Background Toluene and chlorobenzene have been designated as surrogate contaminants in the challenge test for evaluating the safety of recycling processes for food-contact recycled polyethylene terephthalate (rPET). Establishing a reliable analytical method is essential for ensuring the compliant use of rPET and safeguarding food safety. Objective To develop a rapid quantitative method for determining toluene and chlorobenzene in rPET using headspace gas chromatography-mass spectrometry (HS-GC-MS), as part of the challenge test for process safety evaluation. Methods The effects of different chromatographic columns and headspace conditions on detection of target analytes were investigated. Three columns HP-5 ms UI (30 m×0.25 mm×0.25 μm), DB-624 (30 m×0.32 mm×1.8 μm), and VF-WAXms (30 m×0.25 mm×0.25 μm) were compared for separation efficiency and peak shape. Headspace equilibration temperatures (50-100 ℃) and equilibration times (10-30 min) were evaluated to determine the optimal instrumental parameters. The effect of sample grinding on recovery was assessed to select the best pretreatment conditions. The established method was validated for selectivity, linearity, sensitivity, accuracy, and precision, and was subsequently applied to the analysis of 12 rPET samples. Results The target analytes achieved good separation and response within 15 min, under the optimized conditions using an HP-5 ms UI column, a headspace equilibration temperature of 60 ℃ and a 10 min equilibration time. Direct analysis without grinding yielded satisfactory recovery rates. Toluene and chlorobenzene showed excellent linearity (0.0030-5.0 mg·kg⁻¹, R²≥0.999). The limits of detection (LOD) and quantification (LOQ) were 0.00003 mg·kg⁻¹ and 0.00011 mg·kg⁻¹ for toluene respectively, and 0.00011 mg·kg⁻¹ and 0.00037 mg·kg⁻¹ for chlorobenzene respectively. The recoveries of the matrix spike at low and high spiking levels ranged from 88.6% to 110%, with relative standard deviations of 0.52%-4.9% (n=6). Among the 12 rPET samples from different recycling stages, three samples contained detectable levels of toluene (0.196-0.250 mg·kg⁻¹) and chlorobenzene (0.704-0.867 mg·kg⁻¹). Conclusion The proposed method is simple, rapid, highly sensitive, and accurate, making it suitable for determining toluene and chlorobenzene in food-contact rPET. It provides a robust technical approach for the safety evaluation of rPET recycling processes.

ObjectiveTranscranial magneto-acoustic stimulation (TMAS) is an emerging non-invasive neuromodulation technique that may provide a novel non-pharmacological intervention strategy for Parkinson's disease (PD). PD is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc), leading to motor impairments such as bradykinesia, tremor, and rigidity. Increasing evidence indicates that mitochondrial dysfunction and impaired mitochondrial quality control are central mechanisms underlying dopaminergic neuronal loss. In particular, abnormalities in mitophagy and mitochondrial fission-fusion balance contribute substantially to oxidative stress, energy metabolic failure, and neuronal injury. At present, most clinical treatments for PD mainly alleviate symptoms but do not effectively halt disease progression. Therefore, exploring new interventions targeting the core pathological mechanisms is of considerable significance. This study aims to investigate whether TMAS can improve neural damage and motor dysfunction in PD mice by regulating mitophagy and the fission/fusion dynamic balance, thereby providing theoretical and experimental support for its application in PD treatment. MethodsMale C57BL/6 mice were used in this study. A PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days. After model induction, mice in the intervention group received TMAS once daily for 14 consecutive days, whereas the corresponding control group received sham stimulation. The stimulation target was positioned over the primary motor cortex (M1). Motor performance was evaluated using the pole test and the open-field test. To verify the activation effect of TMAS on the target cortical region, c-Fos immunohistochemistry was performed in the M1. To assess nigral dopaminergic neuronal injury, tyrosine hydroxylase (TH) immunohistochemistry was used to quantify TH-positive neurons in the SNc. Mitochondrial function was evaluated by measuring reactive oxygen species (ROS) levels and adenosine triphosphate (ATP) content in the SNc. Western blot was further performed to determine the expression of mitophagy-related proteins, including PINK1, Parkin, LC3-II, and p62, as well as mitochondrial dynamics-related proteins, including Drp1 and Opa1. ResultsTMAS significantly increased the number of c-Fos-positive cells in M1 (P<0.000 1), indicating effective activation of neurons in the targeted cortical region. Compared with the control group, MPTP-treated mice exhibited marked motor dysfunction, including a significant reduction in total distance traveled in the open-field test (P<0.000 1) and mean speed (P=0.000 1), as well as significant prolongation of turn time and total climbing time in the pole test (P<0.000 1). These behavioral impairments were accompanied by a substantial loss of TH-positive dopaminergic neurons in the SNc, whereas TMAS significantly increased TH-positive neuron survival (P<0.000 1). In parallel, MPTP induced a pronounced increase in ROS levels and a significant reduction in ATP content, indicating severe mitochondrial dysfunction and energy metabolism impairment (P<0.01). TMAS treatment significantly improved motor performance, as reflected by the reversal of MPTP-induced impairment in the open-field and pole tests, and significantly reduced ROS accumulation (P<0.01) while restoring ATP production (P<0.001). At the molecular level, MPTP markedly downregulated PINK1 and Parkin, decreased p62 expression, increased LC3-II accumulation, elevated Drp1 expression, and reduced Opa1 expression, whereas TMAS significantly reversed these abnormalities, suggesting restoration of mitophagy-related mitochondrial quality control and re-establishment of mitochondrial fission-fusion balance. Collectively, these findings indicate that TMAS ameliorates MPTP-induced neurotoxicity and restores mitochondrial homeostasis and energy metabolism. ConclusionTMAS effectively attenuates neural damage and improves motor dysfunction in MPTP-induced PD mice. Its neuroprotective effects are closely associated with multidimensional regulation of the mitochondrial quality control system, including restoration of PINK1/Parkin-mediated mitophagy and rebalancing of Drp1/Opa1-related mitochondrial dynamics. Rather than acting only as a symptomatic neuromodulatory intervention, TMAS may influence a key pathological axis of PD by improving mitochondrial homeostasis in SNc and protecting nigral dopaminergic neurons. These findings provide experimental evidence supporting TMAS as a promising non-invasive physical intervention for PD.

ObjectiveTranscranial magneto-acoustic stimulation (TMAS) is an emerging non-invasive neuromodulation technique that may provide a novel non-pharmacological intervention strategy for Parkinson's disease (PD). PD is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc), leading to motor impairments such as bradykinesia, tremor, and rigidity. Increasing evidence indicates that mitochondrial dysfunction and impaired mitochondrial quality control are central mechanisms underlying dopaminergic neuronal loss. In particular, abnormalities in mitophagy and mitochondrial fission-fusion balance contribute substantially to oxidative stress, energy metabolic failure, and neuronal injury. At present, most clinical treatments for PD mainly alleviate symptoms but do not effectively halt disease progression. Therefore, exploring new interventions targeting the core pathological mechanisms is of considerable significance. This study aims to investigate whether TMAS can improve neural damage and motor dysfunction in PD mice by regulating mitophagy and the fission/fusion dynamic balance, thereby providing theoretical and experimental support for its application in PD treatment. MethodsMale C57BL/6 mice were used in this study. A PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days. After model induction, mice in the intervention group received TMAS once daily for 14 consecutive days, whereas the corresponding control group received sham stimulation. The stimulation target was positioned over the primary motor cortex (M1). Motor performance was evaluated using the pole test and the open-field test. To verify the activation effect of TMAS on the target cortical region, c-Fos immunohistochemistry was performed in the M1. To assess nigral dopaminergic neuronal injury, tyrosine hydroxylase (TH) immunohistochemistry was used to quantify TH-positive neurons in the SNc. Mitochondrial function was evaluated by measuring reactive oxygen species (ROS) levels and adenosine triphosphate (ATP) content in the SNc. Western blot was further performed to determine the expression of mitophagy-related proteins, including PINK1, Parkin, LC3-II, and p62, as well as mitochondrial dynamics-related proteins, including Drp1 and Opa1. ResultsTMAS significantly increased the number of c-Fos-positive cells in M1 (P<0.000 1), indicating effective activation of neurons in the targeted cortical region. Compared with the control group, MPTP-treated mice exhibited marked motor dysfunction, including a significant reduction in total distance traveled in the open-field test (P<0.000 1) and mean speed (P=0.000 1), as well as significant prolongation of turn time and total climbing time in the pole test (P<0.000 1). These behavioral impairments were accompanied by a substantial loss of TH-positive dopaminergic neurons in the SNc, whereas TMAS significantly increased TH-positive neuron survival (P<0.000 1). In parallel, MPTP induced a pronounced increase in ROS levels and a significant reduction in ATP content, indicating severe mitochondrial dysfunction and energy metabolism impairment (P<0.01). TMAS treatment significantly improved motor performance, as reflected by the reversal of MPTP-induced impairment in the open-field and pole tests, and significantly reduced ROS accumulation (P<0.01) while restoring ATP production (P<0.001). At the molecular level, MPTP markedly downregulated PINK1 and Parkin, decreased p62 expression, increased LC3-II accumulation, elevated Drp1 expression, and reduced Opa1 expression, whereas TMAS significantly reversed these abnormalities, suggesting restoration of mitophagy-related mitochondrial quality control and re-establishment of mitochondrial fission-fusion balance. Collectively, these findings indicate that TMAS ameliorates MPTP-induced neurotoxicity and restores mitochondrial homeostasis and energy metabolism. ConclusionTMAS effectively attenuates neural damage and improves motor dysfunction in MPTP-induced PD mice. Its neuroprotective effects are closely associated with multidimensional regulation of the mitochondrial quality control system, including restoration of PINK1/Parkin-mediated mitophagy and rebalancing of Drp1/Opa1-related mitochondrial dynamics. Rather than acting only as a symptomatic neuromodulatory intervention, TMAS may influence a key pathological axis of PD by improving mitochondrial homeostasis in SNc and protecting nigral dopaminergic neurons. These findings provide experimental evidence supporting TMAS as a promising non-invasive physical intervention for PD.

Objective To evaluate the safety and efficacy of total arterial off-pump coronary artery bypass grafting (OPCABG) using a left internal thoracic artery (LITA) combined with bilateral radial arteries (RAs). Methods We retrospectively analyzed the clinical data of patients with severe multi-vessel coronary artery disease who underwent total arterial OPCABG with a LITA and bilateral RAs at Sichuan Provincial People’s Hospital from November 2020 to April 2023. Results A total of 24 patients were included, comprising 23 males and 1 female, with a mean age of (53.63±4.33) years. The New York Heart Association (NYHA) functional class was Ⅱ to Ⅲ. The mean number of distal anastomoses was 3.17±0.38. A Y-graft was constructed in 12 patients and sequential grafting was performed in 4 patients. Concomitant procedures included coronary endarterectomy in 1 patient, intra-aortic balloon pump (IABP) implantation in 10 patients, and thymoma resection in 1 patient. The mean operative time was (308.13±30.39) min, mechanical ventilation time was (15.42±7.42) h, ICU stay was (46.08±27.32) h, and postoperative hospital stay was (11.71±1.90) d. There were no in-hospital deaths. Postoperative complications included one patient of acute renal failure and one patient of cerebral infarction. Pre-discharge color Doppler echocardiography revealed that the left ventricular end-diastolic diameter was significantly smaller than before surgery (P<0.05), while the left ventricular ejection fraction and fractional shortening were significantly higher (P<0.05). Coronary computed tomography angiography (CTA) showed that all arterial grafts were patent. During a mean follow-up of (14.58±8.75) months, no patients experienced angina recurrence or mortality. Repeat coronary CTA or angiography in 16 patients one year postoperatively confirmed that all arterial grafts remained patent. Conclusion Total arterial OPCABG using a LITA and bilateral RAs is a safe and effective treatment for patients with severe multi-vessel coronary artery disease. For high-risk patients, intraoperative IABP support is recommended.

Objective: To investigate the association between occupational stress and health-related quality of life (HRQoL) among grassroots medical personnels, so as to provide the reference for improving their physical and mental well-being. Methods: From March to May 2024, medical staff from nine street community health service centers in Liangxi District, Wuxi City, Jiangsu Province were selected by a convenient sampling method. Basic information was collected through questionnaire surveys. Occupational stress was assessed using the Core Occupational Stress Measurement Scale. Health utility value and the Visual Analog Scale (EQ-VAS) score were investigated using the European Quality of Life Five-Dimension Five-Level (EQ-5D-5L) questionnaire. The association between occupational stress and HRQoL was analyzed using multiple linear regression model. Results: A total of 909 individuals were surveyed, including 141 males (15.51%) and 768 females (84.49%). The average occupational stress score was (24.41±9.45) points. The average health utility value was (0.96±0.07), with 372 individuals (40.92%) experiencing health problems in at least one dimension. The primarily problems were pain/discomfort and anxiety/depression, with 249 (27.39%) and 265 (29.15%) individuals, respectively. The average EQ-VAS score was (86.62±13.84) points. Multiple linear regression analysis revealed that occupation (nurses, β'=0.101; pharmacists, β'=0.101; medical technicians, β'=0.090), professional title (intermediate, β'=-0.079; associate senior, β'=-0.081; senior, β'=-0.101), and occupational stress (β'=-0.288) were influencing factors for health utility value. Occupation (nurses, β'=0.087; pharmacists, β'=0.146; medical technicians, β'=0.073) and occupational stress (β'=-0.226) were influencing factors for EQ-VAS score. After adjusting for variables such as gender, age, educational level, occupation, professional title, work experience, and monthly income, grassroots medical personnels with higher occupational stress score had lower health utility values (β'=-0.296) and EQ-VAS score (β'=-0.237). Conclusions Occupational stress can reduce the HRQoL among grassroots medical personnels. It is recommended to regularly assess occupational stress levels and intervene early to address their psychological and physical health issues.

AIM To study the chemical constituents from Gymnema tingens Spreng.and their in vitro hypoglycemic activity.METHODS The 70％ethanol extract was isolated and purified by macroporous resin,silica gel,sephadex LH-20,and semi-preparative HPLC,then the structures of obtained compounds were identified by physicochemical propeties and spectral data.The in vitro hypoglycemic activity was evaluated by glucose uptake test in L6 cells.RESULTS Seventeen compounds were isolated and identified as 7-desoxyneocynapanogenin A(1),glaucogenin(2),cynatratoside A(3),atratcynoside F(4),(+)-lyoniresinol(5),(+)-lyoniresinol 3-O-α-D-rhamnopyranoside-(1→6)-β-D-glucopyranoside(6),fernandoside(7),3,4-dimethoxy-phenyl-1-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside(8),khaephuoside A(9),khaephuoside B(10),3,4,5-trimethoxy-phenyl-O-β-D-glucopyranoside(11),liquiritigenin(12),7,3'-dihydroxy-flavanone-4'-O-β-D-glucopyranoside(13),pinoresinol(14),syringaldehyde(15),(+)-1-hydroxy-pinoresinol-1-β-D-glucopyranoside(16),β-amyrin(17).Compounds 2-5、7、9、10、12、17 could promote the glucose uptake in L6 cells.CONCLUSION Compound 1 is a new compound,and 2-9、11-13、15-17 are isolated from this plant for the first time.Compounds 2-5、7、9、10、12、17 have good hypoglycemic activity.

OBJECTIVE To explore the clinical characteristics of the nontuberculous Mycobacteria pulmonary dis-ease(NTMPD)patients with previous pulmonary tuberculosis(PPTB)and analyze the clinical difference from the recurrence of pulmonary tuberculosis.METHODS By means of retrospective survey,the patients who were diag-nosed with NTMPD and recurrent pulmonary tuberculosis in Wuhan Pulmonary Hospital from Mar.2021 to Oct.2023 were recruited as the research subjects,a total of 395 patients with NTMPD were enrolled in the study and were divided into the PPTB-NTMPD group with 92 cases and the NPPTB-NTMPD group with 303 cases according to the history of PPTB.The baseline data,clinical symptoms,imaging findings,underlying diseases,pulmonary diseases,and species of nontuberculous Mycobacteria(NTM)were observed and compared.Totally 92 patients with recurrent pulmonary tuberculosis were randomly screened and assigned as the recurrent pulmonary tuberculo-sis group in a 1:1 ratio by matching the PPTB-NTMPD group with the gender and age.The major clinical charac-teristics were compared between the two groups.The 92 patients with PPTB-NTMPD were divided into the 1-10 years group with 40 cases,the 10-30 years group with 37 cases,and the more than 30 years group with 15 cases according to the interval between the initial diagnosis of pulmonary tuberculosis and the diagnosis of NTMPD.The major clinical characteristics were compared among the groups.RESULTS The age was(64.21±10.71)years old in the PPTB-NTMPD group,(60.26±11.83)years old in the NPPTB-NTMPD group(t=3.020,P=0.003).The proportion of patients with body mass index less than 18.5 kg/m2 was 59.78％in the PPTB-NTMPD group,41.25％in the NPPTB-NTMPD group(x2=6.155,P=0.013);the proportion of patients with cough was 77.17％in the PPTB-NTMPD group,65.68％in the NPPTB-NTMPD group(x2=4.313,P=0.038);the inci-dence of cavitary shadow was 50.00％in the PPTB-NTMPD group,35.31％in the NPPTB-NTMPD group(x2=6.414,P=0.011);the incidence of emphysema and pulmonary bullae was 29.35％in the PPTB-NTMPD group,12.87％in the NPPTB-NTMPD group(x2=13.766,P＜0.001);the incidence of chronic obstructive pulmonary disease(COPD)was 22.83％in the PPTB-NTMPD group,14.19％in the NPPTB-NTMPD group(x2=3.875,P=0.049);the incidence of damaged lung was 9.78％in the PPTB-NTMPD group,2.97％in the NPPTB-NT-MPD group(x2=7.530,P=0.014);there were significant differences.Mycobacterium intracellulare and Myco-bacterium abscessus were the predominant species of NTM in both the PPTB-NTMPD group and the NPPTB-NT-MPD group,there was no significant difference in the distribution of NTM species between the two groups of pa-tients.The incidence of patch shadow of the PPTB-NTMPD group was lower than that of the recurrent pulmonary tuberculosis group(P＜0.05),the incidence of bronchiectatic shadow of the PPTB-NTMPD group was higher than that of the recurrent pulmonary tuberculosis group(P＜0.05).There were significant differences in the age,incidence of pleural thickening and incidence of COPD among the patients with different time intervals between ini-tial diagnosis of pulmonary tuberculosis and the diagnosis of NTMPD in the PPTB-NTMPD group(P＜0.05).CONCLUSIONS The previous pulmonary tuberculosis mainly affect the body mass index less than 18.5 kg/m2 and the post-tuberculosis pulmonary diseases such as cough,pulmonary cavity,emphysema,pulmonary bullae,COPD and damaged lung of the NTMPD patients.The NTMPD patients with previous pulmonary tuberculosis are more likely to have bronchiectasia than the patients with recurrent tuberculosis.It is necessary for the clinicians to attach great importance.

OBJECTIVE To observe the effect of Shixiang plaster on promoting the wound healing of diabetic foot ulcer.METHODS Totally 50 male SPF grade SD rats were prepared to establish the diabetic models by feeding with high glucose and high fat forage and intraperitoneal injection of streptozotocin,the rats models that were es-tablished successfully were randomly divided into the model group,the Shixiang plaster group and the Kangfuxin solution group.The models of diabetic ulcers were established.The Shixiang plaster group was treated with exter-nal Shixiang plaster,the Kangfuxin solution group was given external Kangfuxin solution,and the model group was treated with coverage with sterile gauze.The wound healing status of the rats was observed,the wound tis-sues were collected for bacterial culture and hematoxylin-eosin(HE)staining after drug administration for 14 and 28 days,respectively.The expression levels of nuclear factor-red cell-2-related factor 2(Nrf-2),heme oxygenase-1(HO-1),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)and vascular endothelial growth factor(VEGF)were detected by immunohistochemistry(IHC),the expression levels of Nrf-2 and HO-1 were detected with the use of Western Blot,and the levels of serum malondialdehyde(MDA),superoxide dismutase(SOD)and reactive oxygen species(ROS)were detected by enzyme-linked immunosorbent assay(ELISA).RESULTS After the drug administration for 14 and 28 days,the wound healing rates of the Shixiang plaster group were(62.15±3.82)％and(81.68±3.83)％,respectively,higher than(47.14±2.80)％and(69.96±6.49)％of the Kangfuxin solu-tion group and(29.14±9.52)％and(57.91±6.63)％of the model group,and there were significant differences(F=21.716,12.626,P=0.002,0.007).The bacterial colony counts of the Shixiang plaster group were less than those of the Kangfuxin solution group and the model group after the drug administration for 14 and 28 days(P＜0.05).The result of HE staining showed that the Shixiang plaster group had a better wound healing.The result of IHC indicated that the expression levels of Nrf-2,HO-1 and VEGF of the Kangfuxin solution group and the Shix-iang plaster group were up-regulated after the drug administration for 28 days,while the expression levels of TNF-α and IL-6 were down-regulated.The expression levels of Nrf-2 and HO-1 proteins of the Shixiang plaster group were higher than those of the Kangfuxin solution group and the model group after the drug administration for 14 and 28 days,the levels of serum MDA and ROS of the Shixiang plaster group were lower than those of the Kangfuxin solution group and the model group,and the serum SOD level of the Shixiang plaster group was higher than that of the model group(P＜0.05).CONCLUSIONS Shixiang plaster can effectively promote the wound heal-ing of the rats with diabetic foot ulcers and reduce the bacterial colony counts of wound surfaces.The mechanism may be associated with the alleviation of oxidative stress injury by mediating the Nrf-2/HO-1 signaling pathways,promotion of angiogenesis and inhibition of excessive inflammatory reactions.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.