Primary intraosseous synovial sarcoma is a rare malignant tumor with non-specific clinical manifestations.Imaging features typically include osteolytic destruction and intraosseous masses extending extraosseously,suggesting an intraosseous origin.Pathology and immunohistochemistry aid diagnosis,but definitive confirmation relies on further genetic testing.At present,the main treatment regimens for synovial sarcoma involve comprehensive therapies such as surgery and adjuvant chemotherapy,and the prognosis of patients is poor.

Aim To investigate the effect of high-fat diet on the tight junction function injury of Sertoli cells through the NF-κB/NLRP3 signaling pathway in mice and to explore the underlying mechanism.Methods Male C57BL/6J mice were fed with high-fat or normal diet for five months.The body and gonadal organ weight of mice were measured,and their indices were calculated.The sperm concentration,the sperm viabili-ty,the testicular histomorphology and the expression levels of tight junction proteins ZO-1,Occludin and Claudin-11 were measured.TM4 cells were treated with palmitic acid(PA)for 24 h.Cell viability was detected by CCK-8 method.Then,TM4 cells were di-vided into different groups treated with PA(0,50,100,200 and 300 μmnol·L-1),and the expression lev-els of tight junction proteins ZO-1,Occludin and Clau-din-11 were detected by Western blot.The tight junc-tion permeability of TM4 cells were detected by transepithelial electrical resistance(TEER)and FITC-dextran.The expression levels of mRNA and proteins for the NF-κB/NLRP3 pathway-related factors were de-tected by RT-qPCR and Western blot.Results The results from animal experiments showed that high-fat diet increased body weight and seminal vesicle weight of mice,and decreased testicular index,epididymal in-dex,sperm concentration and sperm motility of mice.High-fat diet also caused testicular tissue structure damage and down-regulated the expression levels of tight junction proteins ZO-1 and Occludin,without af-fecting the expression of Claudin-11.In vitro,PA sig-nificantly down-regulated the expression levels of ZO-1,Occludin and Claudin-11 in TM4 cells,increased the cell permeability,as well as up-regulated the mRNA and protein expression levels of NLRP3/NF-κB signa-ling pathway-related factors in TM4 cells.Conclusions High-fat diet can impair the function of tight junction of testicualr Sertoli cells,and the machanism may be related to the activation of the NF-κB/NLRP3 signaling pathway,resulting in Sertoli cell inflammation in mice.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.