1.The Role of FASN in Tumors and Its Targeted Therapy
Wen-Jing JIANG ; Ruo-Xi ZHANG ; Yu-Qing TAI ; Ya-Wen SUN ; Xi-Yu ZHANG ; Xiao LI
Progress in Biochemistry and Biophysics 2026;53(4):920-935
Malignant tumors represent a major threat to global health. Conventional anti-tumor pharmacotherapy often encounters challenges such as drug resistance, highlighting an urgent need for the development of novel therapeutic strategies. Fatty acid synthase (FASN), the key enzyme catalyzing de novo fatty acid synthesis, is subject to precise regulation at multiple levels, including transcriptional control, various post-translational modifications such as ubiquitination and phosphorylation, as well as modulation by diverse signaling pathways. Recent studies have revealed that FASN is aberrantly overexpressed in various malignant tumors and is closely associated with tumor progression and poor patient prognosis. FASN is a homodimer composed of seven functional domains that catalyzes the NADPH-dependent condensation of acetyl-CoA and malonyl-CoA to generate saturated fatty acids, primarily palmitic acid. Its stability is regulated by multiple ubiquitin ligases and deubiquitinating enzymes. Additionally, FASN is subject to upstream regulation via neural precursor cell-expressed developmentally downregulated 8 (Nedd8) modification and the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, thereby establishing a metabolic-signaling positive feedback loop. As a core executor of metabolic reprogramming, FASN promotes tumorigenesis through dual mechanisms. First, its fatty acid synthesis product, palmitate, participates in membrane phospholipid synthesis, lipid raft formation, and protein palmitoylation, thereby activating several key oncogenic signaling pathways, including PI3K/AKT/mTOR, wingless-type MMTV integration site family member (Wnt)/β‑catenin, and signal transducer and activator of transcription 3 (STAT3)/matrix metalloproteinase (MMP), leading to tumor development and progression. Second, FASN plays a pivotal role in modulating the anti-tumor functions of immune cells and remodeling the tumor immune microenvironment. Specifically, FASN enhances immune checkpoint inhibition by inducing programmed death-ligand 1 (PD-L1) palmitoylation, suppresses the activation of cytotoxic T lymphocytes and natural killer cells, and promotes the polarization of M2-type macrophages, consequently facilitating tumor immune evasion and malignant progression. Precisely due to its significant overexpression in tumor cells, its critical functional role, and its differential expression compared to normal cells, FASN has emerged as a highly promising target for anti-tumor drug development. Highly selective small-molecule inhibitors, notably represented by TVB-2640, have advanced to clinical trial stages and demonstrated favorable anti-tumor activity. Furthermore, the combination of FASN inhibitors with other chemotherapeutic agents or targeted drugs can overcome the limitations of monotherapy through synergistic effects or by resensitizing tumor cells to conventional drugs, achieving a “1+1>2” therapeutic outcome. With the advancement of modern traditional Chinese medicine (TCM), numerous active ingredients derived from TCM have been confirmed to exert anti-tumor effects by modulating FASN-related pathways. This integrated approach leverages the precision of Western medicine while simultaneously harnessing the holistic regulatory benefits of TCM to alleviate the side effects of radiotherapy and chemotherapy. Despite the promising prospects of FASN-targeted therapies, challenges remain, including tumor cell metabolic plasticity, tumor context-dependent responses, and heterogeneity. This review systematically summarizes the molecular structure, physiological functions, and mechanisms of FASN in tumorigenesis, as well as recent advances in targeted therapies. Future directions—including the precise identification of responsive patient populations using spatial transcriptomics, the development of novel combination regimens, and the active exploration of integrative strategies combining traditional Chinese and Western medicine—will facilitate the clinical translation of FASN-targeted therapies and open new avenues for improving the quality of life and prognosis of cancer patients.
2.Expert consensus on the application of artificial intelligence in lung cancer screening, diagnosis, and treatment (2026 edition)
Wenzhao ZHONG ; Haibo WANG ; Yi HU ; Hao ZHANG ; Jigang DAI ; Junqiang FAN ; Guibin QIAO ; Fan YANG ; Jian HU ; Fengwei TAN ; Xuening YANG ; Qiang PU ; Zihao CHEN ; Hongxia TIAN ; Lunxu LIU ; Hecheng LI ; Xiaolong YAN ; Zongyang YU ; Zhenbin QIU ; Yihua SUN ; Jing HU ; Yuhang SHI ; Zhifei GUO ; Peng ZHANG ; Kezhong CHEN ; Shugeng GAO ; Yilong WU
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(06):848-856
With the continuous deepening of the concept of precision diagnosis and treatment for lung cancer, how to achieve higher efficiency and accuracy in the screening, diagnosis, and treatment pathways in clinical practice has become an important issue that urgently needs to be overcome. The current clinical difficulty lies in the fact that despite continuous advancements in imaging and molecular diagnostic technologies, there are still limitations in manual efficiency and subjective experience when it comes to massive data analysis and multi-scale feature extraction. Artificial intelligence (AI), especially algorithm systems based on deep learning, is an innovative technology capable of deeply empowering medical big data. This method utilizes algorithms such as convolutional neural networks, combined with radiomics, pathomics, and multi-modal data fusion analysis, demonstrating immense potential in early precise detection and benign-malignant differentiation of pulmonary nodules, digital pathological subtype recognition and non-invasive prediction of driver genes, precise 3D surgical planning and automatic delineation of radiotherapy target volumes, as well as dynamic risk warning during follow-up. This innovative technology provides a brand-new solution for realizing intelligent and individualized lung cancer diagnosis and treatment models. This consensus, based on the latest evidence from evidence-based medicine and combined with the development trends in the AI field and real-world clinical needs, was ultimately formed by gathering the consensus opinions of multidisciplinary experts in radiology, pathology, thoracic surgery, and other fields. The main content covers the application specifications of AI in the three core scenarios of lung cancer screening, diagnosis, and treatment, the technical standards for data collection and algorithm validation, as well as the ethical and regulatory challenges faced at the current stage. It aims to clarify the applicable boundaries of AI as a clinical auxiliary decision support tool, providing scientific guidance and standardized exploration directions for peers currently engaged in or planning to carry out AI-assisted clinical diagnosis, treatment, and translation of lung cancer.
3.Tianxiang Pills Alleviates Myocardial Cell Pyroptosis in Rat Model of Myocardial Ischemia/Reperfusion Injury by Inhibiting Oxidative Stress via ROS/Caspase-1/GSDMD Signaling Pathway
Fei ZENG ; Hao HUANG ; Yu CAO ; Yaoming XI ; Jing LUO
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(18):143-150
ObjectiveTo investigate the mechanism by which Tianxiang pills (TXP) alleviates myocardial cell pyroptosis in the rat model of myocardial ischemia/reperfusion (I/R) injury through modulating the reactive oxygen species (ROS)/cysteinyl aspartate-specific proteinase-1 (Caspase-1)/gasdermin D (GSDMD) signaling pathway. MethodsA total of 54 SPF-grade adult male Sprague-Dawley rats were randomized into six groups (n=9): sham (thoracotomy only without ligation), I/R (left anterior descending coronary artery ligation for 30 min followed by reperfusion), NAC (positive control, N-acetylcysteine, 150 mg·kg-1, by gavage), low-dose Tianxiang pills (TXP-L, 2.5 g·kg-1, by gavage)], medium-dose Tianxiang pills (TXP-M, 5 g·kg-1, by gavage), and high-dose Tianxiang pills (TXP-H, 10 g·kg-1, by gavage). The fluorescent probe method was employed to measure the ROS level. Biochemical assay kits were employed to determine the Caspase-1 activity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and glutathione peroxidase (GSH-Px) activity. Myocardial infarct size was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Western blot analysis was performed to evaluate the expression levels of proteins in the ROS/Caspase-1/GSDMD pathway, including GSDMD, cleaved Caspase-1/Caspase-1 ratio, the N-terminal domain of GSDMD (GSDMD-N), and the p22-phox subunit of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Enzyme-linked immunosorbent assay (ELISA) was utilized to determine the concentration of interleukin-1β (IL-1β). Transmission electron microscopy (TEM) was employed to observe mitochondrial structure and to score the degree of mitochondrial swelling. ResultsCompared with the Sham group, the I/R group exhibited elevated the levels of ROS, Caspase-1 activity, GSDMD expression, IL-1β concentration, MDA content, infarct area, mitochondrial swelling score, cleaved Caspase-1/Caspase-1, GSDMD-N, and p22phox and decreased activities of SOD and GSH-Px (P<0.05). Compared with the I/R group, NAC and different doses of TXP significantly reduced the ROS level, Caspase-1 activity, GSDMD expression, IL-1β concentration, MDA content, infarct area, and mitochondrial swelling score. Moreover, they downregulated the expression of cleaved Caspase-1/Caspase-1, GSDMD-N, and p22phox and increased the activities of SOD and GSH-Px (P<0.05). Furthermore, TXP exerted effects on ROS, MDA, SOD, GSH-Px, Caspase-1 activity, GSDMD expression, IL-1β concentration, cleaved Caspase-1/Caspase-1, GSDMD-N, p22phox, infarct area, and mitochondrial swelling score in a dose-dependent manner (P<0.05). ConclusionTianxiang pills alleviates myocardial I/R injury by mitigating oxidative stress and cell pyroptosis through the inhibition of the ROS/Caspase-1/GSDMD signaling pathway.
4.Effects of miR-204-3p inhibitor on epithelial-mesenchymal transition and silicosis fibrosis in silicon dioxide-induced alveolar epithelial cells
Fang CHEN ; Jing YU ; Wenxuan HU ; Yangyang PI ; Xi ZHANG ; Luning WANG ; Ping ZHAO ; Faxuan WANG
Journal of Environmental and Occupational Medicine 2025;42(5):622-629
Background The pathogenesis of silicosis has not been fully elucidated, and microRNAs (miRNA) may be involved in the occurrence and development of silicosis. Objective To investigate the effect of miR-204-3p inhibitor on the epithelial-mesenchymal transition (EMT) process and silicosis fibrosis in silicon dioxide dust-induced alveolar epithelial cells. Methods A co-culture model of macrophages and epithelial cells was established using a Transwell chamber. NR8383 macrophages were seeded into the upper chamber of the Transwell, and RLE-6TN cells were seeded into the lower chamber. After 24 h of culture, the medium in the lower chamber was discarded, washed three times with phosphate-buffered saline (PBS), and replaced with serum-free medium. The cells were divided into four groups: control group, silicosis group, miRNA NC group, and miR-204-3p inhibitor group. The lower chamber was transfected with miRNA NC for the miRNA NC group or the miR-204-3p inhibitor for the miR-204-3p inhibitor group. The lower chambers of the remaining two groups were added by equal amounts of serum-free medium. After 24 h, except for the control group that received an equal volume of serum-free medium, the upper chambers of the remaining three groups were treated with 800 μg·mL−1 silicon dioxide dust. Morphological changes in each group were observed under a microscope. The mRNA and protein expression levels of EMT-related factors, including α-smooth muscle actin (α-SMA), Vimentin, N-Cadherin, and E-Cadherin, were detected by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot. The mRNA and protein expression levels of fibrosis-related factors, including Collagen I, Collagen III, and Fibronectin, were also assessed by RT-qPCR and Western blot. The fluorescence expression intensities of α-SMA, N-Cadherin, and E-Cadherin were evaluated by immunofluorescence. Results The morphological observation revealed that RLE-6TN cells in the control group exhibited a regular oval shape. After treatment with silicon dioxide, the cells predominantly displayed a long spindle shape. Following the intervention with the miR-204-3p inhibitor, the number of long spindle-shaped cells increased, and the intercellular gaps widened. The RT-qPCR results showed that, compared with the control group, the silicosis group exhibited significantly higher relative mRNA expression levels of EMT-related markers (α-SMA, Vimentin, and N-Cadherin) (P<0.05), while the relative mRNA expression level of E-Cadherin was significantly reduced (P<0.05); the relative mRNA expression levels of fibrosis-related markers (Collagen I, Collagen III, and Fibronectin) were also significantly elevated (P<0.05). Compared with the miRNA NC group, the miR-204-3p inhibitor group showed significantly increased relative mRNA expression levels of α-SMA, Vimentin, and N-Cadherin (P<0.05), decreased E-Cadherin mPNA expression (P<0.05), and elevated mPNA expression of Collagen I, Collagen III, and Fibronectin (P<0.05). The Western blot analysis indicated that, compared with the control group, the silicosis group had significantly higher protein expression levels of α-SMA, Vimentin, and N-Cadherin (P<0.05), lower E-Cadherin protein expression (P<0.05), and increased protein expression of Collagen I, Collagen III, and Fibronectin (P<0.05). Compared with the miRNA NC group, the miR-204-3p inhibitor group exhibited significantly elevated protein expression levels of α-SMA, Vimentin, and N-Cadherin (P<0.05), reduced E-Cadherin expression (P<0.05), and increased protein expression of Collagen I, Collagen III, and Fibronectin (P<0.05). The immunofluorescence analysis demonstrated that, compared with the control group, the silicosis group showed enhanced fluorescence intensities of α-SMA and N-Cadherin and reduced fluorescence intensity of E-Cadherin. Compared with the miRNA NC group, the miR-204-3p inhibitor group exhibited increased fluorescence intensities of α-SMA and N-Cadherin and decreased fluorescence intensity of E-Cadherin. Conclusion The miR-204-3p inhibitor may exacerbate the EMT process and silicosis fibrosis in silicon dioxide-induced RLE-6TN cells. miR-204-3p plays a negative regulatory role in silicosis fibrosis.
5.Construction of backpack-based field emergency medical rescue equipment system
Chen-xi LU ; Xin ZHAO ; Ming YU ; Shu-tian GAO ; Jing YUAN ; Yu-chen GUO ; Yun-dou WANG
Chinese Medical Equipment Journal 2025;46(10):17-22
Objective To establish a backpack-based field emergency medical rescue equipment system to enhance emergency rescue efficiency.Methods A backpack-based field emergency medical rescue equipment system was preliminarily constructed with the concept of medical treatment in echelons and prolonged field care(PFC)and the method of capability-based equipment need analysis;with the Delphi method 15 experts from relevant fields were invited to execute two rounds of questionnaire consultations,and the final equipment system was determined after the equipment varieties and quantities were revised based on the expert opinions.Results The response rate for the two rounds of expert questionnaire surveys was 100%.The experts'authority coefficients were 0.8734 and 0.87,respectively;Kendall coefficients were 0.232 and 0.345(both P<0.001),indicating statistically significant results.Ultimately,a backpack-based field emer-gency medical rescue equipment system comprising 15 backpacks and 158 individual pieces of equipment was established.Conclusion The established system demonstrates a certain degree of specificity and practicability,providing references for the equipment allocation and utilization of emergency medical rescue teams.[Chinese Medical Equipment Journal,2025,46(10):17-22]
6.Subchronic systemic toxicity of disposable plasma virus-inactivated blood transfusion sets
Qiu-jin QU ; Ling-xiao SUN ; Xiao-fei WANG ; Fu-yu ZHU ; Guo-xi CHE ; Jing XU ; Xiao-yan WANG ; Nai-shui HAN ; Xiao-xia SUN ; Chun-xia QIAO
Chinese Medical Equipment Journal 2025;46(10):29-35
Objective To evaluate the subchronic systemic toxicity of disposable plasma virus-inactivated blood transfusion sets using hydroxyethyl starch(HES)130/0.4 sodium chloride injection as an extraction medium.Methods Firstly,40 Sprague Dawley(SD)rats including 20 male and 20 female ones were seleted and randomly enrolled into a sample group and a control group by sex,with 20 ones in each group.Secondly,instead of plasma HES 130/0.4 sodium chloride injection was used to leach disposable plasma virus-inactivated blood transfusion sets to prepare the test solution by simulating clinical application such as lighting,adsorption and filtration and storage.Finally,the test solution and HES 130/0.4 sodium chloride injection were injected into the tail vein of the SD rats at a dose of 20 mL/kg for 28 d in the sample group and in the control group respectively,and the subchronic systemic toxicity of disposable plasma virus-inactivated blood transfusion sets and the feasibility of using HES 130/0.4 sodium chloride injection as the extraction medium to assess their subchronic systemic toxicity were evaluated with clinical observation,body mass monitoring,clinical pathology examination,gross necropsy and histopathology examination.Results The sample group and control group had no significant differences in mortality rates,clinical observation results,body mass,gross necropsy results,hematological and coagulation examination results and organ weight(all P>0.05);blood biochemical examinations showed the male rats in the sample group had the cholesterol(CHO)values higher while the creatinine(CR)values lower than those in the control group,with the differences being statistically significant(both P<0.05)and the two indexes within the range of the laboratory's historical reference data,and other blood biochemical indexes were not significantly different(all P>0.05);the sample group had the spleen weight-to-body mass ratios of the female rates lower significantly than those in the control group(P<0.05),and the ratios of other organ weight to body mass had significant differences(all P>0.05);histopathology examination showed slight pathological changes in liver,spleen and kidney of female rats and in spleen and kidney of male rats in the sample group,and the female and male rats in the control group had similar pathological changes found in the sample group,which might be caused by HES metabolites.Conclusion Disposable plasma virus-inactivated blood transfusion sets prove to have no significant subchronic systemic toxicity,and its feasible to use HES 130/0.4 sodium chloride injection as the extraction medium to evaluate the subchronic systemic toxicity of disposable plasma virus-inactivated blood transfusion sets.[Chinese Medical Equipment Journal,2025,46(10):29-35]
7.miR-204-3p affects silica dust-induced epithelial mesenchymal transition in a rat silicosis model
Jing YU ; Fang CHEN ; Wenxuan HU ; Yangyang PI ; Xi ZHANG ; Luning WANG ; Ping ZHAO ; Faxuan WANG
Chinese Journal of Comparative Medicine 2025;35(3):40-47
Objective To explore the role of miR-204-3p in silicosis and to elucidate the mechanism by which it affects silicosis fibers by regulating silica dust-induced alveolar epithelial-mesenchymal transition(EMT)in rats.Methods Forty SD rats were divided randomly into 4 groups:Control,Silicosis,AAV-Control,and AAV-miR-204-3p groups.The pathology of lung tissue damage was detected by hematoxylin and eosin(HE)and Masson staining.Relative expression levels of miR-204-3p and EMT marker genes in lung tissues from rats in each group were analyzed by real-time fluorescence reverse transcription quantitative PCR(RT-qPCR),and protein expression levels of EMT-related markers in lung tissues were detected by Western blot.Results The alveolar structure was damaged,the lung septa showed interstitial fibrosis,and expression levels of mesenchymal markers were elevated in the Silicosis group compared with the Control group(P<0.05,P<0.01,P<0.001).The alveolar structure was more complete,the EMT process was alleviated,fibrosis was improved,and mesenchymal marker expression was reduced in the AAV-miR-204-3p group compared with the AAV-Control group(P<0.05,P<0.01,P<0.001).Conclusions Free silica dust induces EMT in rat lung tissue.Overexpression of miR-204-3p can attenuate the EMT process induced by free silica dust in rats,and may thus affect silicosis fibrosis.
8.Radiation dose in interventional radiodiagnosis and radiotherapy and diagnostic reference level in Beijing
Jing JING ; Peng YU ; Xi WANG ; Dongkai SHAN ; Xinyan WU ; Yantao NIU
Chinese Journal of Radiological Medicine and Protection 2025;45(9):898-903
Objective:To investigate the relevant data on radiation dose in interventional radiodiagnosis and radiology of adults in Beijing and to provide a basis for establishing relevant diagnostic reference levels (DRLs) in this region.Methods:A total of 30 medical institutions in Beijing were surveyed, covering interventional radiodiagnosis and radiology surgeries for coronary artery, structural heart diseases, permanent cardiac pacemaker implantation, electrophysiological study and radiofrequency ablation, nervous systems, abdominal systems, and the blood vessels of the lower limbs. The primary parameters investigated included the air kerma area product ( PKA) and incident air kerma ( Ka, r). The 75 th percentiles of radiation dose were considered DRLs, which were analyzed at both the overall and individual medical institution levels. Results:A total of 3 331 cases of the abovementioned radiodiagnosis and radiology surgeries were collected. The DRLs (i.e., PKA and Ka, r) of various diagnostic examinations were 37.87 Gy·cm 2 and 509.00 mGy for coronary artery, 9.34 Gy·cm 2 and 48.00 mGy for electrophysiological study and radiofrequency ablation, 218.50 Gy·cm 2 and 901.70 mGy for nervous systems, 81.00 Gy·cm 2 and 302.20 mGy for the abdominal system, and 83.37 Gy·cm 2 and 214.69 mGy for the blood vessels of the lower limbs. In contrast, the DRLs (i.e., PKA and Ka, r) for interventional radiodiagnosis and radiology were determined at 135.00 Gy·cm 2 and 1 897.58 mGy for coronary artery, 26.91 Gy·cm 2 and 172.30 mGy for structural heart diseases, 27.77 Gy·cm 2 and 87.75 mGy for permanent cardiac pacemaker implantation, 34.46 Gy·cm 2 and 247.00 mGy for electrophysiological study and radiofrequency ablation, 214.36 Gy·cm 2 and 1 282.80 mGy for the nervous system, 196.64 Gy·cm 2 and 875.71 mGy for abdominal system, and 108.25 Gy·cm 2 and 523.25 mGy for the blood vessels of the lower limbs. Conclusions:The DRLs of radiation dose in interventional radiodiagnosis and radiology in Beijing were determined through a survey and statistic analysis. These findings suggest that for certain interventional procedures, the optimized radiation protection should be enhanced.
9.Construct a Prediction Model of Poor Prognosis of Anaphylactoid Purpura Children Based on Logistic Regression Analysis and Nomogram
Xi LIN ; Jing SUN ; Ze-yu YU ; Zhang-hua CHEN ; Wei YANG ; Xin-yu ZHANG
Progress in Modern Biomedicine 2025;25(12):1989-1995
Objective:The purpose of this study is to explore the influencing factors of poor prognosis in henoch-schonlein purpura(HSP)children,and to construct a nomogram model and verify its validity through the analysis results of Logistic regression model.Methods:Collected the clinical data of 170 HSP children who were treated in Fuzhou Luoyuan County Hospital from January 2015 to May 2023 were retrospectively analyzed.They were divided into good prognosis group and poor prognosis group according to the prognosis after treatment.The clinical data and related biochemical indexes of different prognostic groups were compared.The factors of poor prognosis in HSP children were analyzed by Logistic regression model.A predictive model(nomogram)for poor prognosis in HSP children were constructed and evaluated its predictive performance.Prediction accuracy were evaluateed by receiver operating characteristic(ROC)curve.Results:170 HSP children,69 cases(40.59%)had poor prognosis and 101 cases(59.41%)had good prognosis.C-reactive protein(CRP),kidney injury at initial onset,platelet count(PLT),respiratory infection,recurrent rash,and immunoglobulin A(IgA)levels in poor prognosis group were higher than those in good prognosis group(P<0.05).Multivariate logistic analysis showed that,recurrent rash,respiratory infection,elevated PLT,CRP and IgA levels were independent influencing factors of poor prognosis in HSP children(P<0.05).The consistency index(C-index)of the column chart model established based on the results of multiple factor analysis was 0.798.The internal verification was carried out by Bootstrap self-sampling method,and the average absolute error of calibration curve was 0.017.ROC curve was drawn according to independent influencing factors and nomogram prediction probability,the area under the curve was 0.674(recurrent rash),0.649(respiratory infection),0.777(PLT),0.733(CRP),0.749(IgA)and 0.910(nomogram prediction probability)respectively.Conclusion:Recurrent rash,respiratory infection,PLT,CRP and IgA are independent factors affecting the prognosis of HSP children.The column chart prediction model constructed based on the above factors has certain predictive value for the poor prognosis in HSP children.
10.Prevalence and molecular characterization of Shiga toxin-producing Esch-erichia coli in domestic goats in the Chengkou District of Chongqing
Jing-jing PENG ; Bin HU ; Xi YANG ; Yi LI ; Hai HUANG ; Wen-shuang LIU ; Yu MENG ; Li-jun WANG ; Yan-wen XIONG ; Yi YUAN ; Pei-bin HOU
Chinese Journal of Zoonoses 2025;41(5):529-536
This study investigated the infection status,drug resistance,and molecular characteristics of Shiga toxin-producing Escherichia coli(STEC)in domestic goats in Chengkou county,Chongqing.In August 2023,283 fecal samples were collected from households in Chengkou county.After enrichment with EC broth and inoculation onto selective media,samples that tested positive for stx1/stx2 were selected for further isolation.The positive strains were investigated with antimicrobial susceptibility testing and whole genome sequencing.According to the whole genomic sequences,the stx subtypes,serotypes,multi-locus sequence types,virulence genes,drug resistance genes,and phylogenetic relationships of the STEC strains were analyzed.Forty-six strains of STEC were isolated from 283 goat fecal samples,thus resulting in a detection rate of 16.25%.The 46 STEC strains were categorized into 12 O∶H serotypes,among which O76∶H19 and O8∶H7 predominated,each represented by 9 strains.Five STEC strains were identified as serotype O157∶H7.The 46 STEC strains were categorized into 11 sequence types(STs),among which ST675 and ST196 predominated,each represented by nine strains,accounting for a 19.57%proportion.The strains were categorized into 7 stx subtypes,among which stx1c(26/46,56.52%),followed by stx2k(9/46,19.57%)predominated.All nine Stx2k-STEC strains were identified as serotype O8∶H7 and sequence type ST196.In antimicrobial susceptibility testing,2 STEC strains were resistant to ampicillin,one strain was resistant to ampicillin/sulbactam,one strain was resistant to cefazolin,and one strain was resistant to cefoxitin.Nine Stx2k-STEC strains were found to carry the beta-lactam resistance gene blaEC-18.Antimicrobial sensitivity tests revealed that the nine Stx2k-STEC strains were sensitive to all 15 tested antibiotics.Moreover,phylogenetic analysis indicated that the 9 Stx2k-STEC strains were remarkably similar but showed high genetic diversity with respect to that of the Stx2k-STEC strains isolated from other regions in China.Goatsare an important animal reservoir for STEC in theChengkou district of Chongqing,and novel sequence type Stx2k-STEC strains distinct from those found in other regions of China were identified in this region.

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