Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

Objective:Hypoxia is a common pathological phenomenon,usually caused by insufficient oxygen supply or inability to use oxygen effectively.Hydroxylated and methoxylated flavonoids have significant anti-hypoxia activity.This study aims to explore the synthesis,antioxidant and anti-hypoxia activities of 6-hydroxygenistein(6-OHG)and its methoxylated derivatives. Methods:The 6-OHG and its methoxylated derivatives,including 4',6,7-trimethoxy-5-hydroxyisoflavone(compound 3),4',5,6,7-tetramethoxyisoflavone(compound 4),4',6-imethoxy-5,7-dihydroxyisoflavone(compound 6),and 4'-methoxy-5,6,7-trihydroxyisoflavone(compound 7),were synthesized by methylation,bromination,methoxylation,and demethylation using biochanin A as raw material.The structure of these products were characterized by 1hydrogen-nuclear magnetic resonance spectroscopy(1H-NMR)and mass spectrometry(MS).The purity of these compounds was detected by high pressure chromatography(HPLC).The antioxidant activity in vitro was investigated by 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)free radical scavenging assay.PC12 cells were divided into a normal group,a hypoxia model group,rutin(1×10-9-1×10-5 mol/L)groups,and target compounds(1×10-9-1×10-5 mol/L)groups under normal and hypoxic conditions.Cell viability was detected by cell counting kit-8(CCK-8)assay,the target compounds with excellent anti-hypoxia activity and the drug concentration at the maximum anti-hypoxia activity were screened.PC12 cells were treated with the optimal concentration of the target compound or rutin with excellent anti-hypoxia activity,and the cell morphology was observed under light microscope.The apoptotic rate was determined by flow cytometry,and the expressions of hypoxia inducible factor-1α(HIF-1α)and vascular endothelial growth factor(VEGF)were detected by Western blotting. Results:The structure of 6-OHG and its 4 methylated derivatives were correct,and the purity was all more than 97%.When the concentration was 4 mmol/L,the DPPH free radical removal rates of chemical compounds 7 and 6-OHG were 81.16%and 86.94%,respectively,which were higher than those of rutin,the positive control.The removal rates of chemical compounds 3,4,and 6 were all lower than 20%.Compared with the normal group,the cell viability of the hypoxia model group was significantly decreased(P<0.01).Compared with the hypoxia model group,compounds 3,4,and 6 had no significant effect on cell viability under hypoxic conditions.At all experimental concentrations,the cell viability of the 6-OHG group was significantly higher than that of the hypoxia model group(all P<0.05).The cell viability of compound 7 group at 1×10-7 and 1×10-6 mol/L was significantly higher than that of the hypoxia model group(both P<0.05).The anti-hypoxia activity of 6-OHG and compound 7 was excellent,and the optimal drug concentration was 1×10-6 and 1×10-7 mol/L.After PC12 cells was treated with 6-OHG(1×10-6 mol/L)and compound 7(1×10-7 mol/L),the cell damage was reduced,the apoptotic rate was significantly decreased(P<0.01),and the protein expression levels of HIF-1α and VEGF were significantly decreased in comparison with the hypoxia model group(both P<0.01). Conclusion:The optimized synthesis route can increase the yield of 6-OHG and obtain 4 derivatives by methylation and selective demethylation.6-OHG and compound 7 have excellent antioxidant and anti-hypoxia activities,which are related to the structure of the A-ring ortho-triphenol hydroxyl group in the molecule.

ObjectiveTo explore the relationship between five-state personality and Cattell's 16 personality factors. MethodsA total of 913 students recruited from Beijing University of Chinese Medicine from November 2020 to January 2021 were assessed by using the Five-state Personality Test Form and the 16 Personality Factors Questionnaire （16PF）. The five-state personality scores were compared with national norms and gender differences were examined. Additionally， a structural equation model was established and the model fit was assessed using comparative fit index （CFI）， Tucker-Lewis index （TLI）， and root mean square error of approximation （RMSEA）. The five-state personality （Taiyang， Shaoyang， Yin-yang balance， Shaoyin and Taiyin） was used as individual outcome variables while the 16PF factors was employed as predictor variables. Based on standardized parameter estimation results， we explored the relationships between the five-state personality and 16PF. ResultsA total of 913 students were recruited， and 756 valid samples were obtained after excluding unqualified questionnaires. Among these， the scores of Taiyang， Shaoyang and Taiyin in the 756 school students were significantly lower than the national norms， while the scores of Yin-yang balance was significantly higher （P＜0.05 or P＜0.01）. The scores of Taiyang， Shaoyang， Yin-yang balance and Shaoyin were significantly higher than in males compared to females （P＜0.05 or P＜0.01）. Regarding the relationship between the dimensions of five-state personality and 16PF， the model demonstrated a good fit with CFI and TLI values of 0.993 and 0.980， respectively， and an RMSEA value of 0.027. The 16PF factors， including dominance， social boldness， vigilance， rule-consciousness， tension， and emotional stability， positively predicted the Taiyang personality traits， while privateness and apprehension negatively predicted the Taiyang personality traits （P＜0.05 or P＜0.01）. For Shaoyang personality traits， factors such as liveliness， social boldness， dominance， and tension positively predicted them， while rule-consciousness， apprehension， and privateness negatively predicted Shaoyang perso-nality traits （P＜0.05 or P＜0.01）. In the case of Yin-yang balance personality traits， perfectionism， rule-consciousness， emotional stability， and self-reliance positively predicted them， while apprehension negatively predicted Yin-yang balance personality traits （P＜0.05 or P＜0.01）. Regarding Shaoyin personality traits， perfectionism， emotional stability， self-reliance， rule-consciousness， and vigilance positively predicted them， while dominance， social boldness， and liveliness negatively predicted Shaoyin personality traits （P＜0.01）. Apprehension， tension， vigilance， and self-reliance positively predicted Taiyin personality traits， while social boldness， rule-consciousness， and intelligence negatively predicted Taiyin personality traits （P＜0.05 or P＜0.01）. ConclusionThere is a significant correlation between five-state personality test and 16PF with 16PF factors capable of predicting five-state personality factors. The five-state personality demonstrates scientific validity and effectiveness.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.

Objective:To investigate the clinical characteristics and risk factors of frailty syndrome in elderly patients undergoing maintenance hemodialysis (MHD) and the effect of frailty syndrome on all-cause mortality.Methods:This was a prospective cohort study. MHD patients aged≥60 years in 5 hemodialysis centers in Beijing from April to June 2017 were selected as the study subjects. Baseline data were collected and compared, and the patients were then classified into non-frailty, pre-frailty and frailty syndrome groups according to the Fried criteria and followed up until June 2018. The end point event was all-cause death. Multivariate logistic regression was used to analyze the independent risk factors of frailty syndrome. Kaplan-Meier survival analysis was used to compare the difference in the cumulative survival rate among the 3 groups. A multivariate Cox regression model was used to analyze the independent risk factors of all-cause mortality.Results:A total of 204 patients aged (71.65±5.89) years (60-81 years) were enrolled into this study, including 123 males (60.29%), 147 patients (72.06%) in the frailty syndrome group, 41 patients (20.10%) in the pre-frailty group, and 16 patients (7.84%) in the non-frailty group. Patients with frailty syndrome tended to be older, longer dialysis vintage, a higher proportion of diabetes, lower urea clearance index (Kt/V) and lower serum albumin level (all P<0.05). Multivariate Logistic regression showed that factors independently associated with frailty syndrome included age ( OR=1.393, 95% CI 1.241-1.563, P<0.001), history of diabetes ( OR=3.610, 95% CI 1.262-10.327, P=0.017), dialysis vintage ( OR=1.011, 95% CI 1.002-1.020, P=0.019), Kt/V ( OR=0.711, 95% CI 0.516-0.979, P=0.037), serum albumin ( OR=0.754, 95% CI 0.644-0.882, P<0.001) and intact parathyroid hormone (iPTH, OR=1.344, 95% CI 1.024-1.763, P=0.033). Kaplan-Meier survival analysis showed that the cumulative survival rate in frailty syndrome group was significantly lower than those of pre-frailty (Log-rank χ2=7.265, P=0.007) and non-frailty groups (Log-rank χ2=5.238, P=0.022). Multivariate Cox regression analysis indicated that frailty syndrome ( HR=3.832, 95% CI 1.116-13.157, P=0.033), age ( HR=1.074, 95% CI 1.014-1.136, P=0.014), history of diabetes ( HR=2.009, 95% CI 1.067-3.784, P=0.031), cognitive impairment (Montreal cognitive assessment<26, HR=2.627, 95% CI 1.142-6.042, P=0.023), Kt/V ( HR=0.701, 95% CI 0.545-0.902, P=0.006), serum albumin ( HR=0.891, 95% CI 0.806-0.986, P=0.025) and iPTH ( HR=1.226, 95% CI 1.100-1.367, P<0.001) were independently associated with all-cause mortality. Conclusions:The prevalence of frailty syndrome in elderly patients undergoing hemodialysis is high. Ageing, diabetes history, long dialysis vintage, low levels of Kt/V and serum albumin, and elevated iPTH level are independent risk factors for frailty syndrome in such patients. Frailty syndrome is independently associated with an increased risk of all-cause mortality.