ObjectiveTo investigate somatization symptoms in adolescents during frequent earthquakes in Hefei， and to explore their correlation with earthquake experiences. MethodsA cross-sectional survey was used to select 324 adolescents in Hefei as the survey objects. The self-rating scale of somatization symptoms （SSS） and the fatigue intensity scale （FIS） were used to evaluate the somatization symptoms and fatigue degree of middle school students， and multivariate Logistic regression analysis was used to explore the related factors of somatization symptoms and fatigue among middle school students. ResultsA total of 324 adolescents were included， and the overall detection rate of somatization symptoms was 6.5%， and the detection rate of moderate or above fatigue was 20.1%. The results of regression analysis showed that adolescents who were concerned about the earthquake for a longer time （≥1 h） had a higher risk of somatization symptoms （OR=5.430， 95%CI： 1.547-19.058）， and adolescents who received pre-earthquake training had a lower degree of fatigue （OR=0.535， 95%CI： 0.292-0.981） （P<0.05）. ConclusionDuring the frequent earthquakes， adolescents have more somatization symptoms and fatigue. Therefore， it is crucial to enhance health education， reduce the emphasis on event-related reports， and implement earthquake prevention and disaster reduction training to improve the physical and mental health of adolescents.

Dry eye （DE） is a prevalent multifactorial disease of the ocular surface， clinically characterized by tear film homeostasis imbalance accompanied by related ocular surface symptoms. Specifically， the tear film is a thin liquid layer of tears covering the cornea and conjunctiva through blinking， while tear film homeostasis serves as the foundation for maintaining normal ocular surface structure and function. Insufficient tear secretion and excessive tear film evaporation lead to tear hyperosmolarity and the production of inflammatory mediators， disrupting tear film homeostasis and subsequently forming DE. Additionally， cascade reactions are triggered， resulting in a "vicious cycle of DE" that exacerbates the disease severity and prolongs its duration. Therefore， for DE treatment， it is crucial to restore tear film homeostasis and terminate this vicious cycle. Traditional Chinese medicine （TCM）， which differentiates and treats DE based on systemic conditions， often achieves favorable therapeutic outcomes， offering additional treatment options for DE. Studies have demonstrated that TCM can alleviate DE by regulating tear film homeostasis and terminating the vicious cycle. This review systematically summarizes recent basic experimental research in China and abroad on TCM in alleviating DE by regulating tear film homeostasis， aiming to provide a theoretical basis for clinical treatment and an insight for research design.

ObjectiveTo establish a model of dry eye with lung Yin deficiency syndrome in mice. MethodsA total of 40 SPF C57BL/6J mice were assigned via the random number table method into 5 groups （n=8）： Normal control， model control， and high-， medium-， and low-dose （11.7， 5.85， and 2.925 g·kg^-1， respectively） Yangyin Qingfeitang. Mice in the normal control group were fed normally without any intervention. Mice in Yangyin Qingfeitang group and model control group were treated with 0.2% benzalkonium chloride eye drops （5 μL） twice a day and fed in a controlled drying system in a dry environment for 28 days. At the same time， the mice were administrated with thyroxine tablet solution by gavage and placed in a glass fumigation tank （SO₂ concentration： 0.5 g·m^-3） for 14 days. After 4 weeks， mice in Yangyin Qingfeitang groups were treated with Yangyin Qingfeitang by gavage and those in the normal control group and model control group were administrated with deionized water at 0.01 mL·g^-1. The body mass， anal temperature， four examination information （claw and nail appearance）， basic tear secretion test， tear film rupture time， corneal fluorescein staining， and lacrimal gland HE staining were compared among groups. Compound Yangyin Qingfeitang granules were used to measure the syndrome to verify the success of modeling. ResultsAfter 28 days of continuous modeling， compared with the normal control group， the model group exhibited listless and emaciated status， coughing， drowsiness， dry and dull hair， dry and hard stool， reduced food intake and water intake， red lip circumference， red tongue with reduced fluid， dry nose and teeth， red claws and nails， body mass gain， decreased anal mild tear secretion （P<0.05）， and shortened tear film rupture time （P<0.05）. After 28 days of modeling， the mice showed large corneal fluorescein staining range， severe corneal injury， and increased content of interleukin （IL）-18， IL-β， and tumor necrosis factor （TNF）-α in lacrimal gland， compared with those in the normal control group （P<0.05）. After the treatment with Yangyin Qingfeitang， the mice had good drinking and eating conditions， with lighter redness of the tongue， moist nose， moist and shiny teeth， and the claw and nail color close to that in the normal group. Compared with the model control group， Yangyin Qingfeitang groups showed increases in body mass and anal temperature （P<0.05）， tear secretion （P<0.05）， and tear film rupture time （P<0.05）， narrowed range of corneal fluorescein staining， and declined levels of IL-18， IL-β， and TNF-α in lacrimal glands （P<0.01）. The high-dose group had the best effect， with the indicators close to the levels in the normal control group. ConclusionThe animal model of dry eye with lung Yin deficiency syndrome can be established by culture in a controlled drying system， treatment with benzalkonium chloride eye drops for 28 days， and administration of thyroxine tablet solution combined with SO₂ fumigation for 14 days.

ObjectiveTo investigate the mechanisms of Runmu Dihuang decoction （RMDHD） in treating perimenopausal dry eye with liver-kidney Yin deficiency syndrome based on the silent information regulator 3 （SIRT3）/hypoxia-inducible factor-1α （HIF-1α）/nuclear factor-κB （NF-κB） signaling pathway. MethodsSixty female Sprague-Dawley rats were randomly divided into six groups （n=10 per group）： Sham operation group， model group， sodium hyaluronate eye drop group， and low-， medium-， and high-dose RMDHD groups （5.625， 11.25， 22.50 g·kg^-1）. Except for the sham operation group， all rats underwent bilateral ovariectomy and were administered 0.1% benzalkonium chloride eye drops combined with long-term chronic irritation to establish a perimenopausal dry eye model with liver-kidney Yin deficiency syndrome. Drug administration began in the 11th week after modeling and continued for 21 days. General conditions， screen-grip test scores， tear secretion volume， tear film breakup time （TFBUT）， and corneal fluorescein staining were recorded. Serum levels of reactive oxygen species （ROS）， follicle-stimulating hormone （FSH）， estradiol （E₂）， and progesterone （PROG） were measured by enzyme-linked immunosorbent assay （ELISA）. Pathological changes in the lacrimal glands， corneas， and uteri were observed using hematoxylin-eosin （HE） staining. Protein expression levels of SIRT3， HIF-1α， phosphorylated NF-κB p65 （p-NF-κB p65）， and total NF-κB p65 in the lacrimal glands were detected by Western blot. The expression of inflammatory cytokines interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） in the lacrimal glands was assessed by immunohistochemistry （IHC）. ResultsAfter model establishment， no significant differences were observed among the groups except the sham operation group. Compared with the sham operation group， the other groups exhibited slowed movement， dull responses， increased irritability， reduced body weight， elevated rectal temperature， decreased screen-grip test scores， reduced tear secretion， and significantly shortened TFBUT （P<0.05）. After treatment， compared with the model group， the sodium hyaluronate eye drop group and all RMDHD groups showed improved general conditions， significantly increased tear secretion （P<0.05）， prolonged TFBUT （P<0.05）， and elevated screen-grip test scores （P<0.05）. Serum ROS and FSH levels were significantly decreased， while E₂ and PROG levels were significantly increased （P<0.05）. Pathological damage to the cornea， lacrimal glands， and uterus was ameliorated. In addition， protein expression levels of SIRT3 and HIF-1α in the lacrimal glands were significantly upregulated （P<0.05）， whereas the expression of p-NF-κB p65， IL-1β， and TNF-α was significantly downregulated （P<0.05）. ConclusionRMDHD increases tear secretion and TFBUT， improves lacrimal gland and corneal injury， and alleviates dry eye symptoms in a perimenopausal dry eye rat model with liver-kidney Yin deficiency syndrome. The underlying mechanism may be related to regulation of the SIRT3/HIF-1α/NF-κB signaling pathway， inhibition of oxidative stress and inflammatory responses， and reduction of ocular surface tissue damage.

ObjectiveThis paper aims to investigate the effects and mechanism of Mimenghua prescription in modulating the mitogen-activated protein kinase kinase （MEK）/rat sarcoma viral oncogene homolog （Ras）/rapidly accelerated fibrosarcoma kinase （Raf）/extracellular signal-regulated kinase （ERK） signaling pathway to inhibit inflammatory responses in a dry eye animal model. MethodsA total of 60 C57BL/6J mice （eight weeks old， half male and half female） were used in the experiment. Ten mice were randomly selected as the blank control group， while the remaining 50 were exposed to a controlled dry system and received instillation of 0.2% benzalkonium chloride （BAC） into the eyes for four weeks to establish a dry eye mouse model. After successful modeling， the mice were randomly divided into five groups： Model group， sodium hyaluronate group， and Mimenghua prescription groups with low dose （4.83 g·kg^-1）， medium dose （9.67 g·kg^-1）， and high dose （19.34 g·kg^-1）. The mice in the model group received an equal volume of normal saline via gavage for four weeks. The mice in the sodium hyaluronate group received instillation of sodium hyaluronate eye drops twice daily for 14 consecutive days. The tear secretion volume， tear film break-up time （TBUT）， and corneal fluorescein staining were evaluated once every two weeks. After four weeks of administration， mice were euthanized， and their lacrimal gland tissues and corneas were harvested. Hematoxylin-eosin （HE） staining was used to assess histopathological morphology. Western blot was performed to detect the protein expression levels of MEK， Ras， Raf， and ERK. Enzyme-linked immunosorbent assay （ELISA） was used to measure the contents and expressions of MEK， Ras， Raf， ERK， and interleukin （IL）-1β in lacrimal gland and corneal tissues of the mice in each group. Quantitative real-time polymerase chain reaction （Real-time PCR） was employed to determine mRNA expression levels of MEK， Ras， Raf， and ERK. ResultsThe Mimenghua prescription groups and the sodium hyaluronate group exhibited significantly increased tear secretion volume （P<0.05） and prolonged TBUT （P<0.05） after treatment. Ocular surface damage of mice was visibly recovered. Western blot results indicated that protein expression levels of MEK， Ras， Raf， and ERK in the lacrimal gland and corneal tissues were significantly downregulated in the sodium hyaluronate group and Mimenghua prescription group with high dose （P<0.05）. ELISA results showed that IL-1β levels were highest in the model group but significantly reduced in the sodium hyaluronate group and Mimenghua prescription groups （P<0.05）. Both ELISA and Real-time PCR results demonstrated that the expression levels of MEK， Ras， Raf， and ERK in the lacrimal glands and corneal tissues were significantly elevated in the model group （P<0.05）， but markedly downregulated in the sodium hyaluronate group and Mimenghua prescription groups （P<0.05）， suggesting that Mimenghua prescription can decrease the expressions of MEK， Ras， Raf， and ERK in the lacrimal glands and corneal tissues. ConclusionMimenghua prescription can reduce inflammatory responses， increase tear secretion， prolong TBUT， and promote corneal recovery by inhibiting the MEK， Ras， Raf， and ERK signaling pathways in lacrimal gland and corneal tissues.

ObjectiveTo explore the effect of gypenosides （GPs） on liver lipid deposition in metabolism-associated fatty liver disease （MAFLD） mice and its mechanism based on classical/non-classical ferroptosis. MethodsEight male C57BL/6 mice in a blank group and 32 male apolipoprotein E gene knockout （ApoE^-/-） mice were randomly divided into a model group， a low-dose GPs （GPs-L） group， a high-dose GPs （GPs-H） group， and a simvastatin （SV） group. Starting from the second week， mice in the blank group were given a maintenance diet， and the other four groups were fed a high-fat diet daily. After eight weeks of feeding， mice in the GPs-L and GPs-H groups were given GPs of 1.487 mg·kg^-1·d^-1 and 2.973 mg·kg^-1·d^-1， respectively， and mice in the SV group were given simvastatin of 2.275 mg·kg^-1·d^-1. Mice in the blank group and the model group were given saline of equal volume by gavage for four weeks. The content of total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， high-density lipoprotein cholesterol （HDL-C）， alanine aminotransferase （ALT）， and aspartate aminotransferase （AST） in the serum of mice in each group was detected by an automatic biochemical analyzer. The level of non-esterified fatty acid （NEFA） and TG in the mouse liver was measured by the kit. The change in liver tissue structure and lipid deposition was observed by hematoxylin-eosin （HE） and oil red O staining. The levels of coenzyme Q₁₀ （CoQ₁₀）， glutathione （GSH）， malondialdehyde （MDA）， and Fe²⁺ in serum， as well as nicotinamide adenine dinucleotide phosphate ［NAD（P）H］ in the liver were detected by enzyme-linked immunosorbent assay （ELISA）. The expression of ferroptosis suppressor protein 1 （FSP1） in the liver of mice was observed by the immunohistochemical （IHC） method， and the expression of genes and proteins related to classical and non-classical ferroptosis pathways was analyzed by real-time polymerase chain reaction （Real-time PCR） and Wes automated protein expression analysis system. ResultsCompared with those in the blank group， the levels of TC， TG， LDL-C， ALT， and AST in serum and TG and NEFA in the liver in the model group were significantly increased， and the level of HDL-C in serum was significantly decreased （P<0.01）. The liver tissue structure changed， and there were fat vacuoles of different sizes and a large number of red lipid droplets， with obvious lipid deposition. The level of CoQ10 and GSH in serum and NADH in the liver were significantly decreased， while the level of MDA and Fe²⁺ in serum was significantly increased （P<0.01）. The mRNA and protein expressions of cystine/glutamate transporter （xCT/SLC7A11）， glutathione peroxidase （GPX4）， p62， nuclear factor E₂-related factor 2 （Nrf2）， and FSP1 were significantly decreased， and the mRNA and protein expressions of tumor antigen （p53）， spermidine/spermine N1-acetyltransferase 1 （SAT1）， arachidonate 15-lipoxygenase （ALOX15）， and Kelch-like epichlorohydrin-associated protein-1 （Keap1） were significantly increased （P<0.01）. Compared with those in the model group， the level of TC， TG， LDL-C， ALT， and AST in serum and TG and NEFA in the liver of mice in the GPs-L， GPs-H， and SV groups were decreased， while the level of HDL-C in serum was significantly increased （P<0.05， P<0.01）. The liver tissue structure and lipid deposition were improved. The levels of CoQ10 and GSH in serum and NADH in the liver were significantly increased， while the levels of MDA and Fe²⁺ in serum were significantly decreased （P<0.05， P<0.01）. The mRNA and protein expressions of xCT， GPX4， p62， Nrf2， and FSP1 were significantly increased， while the mRNA and protein expressions of p53， SAT1， ALOX15， and Keap1 were significantly decreased （P<0.05， P<0.01）. ConclusionGPs can interfere with liver lipid deposition in MAFLD mice through classical/non-classical ferroptosis pathways.

ObjectiveTo explore the effect of gypenosides （GPs） on liver lipid deposition in metabolism-associated fatty liver disease （MAFLD） mice and its mechanism based on classical/non-classical ferroptosis. MethodsEight male C57BL/6 mice in a blank group and 32 male apolipoprotein E gene knockout （ApoE^-/-） mice were randomly divided into a model group， a low-dose GPs （GPs-L） group， a high-dose GPs （GPs-H） group， and a simvastatin （SV） group. Starting from the second week， mice in the blank group were given a maintenance diet， and the other four groups were fed a high-fat diet daily. After eight weeks of feeding， mice in the GPs-L and GPs-H groups were given GPs of 1.487 mg·kg^-1·d^-1 and 2.973 mg·kg^-1·d^-1， respectively， and mice in the SV group were given simvastatin of 2.275 mg·kg^-1·d^-1. Mice in the blank group and the model group were given saline of equal volume by gavage for four weeks. The content of total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， high-density lipoprotein cholesterol （HDL-C）， alanine aminotransferase （ALT）， and aspartate aminotransferase （AST） in the serum of mice in each group was detected by an automatic biochemical analyzer. The level of non-esterified fatty acid （NEFA） and TG in the mouse liver was measured by the kit. The change in liver tissue structure and lipid deposition was observed by hematoxylin-eosin （HE） and oil red O staining. The levels of coenzyme Q₁₀ （CoQ₁₀）， glutathione （GSH）， malondialdehyde （MDA）， and Fe²⁺ in serum， as well as nicotinamide adenine dinucleotide phosphate ［NAD（P）H］ in the liver were detected by enzyme-linked immunosorbent assay （ELISA）. The expression of ferroptosis suppressor protein 1 （FSP1） in the liver of mice was observed by the immunohistochemical （IHC） method， and the expression of genes and proteins related to classical and non-classical ferroptosis pathways was analyzed by real-time polymerase chain reaction （Real-time PCR） and Wes automated protein expression analysis system. ResultsCompared with those in the blank group， the levels of TC， TG， LDL-C， ALT， and AST in serum and TG and NEFA in the liver in the model group were significantly increased， and the level of HDL-C in serum was significantly decreased （P<0.01）. The liver tissue structure changed， and there were fat vacuoles of different sizes and a large number of red lipid droplets， with obvious lipid deposition. The level of CoQ10 and GSH in serum and NADH in the liver were significantly decreased， while the level of MDA and Fe²⁺ in serum was significantly increased （P<0.01）. The mRNA and protein expressions of cystine/glutamate transporter （xCT/SLC7A11）， glutathione peroxidase （GPX4）， p62， nuclear factor E₂-related factor 2 （Nrf2）， and FSP1 were significantly decreased， and the mRNA and protein expressions of tumor antigen （p53）， spermidine/spermine N1-acetyltransferase 1 （SAT1）， arachidonate 15-lipoxygenase （ALOX15）， and Kelch-like epichlorohydrin-associated protein-1 （Keap1） were significantly increased （P<0.01）. Compared with those in the model group， the level of TC， TG， LDL-C， ALT， and AST in serum and TG and NEFA in the liver of mice in the GPs-L， GPs-H， and SV groups were decreased， while the level of HDL-C in serum was significantly increased （P<0.05， P<0.01）. The liver tissue structure and lipid deposition were improved. The levels of CoQ10 and GSH in serum and NADH in the liver were significantly increased， while the levels of MDA and Fe²⁺ in serum were significantly decreased （P<0.05， P<0.01）. The mRNA and protein expressions of xCT， GPX4， p62， Nrf2， and FSP1 were significantly increased， while the mRNA and protein expressions of p53， SAT1， ALOX15， and Keap1 were significantly decreased （P<0.05， P<0.01）. ConclusionGPs can interfere with liver lipid deposition in MAFLD mice through classical/non-classical ferroptosis pathways.

Lung cancer is the most common malignant tumor worldwide, ranking first in both incidence and mortality rates. According to the latest statistics from the International Agency for Research on Cancer (IARC), approximately 2.5 million new cases and around 1.8 million deaths from lung cancer occurred in 2022, placing a tremendous burden on global healthcare systems. The high mortality rate of lung cancer is closely linked to its subtle early symptoms, which often lead to diagnosis at advanced stages. This not only complicates treatment but also results in substantial economic losses. Current treatment options for lung cancer include surgery, radiotherapy, chemotherapy, targeted drug therapy, and immunotherapy. Among these, immunotherapy has emerged as the most groundbreaking advancement in recent years, owing to its unique antitumor mechanisms and impressive clinical benefits. Unlike traditional therapies such as radiotherapy and chemotherapy, immunotherapy activates or enhances the patient’s immune system to recognize and eliminate tumor cells. It offers advantages such as more durable therapeutic effects and relatively fewer toxic side effects. The main approaches to lung cancer immunotherapy include immune checkpoint inhibitors, tumor-specific antigen-targeted therapies, adoptive cell therapies, cancer vaccines, and oncolytic virus therapies. Among these, immune checkpoint inhibitors and tumor-specific antigen-targeted therapies have received approval from the U.S. Food and Drug Administration (FDA) for clinical use in lung cancer, significantly improving outcomes for patients with advanced non-small cell lung cancer. Although other immunotherapy strategies are still in clinical trials, they show great potential in improving treatment precision and efficacy. This article systematically reviews the latest research progress in lung cancer immunotherapy, including the development of novel immune checkpoint molecules, optimization of treatment strategies, identification of predictive biomarkers, and findings from recent clinical trials. It also discusses the current challenges in the field and outlines future directions, such as the development of next-generation immunotherapeutic agents, exploration of more effective combination regimens, and the establishment of precise efficacy prediction systems. The aim is to provide a valuable reference for the continued advancement of lung cancer immunotherapy.

Objective:To investigate the association between the triglyceride-glucose(TyG)index and the incidence and mortality of cardiovascular disease(CVD)in a large population-based cohort.Methods:Participants aged 40-79 years without a history of CVD at baseline were drawn from the CHi-nese Electronic health Records Research in Yinzhou(CHERRY)study between January 1,2010,and May 31,2020.The TyG index was calculated using baseline triglyceride and fasting blood glucose.Cox proportional hazards models were used to assess the association between the TyG index and the composite outcome of CVD(incidence and mortality),adjusting for age,gender,education,region,smoking sta-tus,body mass index,systolic blood pressure,and total cholesterol.Hazard ratios(HR)and 95％confi-dence intervals(CI)were calculated.Nonlinear associations between the TyG index and CVD were fur-ther evaluated using restricted cubic splines,and subgroup analyses by gender and age were conducted to explore potential differences.Results:A total of 226 406 individuals were included,with a mean age of(55.0±9.7)years at baseline,46.8％of whom were men,and a median TyG index of 8.68.Over a median follow-up of 7.99 years,9 815(4.34％)participants experienced CVD incidence or mortality.After adjusting for age,gender,education,region,smoking status,body mass index,systolic blood pressure and total cholesterol,the risk of CVD increased with higher TyG index levels(P＜0.001).The risk in the highest TyG quartile(TyG＞9.10)was 42％higher than in the lowest quartile(TyG ≤8.32)(HR=1.42,95％CI:1.34-1.51).Individuals under 60 years had a higher HR for CVD compared with those aged 60 years and above(HR:1.71 vs.1.27,P＜0.05).Restricted cubic spline analysis revealed a reverse L-shaped association between the TyG index and CVD risk in the overall population(P＜0.001 for nonlinear trend),with risk increasing after the TyG index exceeded 8.67.However,the threshold varied by gender,with a lower threshold in women(8.51)than in men(8.67).Conclusion:A significant nonlinear relationship was revealed between the TyG index and CVD risk,with a threshold effect.The risk of CVD increased once the TyG index surpassed a certain threshold,with a lower threshold in women than in men.These findings suggest that cardiovascular risk prediction and interven-tions based on the TyG index should be gender-stratified,and early intervention for individuals under 60 years old might have important public health implications.

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.