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 investigate the occurrence of malignancy in psoriatic arthritis (PsA) patients, and further explore the factors related to malignancy.Methods:Based on the PsA prospective follow-up cohort (PKUPsA-PC) in our center, we collected the demographics and clinical characteristics of patients who visited from January 2016 to January 2024, especially those regarding the malignant tumor. The clinical characteristics of patients with and without malignant tumor were compared through the method of non-parametric tests and chi-square tests. Multivariate logistic regression was applied to analyze the factors related to malignant tumors.Results:Three hundred and eighty two patients with PsA were enrolled. The median follow-up duration was 6.0 (2.8,12.8) years. Twenty two (5.8%) patients were complicated with malignant tumors. The median age of confirmed tumors was 56.4 (45.8, 67.3) years. Among them, 14 (63.6%) patients were female, and 16 (72.7%) patients had malignant tumors after the diagnosis of PsA. As for the tumor types, solid tumors were great majority (21 cases, 95.5%), including breast cancer (7 cases), urinary system tumors (5 cases), skin cancer (3 cases), colorectal/rectal cancer (2 cases), and thyroid cancer, liver cancer, endometrial carcinoma in situ, retroperitoneal malignant tumor (1 case respectively). There was only 1 (4.5%) patient with hematological tumor (chronic lymphocytic leukemia). Compared with patients without malignant tumors, PsA patients with malignancy had a higher proportion of women (63.6% vs. 40.8%, χ2=4.42, P=0.035), older age [56.4 (45.8, 67.3)years vs. 47.0 (36.0, 56.6) years, Z=-2.94, P=0.003], had a longer duration of psoriasis [20.0 (11.2, 33.5)years vs. 14.0 (6.0, 23.0) years, Z=-2.02, P=0.043], a longer duration of arthritis [8.0 (4.0, 17.0)years vs. 3.0 (1.0, 7.0) years, Z=-2.65, P=0.008], and a higher proportion of HLA-B27 positivity (25.0% vs. 4.4%, χ2=3.98, P=0.046). Age[ OR(95% CI)=1.056(1.008, 1.107), P=0.023], duration of PsA [ OR(95% CI)=1.051( 1.068, 1.106), P=0.010], and HLA-B27 positivity [ OR(95% CI)=5.086(1.278, 20.238), P=0.021] were the factors related to the occurrence of malignancy in PsA patients. Conclusion:Malignancy is not rare in PsA patients. Breast cancer, urinary system tumors and skin cancer are relatively common. PsA patients with older age, longer duration of PsA and positive HLA-B27 are more likely to have malignancy, which arouses more alert.

Objective:To explore the differences in the CVD risk and lipid profiles in psoriatic arthritis (PsA) patients with different disease activity and investigate lipid management status in Chinese patients with PsA.Methods:Patients were enrolled from PKUPsA-PC cohort in Peking University First Hospital from January 2016 to January 2024. Data were collected at their first visit, including disease activity score, lipid profiles and treatment. Two modified CVD risk prediction models (modified China-PAR and modified FRS-CVD) were applied to predict the CVD risk over 10 years. All enrolled patients were subsequently stratified into low, intermediate and high-risk groups. The status of lipid target achievement was assessed based on lipid management recommendations proposed by prediction models. In addition, DAPSA was used to stratify PsA patients into remission, low, moderate and high-disease activity groups, and the differences in CVD risk and lipid profiles among PsA patients with different disease activity status were explored. The t test was used for comparison between 2 groups for measures that conformed to normal distribution; the Mann-Whitney U test was used for comparison between 2 groups for measures that were skewed; and the chi-square test was used for comparison between 2 groups for categorical data.Results:Three hundred and seven PsA patients were included in this study. They were aged 47 (36, 57) years with 121 (39.4%) female, disease duration of skin lesions of 14 (7, 23) years and disease duration of PsA for 3 (1, 8) years. There were 148 (48.2%) patients with dyslipidemia, and 38 (25.7%) of them were receiving lipid lowering drugs. By the modified China-PAR model, there were 174 (56.7%), 76 (24.8%) and 57 (18.5%) in the low-, moderate- and high-risk groups. By the modified FRS-CVD model, there were 173 (56.4%), 58 (18.9%) and 76 (24.7%) patients in the corresponding groups. According to the recommendations for lipid management based on FRS-CVD model, 80 (26.1%) patients did not achieve the target of lipid profile, including 9/174 (5.2%) in the modified model low-risk group, 20/76 (26.3%) in the intermediate-risk group, and 51/57 (89.5%) in the high-risk group, but there were only 12 (15.0%) patients receiving statin therapy. Compared with the remission and low disease activity groups, patients in the moderate-to-high disease activity group were older [50 (37, 60) years vs. 43 (35, 55) years, Z=-2.42, P=0.016]; had a higher proportion of hypertension (30.3% vs. 15.0%, χ2=9.60, P=0.002); and had lower HDL-C levels [1.1 (0.9, 1.3) mmol/L vs. 1.2 (1.0, 1.4) mmol/L, Z=-3.18, P=0.001]. Under the modified China-PAR and modified FRS-CVD risk prediction models, a higher proportion of patients with high disease activity in PsA were stratified at high 10-year CVD risk compared with the remission and low disease activity groups (29.5% vs. 19.6%, χ2=3.81, P=0.005) and (23.5% vs. 12.4%, χ2=6.00, P=0.014). Conclusion:Nearly half of the PsA patients are at medium-high risk to CVD. CVD risk is significantly higher in patients with moderate to high disease activity than in patients with remission and low disease activity. HDL-c levels are lower in patients with high disease activity. Nevertheless a quarter of patients did not achieve the target of lipid profile, and few patients are receiving statin. More attention should be paid to CVD risk evaluation and lipid management as a part of treat-to-target strategy to improve the prognosis.

Objective:To explore the differences in the CVD risk and lipid profiles in psoriatic arthritis (PsA) patients with different disease activity and investigate lipid management status in Chinese patients with PsA.Methods:Patients were enrolled from PKUPsA-PC cohort in Peking University First Hospital from January 2016 to January 2024. Data were collected at their first visit, including disease activity score, lipid profiles and treatment. Two modified CVD risk prediction models (modified China-PAR and modified FRS-CVD) were applied to predict the CVD risk over 10 years. All enrolled patients were subsequently stratified into low, intermediate and high-risk groups. The status of lipid target achievement was assessed based on lipid management recommendations proposed by prediction models. In addition, DAPSA was used to stratify PsA patients into remission, low, moderate and high-disease activity groups, and the differences in CVD risk and lipid profiles among PsA patients with different disease activity status were explored. The t test was used for comparison between 2 groups for measures that conformed to normal distribution; the Mann-Whitney U test was used for comparison between 2 groups for measures that were skewed; and the chi-square test was used for comparison between 2 groups for categorical data.Results:Three hundred and seven PsA patients were included in this study. They were aged 47 (36, 57) years with 121 (39.4%) female, disease duration of skin lesions of 14 (7, 23) years and disease duration of PsA for 3 (1, 8) years. There were 148 (48.2%) patients with dyslipidemia, and 38 (25.7%) of them were receiving lipid lowering drugs. By the modified China-PAR model, there were 174 (56.7%), 76 (24.8%) and 57 (18.5%) in the low-, moderate- and high-risk groups. By the modified FRS-CVD model, there were 173 (56.4%), 58 (18.9%) and 76 (24.7%) patients in the corresponding groups. According to the recommendations for lipid management based on FRS-CVD model, 80 (26.1%) patients did not achieve the target of lipid profile, including 9/174 (5.2%) in the modified model low-risk group, 20/76 (26.3%) in the intermediate-risk group, and 51/57 (89.5%) in the high-risk group, but there were only 12 (15.0%) patients receiving statin therapy. Compared with the remission and low disease activity groups, patients in the moderate-to-high disease activity group were older [50 (37, 60) years vs. 43 (35, 55) years, Z=-2.42, P=0.016]; had a higher proportion of hypertension (30.3% vs. 15.0%, χ2=9.60, P=0.002); and had lower HDL-C levels [1.1 (0.9, 1.3) mmol/L vs. 1.2 (1.0, 1.4) mmol/L, Z=-3.18, P=0.001]. Under the modified China-PAR and modified FRS-CVD risk prediction models, a higher proportion of patients with high disease activity in PsA were stratified at high 10-year CVD risk compared with the remission and low disease activity groups (29.5% vs. 19.6%, χ2=3.81, P=0.005) and (23.5% vs. 12.4%, χ2=6.00, P=0.014). Conclusion:Nearly half of the PsA patients are at medium-high risk to CVD. CVD risk is significantly higher in patients with moderate to high disease activity than in patients with remission and low disease activity. HDL-c levels are lower in patients with high disease activity. Nevertheless a quarter of patients did not achieve the target of lipid profile, and few patients are receiving statin. More attention should be paid to CVD risk evaluation and lipid management as a part of treat-to-target strategy to improve the prognosis.

Objective:To investigate the occurrence of malignancy in psoriatic arthritis (PsA) patients, and further explore the factors related to malignancy.Methods:Based on the PsA prospective follow-up cohort (PKUPsA-PC) in our center, we collected the demographics and clinical characteristics of patients who visited from January 2016 to January 2024, especially those regarding the malignant tumor. The clinical characteristics of patients with and without malignant tumor were compared through the method of non-parametric tests and chi-square tests. Multivariate logistic regression was applied to analyze the factors related to malignant tumors.Results:Three hundred and eighty two patients with PsA were enrolled. The median follow-up duration was 6.0 (2.8,12.8) years. Twenty two (5.8%) patients were complicated with malignant tumors. The median age of confirmed tumors was 56.4 (45.8, 67.3) years. Among them, 14 (63.6%) patients were female, and 16 (72.7%) patients had malignant tumors after the diagnosis of PsA. As for the tumor types, solid tumors were great majority (21 cases, 95.5%), including breast cancer (7 cases), urinary system tumors (5 cases), skin cancer (3 cases), colorectal/rectal cancer (2 cases), and thyroid cancer, liver cancer, endometrial carcinoma in situ, retroperitoneal malignant tumor (1 case respectively). There was only 1 (4.5%) patient with hematological tumor (chronic lymphocytic leukemia). Compared with patients without malignant tumors, PsA patients with malignancy had a higher proportion of women (63.6% vs. 40.8%, χ2=4.42, P=0.035), older age [56.4 (45.8, 67.3)years vs. 47.0 (36.0, 56.6) years, Z=-2.94, P=0.003], had a longer duration of psoriasis [20.0 (11.2, 33.5)years vs. 14.0 (6.0, 23.0) years, Z=-2.02, P=0.043], a longer duration of arthritis [8.0 (4.0, 17.0)years vs. 3.0 (1.0, 7.0) years, Z=-2.65, P=0.008], and a higher proportion of HLA-B27 positivity (25.0% vs. 4.4%, χ2=3.98, P=0.046). Age[ OR(95% CI)=1.056(1.008, 1.107), P=0.023], duration of PsA [ OR(95% CI)=1.051( 1.068, 1.106), P=0.010], and HLA-B27 positivity [ OR(95% CI)=5.086(1.278, 20.238), P=0.021] were the factors related to the occurrence of malignancy in PsA patients. Conclusion:Malignancy is not rare in PsA patients. Breast cancer, urinary system tumors and skin cancer are relatively common. PsA patients with older age, longer duration of PsA and positive HLA-B27 are more likely to have malignancy, which arouses more alert.

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 investigate the relationship between intramuscular adipose tissue index (IATI) calculated from computed tomography images at transverse process of the first lumbar and all-cause mortality in maintenance dialysis patients, and to provide a reference for improving the prognosis in these patients.Methods:It was a multicenter retrospective cohort study. The clinical data of patients who received maintenance hemodialysis or peritoneal dialysis treatment from January 1, 2017 to December 31, 2019 in 4 grade Ⅲ hospitals including Zhongda Hospital Affiliated to Southeast University, Taizhou People's Hospital Affiliated to Nanjing Medical University, Affiliated Hospital of Yangzhou University, and the Third Affiliated Hospital of Soochow University were retrospectively collected. IATI was calculated by low attenuation muscle (LAM) density/skeletal muscle density. The receiver-operating characteristic curve was used to determine the optimal cut-off value of IATI, and the patients were divided into high IATI group and low IATI group according to the optimal cut-off value. The differences of baseline clinical data and measurement parameters of the first lumbar level between the two groups were compared. The follow-up ended on December 23, 2022. The endpoint event was defined as all-cause mortality within 3 years. Kaplan-Meier survival curve and log-rank test were used to analyze the survival rates and the differences between the two groups. Multivariate Cox regression analysis models were used to analyze the association between IATI and the risk of all-cause mortality in maintenance dialysis patients. Multivariate logistic regression analysis model was used to analyze the influencing factors of high IATI.Results:A total of 478 patients were eligibly recruited in this study, with age of (53.55±13.19) years old and 319 (66.7%) males, including 365 (76.4%) hemodialysis patients and 113 (23.6%) peritoneal dialysis patients. There were 376 (78.7%) patients in low IATI (<0.42) group and 102 (21.3%) patients in high IATI (≥0.42) group. The proportion of age ≥ 60 years old ( χ2=24.746, P<0.001), proportion of diabetes mellitus ( χ2=5.570, P=0.018), fasting blood glucose ( t=-2.145, P=0.032), LAM density ( t=-3.735, P<0.001), LAM index ( t=-7.072, P<0.001), and LAM area/skeletal muscle area ratio ( Z=-9.630, P<0.001) in high IATI group were all higher than those in low IATI group, while proportion of males ( χ2=11.116, P<0.001), serum albumin ( Z=2.708, P=0.007) and skeletal muscle density ( t=12.380, P<0.001) were lower than those in low IATI group. Kaplan-Meier survival analysis showed that the 3-years overall survival rate of low IATI group was significantly higher than that in high IATI group (Log-rank χ2=19.188, P<0.001). Multivariate Cox regression analysis showed that IATI<0.42 [<0.42/≥0.42, HR(95% CI): 0.50 (0.31-0.83), P=0.007] was an independent protective factor of all-cause mortality, and age ≥60 years old [ HR (95% CI): 2.61 (1.60-4.23), P<0.001], diabetes mellitus [ HR (95% CI): 1.71 (1.06-2.78), P=0.029] and high blood neutrophil/lymphocyte ratio [ HR (95% CI): 1.04 (1.00-1.07), P=0.049] were the independent risk factors of all-cause mortality in maintenance dialysis patients. Stepwise Cox regression analysis showed that IATI<0.42 was still an independent protective factor of all-cause mortality in maintenance dialysis patients [<0.42/≥0.42, HR (95% CI): 0.45 (0.27-0.76), P=0.003]. Multivariate logistic regression analysis showed that low skeletal muscle density [ OR (95% CI): 0.84 (0.81-0.88), P<0.001] and high serum triglyceride [ OR (95% CI): 1.39 (1.07-1.82), P=0.015] were the independent influencing factors of IATI≥0.42. Conclusion:IATI<0.42 of the first lumbar level is an independent protective factor of all-cause mortality in maintenance dialysis patients. Localized myosteatosis within high-quality skeletal muscle may reduce the risk of all-cause mortality in these patients.