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.

BACKGROUND:Previous studies have found that for postmenopausal osteoporosis patients,the Bushen Jianpi Formula can help regulate serum osteoclast-and osteoblast-related factors and intestinal flora levels,improve clinical symptoms of patients and further improve efficacy.OBJECTIVE:To investigate the effect of Bushen Jianpi Formula on bone metabolism and bone microarchitecture in ovariectomized rats.METHODS:Twenty-four female SD rats were randomly divided into four groups by random number table method:sham operation group(n=6)was subjected to periovarian fat removal,and bilateral ovariectomy was performed in model group(n=6),alendronate group(n=6),and Bushen Jianpi Formula group(n=6).Five days after modeling,the Bushen Jianpi Formula group was given Bushen Jianpi Formula by intragastric administration(once a day).The alendronate sodium group was given alendronate by intragastric administration(once a week).The sham operation group and model group were given an equal volume of normal saline by intragastric administration(once a day)for 12 consecutive weeks.After intragastric administration,serum levels of procollagen Ⅰ N-terminal peptide,β-isomerized C-terminal telopeptide of type Ⅰ collagen degradation product,and tumor necrosis factor α were detected.The distal femur microstructure was detected by Micro-CT.The femoral tissue morphology was observed by hematoxylin-eosin staining.The expression of type Ⅰ collagen and tumor necrosis factorα in the femur was detected by immunohistochemical staining.RESULTS AND CONCLUSION:(1)The serum ELISA test showed that compared with the sham operation group,the level of procollagen Ⅰ N-terminal peptide in the model group decreased(P＜0.05),and the levels of degradation products of β-isomerized C-terminal telopeptide of type Ⅰ collagen and tumor necrosis factor α increased(P＜0.05).Compared with the model group,the levels of the procollagen Ⅰ N-terminal peptide in the Bushen Jianpi Formula group and the alendronate sodium group increased(P＜0.05),and the levels of β-isomerized C-terminal telopeptide of type Ⅰ collagen degradation products and tumor necrosis factor α decreased(P＜0.05).(2)Micro-CT three-dimensional reconstruction showed that compared with the sham operation group,the number of bone trabeculae in the model group was significantly reduced,the continuity was worsened,and the gaps were increased.Both alendronate sodium and Bushen Jianpi Formula had a positive improvement effect on this phenomenon.(3)Hematoxylin-eosin staining showed that compared with the sham operation group,the number of bone trabeculae in the model group was reduced and the shape became thinner,and the network structure was destroyed.Compared with the model group,the number of bone trabeculae in the Bushen Jianpi Formula group and the alendronate sodium group increased,the shape became thicker,and the reticular structure was restored.(4)Immunohistochemical staining showed that compared with the sham operation group,the expression of type Ⅰ collagen was reduced and tumor necrosis factor α expression was increased in the model group.Compared with the model group,the expression of type Ⅰ collagen increased and the expression of tumor necrosis factor α decreased in the Bushen Jianpi Formula group and the alendronate sodium group.The results show that the Bushen Jianpi Formula can effectively improve bone metabolism and bone microstructure in ovariectomized rats.

Objective To investigate the presumed correlation between lactate level and clearance during extracorporeal life support(ECLS)and death in elderly cardiac intensive care patients.Methods A total of 93 elderly cardiac intensive care patients who received ECLS in Department of Critical Care Medicine,Xiangya Medical College Affiliated Changsha Hospital,Central South University,from March 2019 to October 2024 were retrospectively included to manage low cardiac production syndrome after major cardiac surgery.According to hospital outcomes,the patients were divided into a death group(n=45)and a survival group(n=48).Blood lactate measurements were performed every 4 hours from the beginning of ECLS treatment to calculate peak lactate and lactate clearance rate(LCR).Routine ICU scores,such as sequential organ failure score(SOFA)and reactive organ dysfunction(ROD)score,and postoperative complications were recorded.Results The death group received larger amounts of packed red blood cell concentrate,fresh frozen plasma and platelet concentrate,and exhibited higher ratios of norepinephrine and epinephrine administration and higher incidences of re-thoracotomy and hemolytic episodes when compared with the survival group(P＜0.05,P＜0.01).At the end of ECLS,higher SOFA and ROD scores were observed in the death group(P＜0.01).The death group also demonstrated higher lactate level from venoarterial ECLS(P＜0.001)and increased median peak lactate level,but lower median LCR than the survival group(P＜0.01).Multivariate logistic analysis showed that peak lactate and LCR were independent prognostic factors in the elderly cardiac ICU patients(P＜0.05,P＜0.01).The AUC value(95％CI)of peak lactate and LCR in predicting patient outcomes was 0.723(95％CI:0.615-0.831)and 0.846(95％CI:0.761-0.932),respectively,and the value of their combination in predicting in-hospital death was 0.846(95％CI:0.762-0.931),with a sensitivity of 0.629 and a specificity of 0.937.Conclusion Lactate level and its clearance rate during ECLS can affect the survival rate of elderly cardiac intensive care patients.Peak lactate and LCR can predict the prognosis of elderly cardiac intensive care patients,and can be used as prognostic indicators for clinical monitoring.

BACKGROUND:Previous studies have found that for postmenopausal osteoporosis patients,the Bushen Jianpi Formula can help regulate serum osteoclast-and osteoblast-related factors and intestinal flora levels,improve clinical symptoms of patients and further improve efficacy.OBJECTIVE:To investigate the effect of Bushen Jianpi Formula on bone metabolism and bone microarchitecture in ovariectomized rats.METHODS:Twenty-four female SD rats were randomly divided into four groups by random number table method:sham operation group(n=6)was subjected to periovarian fat removal,and bilateral ovariectomy was performed in model group(n=6),alendronate group(n=6),and Bushen Jianpi Formula group(n=6).Five days after modeling,the Bushen Jianpi Formula group was given Bushen Jianpi Formula by intragastric administration(once a day).The alendronate sodium group was given alendronate by intragastric administration(once a week).The sham operation group and model group were given an equal volume of normal saline by intragastric administration(once a day)for 12 consecutive weeks.After intragastric administration,serum levels of procollagen Ⅰ N-terminal peptide,β-isomerized C-terminal telopeptide of type Ⅰ collagen degradation product,and tumor necrosis factor α were detected.The distal femur microstructure was detected by Micro-CT.The femoral tissue morphology was observed by hematoxylin-eosin staining.The expression of type Ⅰ collagen and tumor necrosis factorα in the femur was detected by immunohistochemical staining.RESULTS AND CONCLUSION:(1)The serum ELISA test showed that compared with the sham operation group,the level of procollagen Ⅰ N-terminal peptide in the model group decreased(P＜0.05),and the levels of degradation products of β-isomerized C-terminal telopeptide of type Ⅰ collagen and tumor necrosis factor α increased(P＜0.05).Compared with the model group,the levels of the procollagen Ⅰ N-terminal peptide in the Bushen Jianpi Formula group and the alendronate sodium group increased(P＜0.05),and the levels of β-isomerized C-terminal telopeptide of type Ⅰ collagen degradation products and tumor necrosis factor α decreased(P＜0.05).(2)Micro-CT three-dimensional reconstruction showed that compared with the sham operation group,the number of bone trabeculae in the model group was significantly reduced,the continuity was worsened,and the gaps were increased.Both alendronate sodium and Bushen Jianpi Formula had a positive improvement effect on this phenomenon.(3)Hematoxylin-eosin staining showed that compared with the sham operation group,the number of bone trabeculae in the model group was reduced and the shape became thinner,and the network structure was destroyed.Compared with the model group,the number of bone trabeculae in the Bushen Jianpi Formula group and the alendronate sodium group increased,the shape became thicker,and the reticular structure was restored.(4)Immunohistochemical staining showed that compared with the sham operation group,the expression of type Ⅰ collagen was reduced and tumor necrosis factor α expression was increased in the model group.Compared with the model group,the expression of type Ⅰ collagen increased and the expression of tumor necrosis factor α decreased in the Bushen Jianpi Formula group and the alendronate sodium group.The results show that the Bushen Jianpi Formula can effectively improve bone metabolism and bone microstructure in ovariectomized rats.

Objective To investigate the presumed correlation between lactate level and clearance during extracorporeal life support(ECLS)and death in elderly cardiac intensive care patients.Methods A total of 93 elderly cardiac intensive care patients who received ECLS in Department of Critical Care Medicine,Xiangya Medical College Affiliated Changsha Hospital,Central South University,from March 2019 to October 2024 were retrospectively included to manage low cardiac production syndrome after major cardiac surgery.According to hospital outcomes,the patients were divided into a death group(n=45)and a survival group(n=48).Blood lactate measurements were performed every 4 hours from the beginning of ECLS treatment to calculate peak lactate and lactate clearance rate(LCR).Routine ICU scores,such as sequential organ failure score(SOFA)and reactive organ dysfunction(ROD)score,and postoperative complications were recorded.Results The death group received larger amounts of packed red blood cell concentrate,fresh frozen plasma and platelet concentrate,and exhibited higher ratios of norepinephrine and epinephrine administration and higher incidences of re-thoracotomy and hemolytic episodes when compared with the survival group(P＜0.05,P＜0.01).At the end of ECLS,higher SOFA and ROD scores were observed in the death group(P＜0.01).The death group also demonstrated higher lactate level from venoarterial ECLS(P＜0.001)and increased median peak lactate level,but lower median LCR than the survival group(P＜0.01).Multivariate logistic analysis showed that peak lactate and LCR were independent prognostic factors in the elderly cardiac ICU patients(P＜0.05,P＜0.01).The AUC value(95％CI)of peak lactate and LCR in predicting patient outcomes was 0.723(95％CI:0.615-0.831)and 0.846(95％CI:0.761-0.932),respectively,and the value of their combination in predicting in-hospital death was 0.846(95％CI:0.762-0.931),with a sensitivity of 0.629 and a specificity of 0.937.Conclusion Lactate level and its clearance rate during ECLS can affect the survival rate of elderly cardiac intensive care patients.Peak lactate and LCR can predict the prognosis of elderly cardiac intensive care patients,and can be used as prognostic indicators for clinical monitoring.

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.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology has the characteristics of high specificity and high throughput, making it rapidly applied and developed in the field of clinical testing. Its application in the monitoring of therapeutic drugs can effectively improve the quantitative accuracy and sensitivity, and formulate a personalized and optimal dosing plan for patients. However, this technology still faces some challenges, and automation, quality control, and quantitative traceability will be the future development direction.

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.