Background Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants widely used in various products, leading to population exposure and long-term accumulation. At present, there is a lack of research on the relationships between pre-pregnancy PFAS and menstrual characteristics among women undergoing assisted reproductive technology (ART) in China. Objective To explore the relationships between pre-pregnancy PFAS exposure among women undergoing ART and menstrual characteristics prior to assisted reproductive treatment. Methods This study employed a cross-sectional research design, recruiting women undergoing ART treatment at the Reproductive Clinic of the International Peace Maternity & Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, from 2017 to 2020 as study participants. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to detect 42 types of PFAS in pre-pregnancy serum samples. Questionnaires were administered to collect information on demographic characteristics, lifestyle habits, and menstrual characteristics (average menstrual cycle length, average menstrual period length, menstrual irregularities, and menstrual bleeding volume) of women undergoing ART. Multiple linear regression, binary logistic regression, and multinomial logistic regression analyses were performed to investigate the relationships between individual PFAS exposure before pregnancy and menstrual characteristics among ART women. Additionally, weighted quantile sum (WQS) model was applied to analyze the association between PFAS mixtures and menstrual characteristics. Results In the pre-pregnancy serum samples of the study population, 15 PFAS were detected in more than 60% of the samples, including perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanesulfonic acid (PFHpS), perfluorooctanesulfonic acid (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), 8:2 chlorinated polyfluorinated ether sulfonate (8:2 Cl-PFESA), perfluoro-2-propoxypropanoic acid (HFPO-DA), perfluoro-2-methoxyacetic acid (PFMOAA), and perfluoro-(3,5,7,9,11-pentaoxadodecanoic) acid (PFO5DoDA). Among them, PFOA had the highest median concentration of 9.160 ng·mL⁻¹. The single PFAS exposure analysis revealed a positive correlation between PFAS and irregular menstrual cycles. Specifically, for every natural-log unit (e) increase in PFOA, PFBS, or PFHxS level, the incidence of irregular menstrual cycles increased by 57%, 42%, or 39%, respectively. Most PFAS were positively correlated with the average number of menstrual cycle days, such as PFHpA (b=1.08, 95%CI: 0.11, 2.05), PFOA (b=1.69, 95%CI: 0.39, 3.00), PFBS (b=1.23, 95%CI: 0.25, 2.22), PFHxS (b=1.47, 95%CI: 0.61, 2.32), PFHpS (b=1.48, 95%CI: 0.35, 2.61), and 6:2 Cl-PFESA (b=0.90, 95%CI: 0.08, 1.72). Furthermore, levels of PFHpA (OR=1.39, 95%CI: 1.06, 1.82), PFOA (OR=1.58, 95%CI: 1.09, 2.30), PFBS (OR=1.37, 95%CI: 1.04, 1.80), PFHxS (OR=1.34, 95%CI: 1.05, 1.71), PFHpS (OR=1.53, 95%CI: 1.10, 2.14), and 6:2 Cl-PFESA (OR=1.34, 95%CI: 1.06, 1.70) were positively correlated with low menstrual blood volume, while PFOA (OR=0.40, 95%CI: 0.23, 0.71), PFHpS (OR=0.45, 95%CI: 0.29, 0.71), and HFPO-DA (OR=0.68, 95%CI: 0.48, 0.97) were negatively correlated with high menstrual blood volume. The mixed exposure model showed that PFAS mixtures were positively correlated with the average number of menstrual cycle days (b=1.60, 95%CI: 0.49, 2.71), irregular menstrual cycles (OR=1.77, 95%CI: 1.19, 2.63), and low menstrual blood volume (OR=1.59, 95%CI: 1.08, 2.35), but negatively correlated with high menstrual blood volume (OR=0.40, 95%CI: 0.22, 0.73). Conclusion Women undergoing ART in Shanghai are widely exposed to PFAS prior to conception. Exposure to PFAS before pregnancy may be related to menstrual characteristics among women seeking ART before undergoing fertility treatments, but additional data from larger populations are required to validate the findings of this study.

ObjectiveTo establish a qualitative and quantitative analysis method for chemical constituents in Liu Junzitang（LJZT）， and to clarify its material basis. MethodThe chemical constituents in LJZT were analyzed by ultra performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS/MS）， and the resulting compounds were identified by using databases， such as MassBank， PubChem， ChemSpider， Traditional Chinese Medicine Systems Pharmacology Database and Analytical Platform（TCMSP）， and by combining with relevant literature. UPLC was used to establish a quantitative method for analysis of 9 compounds in LJZT， including liquiritin， hesperidin， lobetyolin， liquiritigenin， glycyrrhizic acid， nobiletin， tangeretin， atractylenolide Ⅱ and Ⅰ. ResultBy combining the relevant literature， database and MS information， a total of 79 compounds were identified from LJZT， including 31 flavonoids， 15 terpenoids， 14 nitrogen-containing compounds， 6 phenylpropanoids， 6 organic acids and 7 other compounds. The established quantitative analytical method for the nine representative components showed good linearity within their respective linear ranges， and the precision， stability， reproducibility and recovery were in accordance with the requirements. The quantitative results showed that the contents of liquiritin， hesperidin， lobetyolin， liquiritigenin， glycyrrhizic acid， nobiletin， tangeretin， atractylenolide Ⅱ and Ⅰ in LJZT were 0.376 5， 2.602 1， 0.082 6， 0.128 1， 1.778 6， 0.015 7， 0.006 7， 0.030 4， 0.003 2 mg·g^-1， respectively. ConclusionThe established method can quickly， sensitively and accurately analyze the chemical constituents in LJZT， clarify that the material basis of LJZT is mainly flavonoids， terpenoids and nitrogen-containing compounds， and simultaneously determine the contents of the 9 components， which can lay a foundation for the research on quality control， mechanism and clinical application of LJZT.

Objective To investigate the expression and clinical significance of SRY-box transcrip-tion factor 6(SOX6)and protein tyrosine phosphatase gene(PTEN)in patients with acute myo-cardial infarction(AMI).Methods A total of 100 AMI patients admitted to Zibo First Hospital and Zibo Central Hospital from January 2021 to March 2022 were enrolled as the study group,and according to the occurrence of major adverse cardiovascular events(MACE),they were grouped into MACE subgroup(52 cases)and non-MACE subgroup(48 cases).Another 110 volunteers who taking physical examination in above 2 hospitals during the same period were subjected as the control group.The levels of PTEN and SOX6 in the serum were detected,and Pearson correla-tion analysis was performed to investigate the correlation of serum PTEN and SOX6 levels with clinical indicators.ROC curve was drawn to assess the diagnostic value of PTEN and SOX6 levels for diagnosis and prognosis of AMI.Results The study group had significantly decreased serum mRNA level of SOX6(0.69±0.14 vs 1.03±0.16,P＜0.01)and increased serum mRNA level of PTEN(1.56±0.15 vs 1.05±0.08,P＜0.01)than the control group.Similar results were seen in the MACE subgroup than the non-MACE subgroup(SOX6:0.61±0.15 vs 0.78±0.13,P＜0.01;PTEN:1.74±0.18 vs 1.37±0.12,P＜0.01).Pearson correlation analysis showed that the serum level of PTEN was positively,and that of SOX6 was negatively correlated with cTnI,CK-MB and Gensini score(P＜0.01).ROC curve analysis indicated that the AUC value of combined serum SOX6 and PTEN levels for diagnosis of AMI was 0.932(95％CI:0.889-0.962),and that for pre-dicting MACE was 0.933(95％CI:0.866-0.974).Conclusion The serum level of SOX6 is down-regulated,and that of PTEN was up-regulated in AMI patients.Their combined detection is help-ful for diagnosis of AMI and prediction of MACE.

AIM To explore the effect of Heidihuang Pills on renal fibrosis in a rat model of chronic renal failure(CRF)and its mechanism.METHODS Wistar rats were randomly divided into the blank group for normal feeding and the model group for the establishment of CRF rat models by 5/6 nephrectomy.Subsequently,the successfully established rat models were randomly divided into the model group,the Heidihuang Pills group(10.43 g/kg),and the Heidihuang Pills+IGF-1R blocker(JB1)group for a regimen of 7-day subcutaneous injection of 18 μg/kg JB1 followed by gavage of 10.43 g/kg Heidihuang Pills.Eight weeks after the administration,the rats had their serum levels of Scr and BUN detected;their pathological changes of renal tissue observed by HE and Masson staining;their renal protein expressions of TGF-β,HIF-1α and α-SMA detected by immunohistochemistry;their renal protein expressions of IGF-1R and TGF-β detected by Western blot;and their renal mRNA expressions of IGF-1R and TGF-β detected by RT-qPCR.RESULTS Compared with the blank group,the model group displayed increased serum levels of Scr and BUN(P＜0.05);increased,degree of renal fibrosis,and renal fibrosis area(P＜0.05);increased renal expressions of TGF-β,HIF-1α,α-SMA proteins and TGF-β mRNA(P＜0.05);and decreased expressions of IGF-1R mRNA and protein(P＜0.05).Compared with the model group,the Heidihuang Pills group displayed decreased serum Scr and BUN levels(P＜0.05);decreased inflammatory cells in renal interstitium and the fibrosis degree(P＜0.05);decreased renal expressions of TGF-β,HIF-1α,α-SMA proteins and TGF-β mRNA(P＜0.05);and increased expressions of IGF-1R mRNA and protein(P＜0.05).However,the administration of JB1 could weaken the improvement effect of Heidihuang Pills on renal fibrosis in CRF rats(P＜0.05).CONCLUSION Heidihuang Pills can inhibit the renal fibrosis in CRF rats,and the inhibition process is related to up-regulated IGF-1 expression and promoted combination of IGF-1 and IGF-1R.

Objective:To analyze the genus, drug resistance/virulence and phylogenetic characteristics of Brucella strains isolated from brucellosis surveillance sentinels in Henan Province from 2013 to 2022, and provide baseline data for the surveillance, early warning and outbreak tracing of brucellosis. Methods:Blood samples were collected from patients with Brucella infection for strain isolation, culture and species identification, drug susceptibility test, whole genome sequencing, splicing and assembly, functional/virulence/resistance gene prediction analysis and phylogenetic tree drawing based on single nucleotide polymorphism (SNP). Results:In 36 brucellosis patients, the majority were men (86.11%, 31/36), young adults aged 18-50 (88.89%, 32/36) and farmers/herdsmen (72.22%, 26/36). A total of 36 strains of Brucella melitensis were isolated, and average 1 305 functional proteins of 21 categories were predicted by strain genome; all the strains carried four main virulence factors (pmm, VirB group, BtpA/BtpB, BvrS/BvrR). The drug sensitivity rate was 100.00% to six types of antibiotics including levofloxacin, rifampicin, doxycycline, streptomycin, tetracycline and gentamicin, they showed different resistances to three antibiotics including compound trimethoprim-sulfamethoxazole, ciprofloxacin and ampicillin. The strains carried four types of resistance genes and two clusters of resistance genes, with four combinations of genotypes, the resistance mechanisms included antibiotic degradation/modification enzymes, resistant nodular cell differentiation (RND) efflux pumps, 16S/23S ribosomal rRNA binding site mutations, etc. The number of SNP differed in the genomes of 36 Brucellamelitensis strains ranged from 0 to 454 and phylogenetic tree was divided into three major branches, with relative branch distances between 0.000 0 and 0.498 6 for each strain. Conclusions:Human Brucellamelitensis strains isolated from surveillance sentinels in Henan from 2013 to 2022 carried multiple virulence and antibiotic resistance genes and had different drug resistance phenotypes. Single nucleotide polymorphism analysis and phylogenetic tree analysis showed significant differences in phylogenetic relationships among different strains.

Objective:To discuss the improved methods for the isolation and culture of primary chondrocytes from the neonatal rats,and to establish an efficient and economical in vitro chondrocyte culture system.Methods:The primary chondrocytes were isolated from the joints of neonatal rats and divided into overnight digestion(OD)group and rapid digestion(RD)group for separation.The chondrocytes in OD group were digested overnight by type Ⅱ collagenase,while the chondrocytes in RD group were separated by the combination of pre-digestion with physical and chemical digestion methods.The chondrocytes were cultured in modified media containing 0％(blank group 1),1％,2％,4％,and 10％fetal bovine serum(FBS),0(blank group 2),0.1,0.2,0.4,0.8,1.0,and 2.0 g·L-1 vitamin C(VC),and 0(blank group 3),0.5,1.0,2.0,4.0,8.0,10.0 μg·L-1 poly(lactic-co-glycolic acid)(PLGA)nanoparticles.The media containing different concentrations of FBS,VC,and PLGA were mixed with Dulbecco's modified Eagle's medium/nutrient mixture F-12(DMEM/F12),and were divided into related groups based on the concentrations of ingredients.Cell counter was used to count the chondrocytes in various groups and the survival rates and diameters of the chondrocytes in various groups were detected;Toluidine blue staining was used to detect the morphology of the chondrocytes in various groups;CCK-8 method was used to detect the proliferative activities of the chondrocytes in various groups;cell adhesion assay was used to detect the adhesion rates of the chondrocytes in various groups;Hoechst/propidium iodide(PI)staining was used to detect the apoptosis of the chondrocytes in various groups;MTT assay was used to detect the proliferation activities of the chondrocytes in various groups after treated with modified media.The cells were divided into DMEM/F12+10％FBS group,DMEM/F12+1％FBS group,and DMEM/F12+1％FBS+0.4 g·L-1 VC+1 μg·L-1 PLGA group.Real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the expression levels of sex-determining region Y-box 9(SOX9),collagen type Ⅱ alpha 1 chain(Col2A1),collagen type X alpha 1 chain(Col10A1),and matrix metallopeptidase 13(MMP13)mRNAs in the chondrocytes in various groups after treated with modified media;immunofluorescence staining was used to detect the expressions of type Ⅱ collagen(COL Ⅱ)and SOX9 in the chondrocytes in various groups after treated with modified media.Results:The survival rate of primary chondrocytes in OD group was lower than that in RD group,and the average cell diameter was larger than that in RD group.The primary chondrocytes in OD group were larger and spindle-shaped,and most cells exhibited pseudopodia;in RD group,the primary chondrocytes were smaller,mostly rhomboid in shape,with only a portion of the cells showing pseudopodia.The Toluidine blue staining results showed significant coloration in both groups,but the digestion time of the chondrocytes in RD group was shorter,and compared with OD group,the actual culture time of the chondrocytes was reduced by 9-13 h,and more immature morphology of the primary chondrocytes were observed.The proliferation activity of the primary chondrocytes in OD group was slow at 24 h of culture but increased at 48 h of culture,and the proliferation activity of the primary chondrocytes was significantly higher at 48 h of culture compared with 12 h of culture(P＜0.01).Compared with 12 h of culture,the proliferation rates of the primary chondrocytes in RD group were increased at 24 and 48 h of culture(P＜0.01).At 24 and 48 h of culture,compared with OD group,the proliferation rates of the primary chondrocytes in RD group were increased(P＜0.05).The number of apoptotic chondrocytes in RD group was lower than that in OD group,and no necrotic chondrocytes were observed in either group.The proliferation activities of chondrocytes of the rats were increased with the rising of FBS concentration in the culture medium.Compared with blank group 1,the proliferation activities of chondrocytes of the rats after treated with culture mediums containing 1％,2％,4％,and 10％FBS were significantly increased(P＜0.05).Compared with blank group 2,the proliferative activities of chondrocytes of the rats after treated with culture mediums containing 0.2-1.0 g·L-1 VC were significantly increased(P＜0.05),and the highest proliferation activity was found when the concentration of VC was 0.4 g·L-1(P＜0.01).Compared with blank group 3,the proliferation activities of chondrocytes of the rats after treated with culture mediums containing 1-4 μg·L-1 PLGA were significantly increased(P＜0.05),and the highest proliferation activity was found after treated with culture medium containing 1 μg·L-1 PLGA(P＜0.05).Compared with DMEM/F12+10％FBS group,the expression levels of SOX9 mRNA and Col2A1 mRNA in the chondrocytes in DMEM/F12+1％FBS group were significantly increased(P＜0.05 or P＜0.01).Compared with DMEM/F12+10％FBS group,the expression levels of SOX9 mRNA and Col2A1 mRNA in the chondrocytes in DMEM/F12+1％FBS+0.4 g·L-1 VC+1 μg·L-1 PLGA group were significantly increased(P＜0.01).The immunofluorescence staining results showed that the green fluorescence signal of COL Ⅱ and the red fluorescence signal of SOX9 were observed in some chondrocytes in DMEM/F12+10％FBS group under fluorescence microscope,and the fluorescence intensity was weak.In DMEM/F12+1％FBS group,most chondrocytes exhibited COL Ⅱ green fluorescence signal and SOX9 red fluorescence signal,and the fluorescence intensity was significantly stronger than that in DMEM/F12+10％FBS group.In DMEM/F12+1％FBS+0.4 g·L-1 VC+1 μg·L-1 PLGA group,the COLⅡ green fluorescence signal and SOX9 red fluorescence signal were found in all the chondrocytes,and the fluorescence intensity was significantly higher than those in DMEM/F12+10％FBS and DMEM/F12+1％FBS groups.The expression levels of COLⅡ and SOX9 proteins in the chondrocytes in DMEM/F12+1％FBS group were significantly higher than those in DMEM/F12+10％FBS group,and the expression levels of COL Ⅱ and SOX9 proteins in the chondrocytes in DMEM/F12+1％FBS+0.4 g·L-1 VC+1 μg·L-1 PLGA group were significantly higher than those in DMEM/F12+10％FBS group.Conclusion:The improved methods for the isolation and culture of primary chondrocytes of the rats can overcome the shortcomings of traditional methods,shorten the isolation time of primary chondrocytes,and improve the quality of in vitro culture of primary chondrocytes.

Objective To study the distribution of intestinal flora in osteoporosis patients with spleen deficiency syndrome.Methods According to the diagnostic criteria of osteoporosis of the World Health Organization(WHO)and the syndrome differentiation criteria of spleen deficiency syndrome in traditional Chinese medicine(TCM),26 healthy attenders with normal bone mass while without spleen deficiency were selected from the population visited Shunde Hospital of Guangzhou University of Chinese Medicine from January 2022 to September 2023 as the normal bone mass group,23 patients with bone mass reduction and spleen deficiency syndrome served as decreased bone mass with spleen deficiency group(shorten as DBM-SD group),and 69 patients with osteoporosis and spleen deficiency syndrome diagnosis were osteoporosis with spleen deficiency group(shorten as OS-SD group).A total of 118 attenders were enrolled in the analysis.The gender,age,body height,body weight,and body mass index(BMI)of the subjects were collected.The bone mineral density(BMD)and serum levels of calcium and alkaline phosphatase(ALP)of the subjects were measured.Stools were collected for the detection of the sequence of the 16SrRNA V3-V4 region,and the sequencing results were given species annotation,and then the correlation of community difference between groups and BMD with the intestinal flora was explored.Results(1)There were significant differences in the relative abundance of intestinal flora between the normal bone mass group and the OS-SD group:differences were shown in Firmicutes(t=2.490,P=0.016),Verrucomicrobia(t=2.180,P=0.003)and Fusobacteria(t=2.270,P=0.026),in Acidobacteria(t=3.003,P=0.003),Lactobacillus(t=3.150,P=0.002)and Bifidobacterium(t=7.248,P=0.001),and in Fecalibacterium(t=2.810,P=0.006)and Rothia(t=2.810,P=0.006).(2)There were significant differences in the relative abundance of intestinal flora between the normal bone mass group and the DBM-SD group:differences were shown in Lactobacillus(t=3.841,P=0.001)and Bifidobacterium(t=2.712,P=0.01),and in Faecalibacterium(t=2.466,P=0.017).(3)There were significant differences in the relative abundance of intestinal flora between the OS-SD group and DBM-SD group:differences were shown in Firmicutes(t=2.321,P=0.025),Bacteroidetes(t=0.393,P=0.020)and Verrucomicrobia(t=3.109,P=0.031).(4)The results of logistic regression analysis showed that in the OS-SD group,lumbar BMD was negatively correlated with Lactobacillus(R=0.355,P=0.003)and Bifidobacterium(R=0.366,P=0.002),positively correlated with Bacteroides(R=0.245,P=0.042),and was negatively correlated Rothia(R=0.330,P=0.006).Conclusion Some bacteria in the intestinal flora are related to the BMD of osteoporosis patients with spleen deficiency syndrome,and significant difference exists in the distribution of intestinal flora between the normal bone mass group and the OS-SD group.The results will provide a theoretical basis for the prevention and treatment of osteoporosis patients with spleen deficiency syndrome from the perspective of the changes of intestinal flora.

Objective Objective To investigate the clinical characteristics of a hereditary protein S deficiency family with acute cerebral infarction and to analyze the mutational characteristics of the PROS1 gene.Methods Clinical data of the proband and their immediate family members were collected,blood samples were obtained,protein S activity levels were analyzed,and PROS1 genes were sequenced.Results The family consisted of three generations and eight direct relatives.Among them,three individuals were diagnosed with hereditary protein S deficiency.The proband and his brother suffered from acute cerebral infarction,while the other family members had not yet experienced thrombotic events.The protein S activity levels of the proband,his brother and their mother were 16.8%,38.0%and 31.8%,respectively,while the father's levels were normal.Gene test found that the proband,his brother and their mother possessed a heterozygous variant c.1323G>A in exon 11 in PROS1,while his father exhibited the wild-type.Conclusions The study reports the identification of a familial protein S deficiency,which is attributed to a novel synonymous mutation(c.1323G>A)in the PROS1 gene.This genetic alteration may lead to ischemic stroke in youth.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.