Objective:To research the mechanism of the regulation of homeobox B8(HOXB8)for lysine demethylase 6B(KDM6B)-mediated CCAAT/enhancer binding protein α(C/EBPα)axis on the metastasis of high-grade serous ovarian cancer(HGSOC),so as to provide references for the study of the pathogenesis of HGSOC patients.Methods:The tumor tissue samples and corresponding adjacent normal tissue samples of HGSOC patients admitted to Wuhan Hospital of Traditional Chinese and Western Medicine from June to December 2024 were selected,and cell lines SKOV3 and A2780 of ovarian cancer were collected.Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)was adopted to detect the mRNA levels of KDM6B in HGSOC tumor tissues and its corresponding adjacent tissues.Western blot assay and immunohistochemistry were adopted to detect the expressions of KDM6B protein in the tissue.The A2780 cells of ovarian cancer were divided into the oe-HOXB8 group that was transfected by the HOXB8 overexpression vector,and the oe-NCHOXB8 group with the negative control(NC)vector.The SKOV3 cells of ovarian cancer were divided into the si-HOXB8 group that was transfected by the HOXB8 small interference sequence,and the si-NCHOXB8 group with negative control sequence.The transfected KDM6B was divided into the si-KDM6B group with small interference sequence and the oe-KDM6B group transfected with overexpression vector.The co-transfection HOXB8 and(or)KDM6B,C/EBPα were divided into si-HOXB8+si-KDM6B group and si-HOXB8+si-C/EBPα group of small interference sequence.The chromatin immunoprecipitation-qPCR(ChIP-qPCR)and dual-luciferase reporter gene assay were used to verify the mechanism that HOXB8 transcript and regulate KDM6B in SKOV3 and A2780 cells of ovarian cancer.The effects of overexpression or silencing of HOXB8 in A2780 and SKOV3 cells on the proliferation,invasion,migration and KDM6B expression of ovarian cancer cells were detected.The effects of overexpression or silencing of KDM6B in SKOV3 cells on the trimethylation modification of lysine 27 at histone H3(H3K27me3)and the expression of C/EBPα were detected.The effects of silencing KDM6B and C/EBPα on HOXB8-induced cell proliferation,invasion and migration were analyzed through functional rescue experiments.Results:In tumor tissues,the mRNA and protein expression levels of KDM6B were 1.02±0.03 and 1.02±0.04,respectively,which were significantly higher than those in the adjacent tissues,and the differences were statistically significant(t=62.440,38.737,P<0.01).The optical density value of proliferation,invasion rate and migration rate of A2780 cells in the oe-HOXB8 group that was transfected by the HOXB8 overexpression vector were respectively(1.74±0.15),(89.71±6.60)%and(85.33%±7.02)%,which were significantly higher than those in the oe-NCHOXB8 group,and the differences were statistically significant(t=7.778,7.353,4.759,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8 group were respectively(0.54±0.06),(47.23±3.41)%and(43.20±3.12)%,all of which were significantly lower than those in the si-NCHOXB8 group,and the differences were statistically significant(t=9.400,8.615,9.040,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8+si-KDM6B group were(1.04±0.09),(73.11±4.98)%and(68.65±4.45)%,respectively,which were significantly higher than those in the si-HOXB8 group,and the differences were all statistically significant(t=6.875,6.852,7.562,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8+si-C/EBPα group were respectively(0.97±0.07),(75.87±5.12)%and(70.59±4.81)%,all of which were significantly higher than those in the si-HOXB8 group,and the differences were all statistically significant(t=6.355,7.500,7.884,P<0.01).Conclusion:HOXB8 can inhibit the C/EBPα expression and promote the HGSOC metastasis by regulating and controlling H3K27me3 modification of KDM6B-mediated C/EBPα histone.

ObjectiveThis study aims to investigate the effect of Dictamni Cortex on intestinal barrier damage in rats and its mechanism by untargeted metabolomics and targeted metabolomics for short-chain fatty acids （SCFAs）. MethodsRats were randomly divided into a control group， a high-dose group of Dictamni Cortex （8.1 g·kg^-1）， a medium-dose group （2.7 g·kg^-1）， and a low-dose group （0.9 g·kg^-1）. Except for the control group， the other groups were administered different doses of Dictamni Cortex by gavage for eight consecutive weeks. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in the ileal tissue. Enzyme-linked immunosorbent assay （ELISA） was employed to detect the level of cytokines， including tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， and interleukin-1β （IL-1β）， in the ileal tissue of rats. Quantitative real-time fluorescence polymerase chain reaction （Real-time PCR） technology was used to detect the expression level of tight junction proteins， including zonula occludens-1 （ZO-1）， Occludin， and Claudin-1 mRNAs， in the ileal tissue of rats to preliminarily explore the effects of Dictamni Cortex on intestinal damage. The dose with the most significant toxic phenotype was selected to further reveal the effects of Dictamni Cortex on the metabolic profile of ileal tissue in rats by non-targeted metabolomics combined with targeted metabolomics for SCFAs. ResultsCompared with the control group， all doses of Dictamni Cortex induced varying degrees of pathological damage in the ileum， increased TNF-α （P<0.01）， IL-6 （P<0.01）， and IL-1β （P<0.01） levels in the ileal tissue， and decreased the expression level of ZO-1 （P<0.05， P<0.01）， Occludin （P<0.01）， and Claudin-1 （P<0.05） in the ileal tissue， with the high-dose group showing the most significant toxic phenotypes. The damage mechanisms of the high-dose group of Dictamni Cortex on the ileal tissue were further explored by integrating non-targeted metabolomics and targeted metabolomics for SCFAs. The non-targeted metabolomics results showed that 21 differential metabolites were identified in the control group and the high-dose group. Compared with that in the control group， after Dictamni Cortex intervention， the level of 14 metabolites was significantly increased （P<0.05， P<0.01）， and the level of seven metabolites was significantly decreased （P<0.05， P<0.01） in the ileal contents. These metabolites collectively acted on 10 related metabolic pathways， including glycerophospholipids and primary bile acid biosynthesis. The quantitative data of targeted metabolomics for SCFAs showed that Dictamni Cortex intervention disrupted the level of propionic acid， butyric acid， acetic acid， caproic acid， isobutyric acid， isovaleric acid， valeric acid， and isocaproic acid in the ileal contents of rats. Compared with those in the control group， the level of isobutyric acid， isovaleric acid， and valeric acid were significantly increased， while the level of propionic acid， butyric acid， and acetic acid were significantly decreased in the ileal contents of rats after Dictamni Cortex intervention （P<0.05， P<0.01）. ConclusionDictamni Cortex can induce intestinal damage by regulating glycerophospholipid metabolism， primary bile acid biosynthesis， and metabolic pathways for SCFAs.

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 research the mechanism of the regulation of homeobox B8(HOXB8)for lysine demethylase 6B(KDM6B)-mediated CCAAT/enhancer binding protein α(C/EBPα)axis on the metastasis of high-grade serous ovarian cancer(HGSOC),so as to provide references for the study of the pathogenesis of HGSOC patients.Methods:The tumor tissue samples and corresponding adjacent normal tissue samples of HGSOC patients admitted to Wuhan Hospital of Traditional Chinese and Western Medicine from June to December 2024 were selected,and cell lines SKOV3 and A2780 of ovarian cancer were collected.Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)was adopted to detect the mRNA levels of KDM6B in HGSOC tumor tissues and its corresponding adjacent tissues.Western blot assay and immunohistochemistry were adopted to detect the expressions of KDM6B protein in the tissue.The A2780 cells of ovarian cancer were divided into the oe-HOXB8 group that was transfected by the HOXB8 overexpression vector,and the oe-NCHOXB8 group with the negative control(NC)vector.The SKOV3 cells of ovarian cancer were divided into the si-HOXB8 group that was transfected by the HOXB8 small interference sequence,and the si-NCHOXB8 group with negative control sequence.The transfected KDM6B was divided into the si-KDM6B group with small interference sequence and the oe-KDM6B group transfected with overexpression vector.The co-transfection HOXB8 and(or)KDM6B,C/EBPα were divided into si-HOXB8+si-KDM6B group and si-HOXB8+si-C/EBPα group of small interference sequence.The chromatin immunoprecipitation-qPCR(ChIP-qPCR)and dual-luciferase reporter gene assay were used to verify the mechanism that HOXB8 transcript and regulate KDM6B in SKOV3 and A2780 cells of ovarian cancer.The effects of overexpression or silencing of HOXB8 in A2780 and SKOV3 cells on the proliferation,invasion,migration and KDM6B expression of ovarian cancer cells were detected.The effects of overexpression or silencing of KDM6B in SKOV3 cells on the trimethylation modification of lysine 27 at histone H3(H3K27me3)and the expression of C/EBPα were detected.The effects of silencing KDM6B and C/EBPα on HOXB8-induced cell proliferation,invasion and migration were analyzed through functional rescue experiments.Results:In tumor tissues,the mRNA and protein expression levels of KDM6B were 1.02±0.03 and 1.02±0.04,respectively,which were significantly higher than those in the adjacent tissues,and the differences were statistically significant(t=62.440,38.737,P<0.01).The optical density value of proliferation,invasion rate and migration rate of A2780 cells in the oe-HOXB8 group that was transfected by the HOXB8 overexpression vector were respectively(1.74±0.15),(89.71±6.60)%and(85.33%±7.02)%,which were significantly higher than those in the oe-NCHOXB8 group,and the differences were statistically significant(t=7.778,7.353,4.759,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8 group were respectively(0.54±0.06),(47.23±3.41)%and(43.20±3.12)%,all of which were significantly lower than those in the si-NCHOXB8 group,and the differences were statistically significant(t=9.400,8.615,9.040,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8+si-KDM6B group were(1.04±0.09),(73.11±4.98)%and(68.65±4.45)%,respectively,which were significantly higher than those in the si-HOXB8 group,and the differences were all statistically significant(t=6.875,6.852,7.562,P<0.01).The optical density value of proliferation,invasion rate and migration rate of SKOV3 cells in the si-HOXB8+si-C/EBPα group were respectively(0.97±0.07),(75.87±5.12)%and(70.59±4.81)%,all of which were significantly higher than those in the si-HOXB8 group,and the differences were all statistically significant(t=6.355,7.500,7.884,P<0.01).Conclusion:HOXB8 can inhibit the C/EBPα expression and promote the HGSOC metastasis by regulating and controlling H3K27me3 modification of KDM6B-mediated C/EBPα histone.

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:To explore the risk factors and outcomes of central nervous system(CNS)complications associated with hematopoietic stem cell transplantation(HSCT).Methods:A total of 550 recipient after HSCT in the department of hematology of Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology from January 1 2019 to August 31 2021were enrolled.According to the occurrence of CNS complications, they were divided into the CNS group(24 cases)and the non CNS group(526 cases). The clinical information and prognosis were compared.We further analyzed the risk factors associated with CNS complications, and conducted multivariate logistic regression on statistically significant indicators.Cox regression analysis is conducted on prognostic factors such as age, gender and risk degree.Results:A total of 550 recipients were enrolled, of which 330 underwent allo-HSCT, and others received auto-HSCT.A total of 24 cases (4.36%)had CNS complications, of which 4 cases had 2 types of CNS complications.The type of CNS complications included intracranial infection(8 cases, 28.57%), transplantation-associated thrombotic microangiopathy(TA-TMA)(6 cases, 21.43%), central tumor invasion(4 cases, 14.29%), intracranial hemorrhage(4 cases, 14.29%), leucodystrophy(2 cases, 7.14%)and unexplained encephalopathy(4 cases, 14.29%). Logistic regression analysis of risk factors related to CNS complications showed that, Platelet implantation time( β=0.084, OR=1.088, P=0.048), CMV infection( β=1.295, OR=3.65, P=0.008)is positively correlated with the occurrence of CNS complications in HSCT recipients but age( β=-0.052, OR=0.949, P=0.004)is negatively correlated with it.Nine of the 24 cases(37.50%)who experienced CNS complications died, including 3 cases of intracranial infection, 3 cases of cerebral hemorrhage, 2 cases of TMA, and 1 case of unexplained encephalopathy.Platelet implantation time is an independent risk factor for poor prognosis of CNS complications in HSCT recipients. Conclusions:Our results indicated that, age, CMV infection and platelet implantation time were associated with the occurrence of CNS complications after HSCT.Platelet implantation time is an independent risk factor for poor prognosis of CNS complications in HSCT recipients.