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 examine the clinical effect of endovascular treatment for patients with non-acute symptomatic anterior circulation distal medium artery disease (aDMAD).Methods:This is a retrospective case series study.Retrospective analysis was conducted on the clinical data of 28 patients(29 lesions) with non-acute symptomatic aDMAD who underwent endovascular treatment at the Department of Neurosurgery,Beijing Hospital from May 2018 to March 2024. There were 15 males and 13 females,with an age of (63.4±10.2) years (range:36 to 82 years). The course of disease were more than 72 hours of all the patients. Confirmed by digital subtraction angiography,the lesion was located in distal anterior circulation and (or) medium arteries. Among them, 21 lesions (72.4%) located at middle cerebral artery and 8 lesions (27.6%) located at anterior cerebral artery.The median degree of stenosis before surgery ( M(IQR)) was 90%(23%) (range:70% to 100%).After standardized drug treatment,there was still a transient ischemic attack or cerebral infarction in the vascular related area.The therapeutic effects and complications were analyzed,and the differences in the occurrence of target vessel restenosis under different interventional treatment methods were collected. Results:A total of 28 patients with 29 lesions underwent endovascular treatment, with a treatment success rate of 96.6% (28/29). The course of disease was 60(66)days (range:9 to 210 days). Simple plain balloon angioplasty was performed in 12 cases (13 lesions), drug-coated balloon (DCB) angioplasty in 7 cases (7 lesions), and stent placement in 9 cases (9 lesions). The median degree of stenosis after surgery was 20%(39%) (range:0 to 50%). There was no new cerebral infarctions,cerebral hemorrhages,or other complications during the perioperative period.Imaging follow-up was conducted on 23 lesions for 12(15)months(range:3 to 34 months),with 10 cases (43.5%) of restenosis,3 cases (13.0%) of symptomatic restenosis,and 4 cases (17.4%) of re-treatment. There were no new cases of cerebral hemorrhage or death during the follow-up process.The restenosis rate was 6/10 for the conventional balloon group,1/6 for the DCB group, and 3/7 for the stent group; the rate of symptomatic restenosis was 1/10 for the conventional balloon group,0/6 for the DCB group, and 2/7 for the stent group.Conclusions:Endovascular treatment for non-acute symptomatic aDMAD is relatively effective,but there is a high rate of restenosis postoperatively. DCB may reduce the occurrence of postoperative restenosis.

Objective:To investigated the relationship between magnetic resonance imaging(MRI)parameters and the molecular pathology of primary central nervous system lymphoma(PCNSL).Methods:We retrospectively analyzed 26 patients from The First Affiliated Hospital of Harbin Medical University between January 2020 and June 2023 classified into germinal center B-cell like(GCB)and non-germinal center B-cell like(non-GCB)groups based on cell origin,into Ki-67≥75%and<75%groups based on the Ki-67 index,into BCL-2+and BCL-2-groups based on BCL-2 expression,and into responsive and non-responsive groups based on their response to MAP+Bruton's tyrosine kinase inhib-itor(BTKi)treatment.We extracted and compared first-order parameters between the groups,including mean value,standard deviation,variance,coefficient of variation,skewness,kurtosis,and entropy from baseline MRI images.Results:Four parameters(variance,kurtosis,skewness,and coefficient of variation)showed no significant differences between groups.However,three parameters(mean,standard devi-ation,and entropy)significantly differed between the groups based on Ki-67 and BCL-2 expression.For the Ki-67 index,the three parameters'areas under the curve(AUC)were 0.731,0.831,and 0.913,respectively.For BCL-2 expression,the mean and standard deviation AUCs were 0.889 and 0.938,respectively.In addition,the mean and entropy parameters significantly differed between the groups categorized by cell origin and treatment responsiveness(P<0.05).Multi-parameter joint analysis demonstrated greater identification accuracy compared to util-izing individual quantitative parameters from texture analysis.Conclusions:The mean,standard deviation,and entropy MRI parameters can help predict Ki-67 and BCL-2 expression in patients with PCNSL and have evaluative functions for treatment.They are beneficial for preoper-ative non-invasive assessment of tumor malignancy,providing vidence for prognosis and treatment planning.

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 examine the clinical effect of endovascular treatment for patients with non-acute symptomatic anterior circulation distal medium artery disease (aDMAD).Methods:This is a retrospective case series study.Retrospective analysis was conducted on the clinical data of 28 patients(29 lesions) with non-acute symptomatic aDMAD who underwent endovascular treatment at the Department of Neurosurgery,Beijing Hospital from May 2018 to March 2024. There were 15 males and 13 females,with an age of (63.4±10.2) years (range:36 to 82 years). The course of disease were more than 72 hours of all the patients. Confirmed by digital subtraction angiography,the lesion was located in distal anterior circulation and (or) medium arteries. Among them, 21 lesions (72.4%) located at middle cerebral artery and 8 lesions (27.6%) located at anterior cerebral artery.The median degree of stenosis before surgery ( M(IQR)) was 90%(23%) (range:70% to 100%).After standardized drug treatment,there was still a transient ischemic attack or cerebral infarction in the vascular related area.The therapeutic effects and complications were analyzed,and the differences in the occurrence of target vessel restenosis under different interventional treatment methods were collected. Results:A total of 28 patients with 29 lesions underwent endovascular treatment, with a treatment success rate of 96.6% (28/29). The course of disease was 60(66)days (range:9 to 210 days). Simple plain balloon angioplasty was performed in 12 cases (13 lesions), drug-coated balloon (DCB) angioplasty in 7 cases (7 lesions), and stent placement in 9 cases (9 lesions). The median degree of stenosis after surgery was 20%(39%) (range:0 to 50%). There was no new cerebral infarctions,cerebral hemorrhages,or other complications during the perioperative period.Imaging follow-up was conducted on 23 lesions for 12(15)months(range:3 to 34 months),with 10 cases (43.5%) of restenosis,3 cases (13.0%) of symptomatic restenosis,and 4 cases (17.4%) of re-treatment. There were no new cases of cerebral hemorrhage or death during the follow-up process.The restenosis rate was 6/10 for the conventional balloon group,1/6 for the DCB group, and 3/7 for the stent group; the rate of symptomatic restenosis was 1/10 for the conventional balloon group,0/6 for the DCB group, and 2/7 for the stent group.Conclusions:Endovascular treatment for non-acute symptomatic aDMAD is relatively effective,but there is a high rate of restenosis postoperatively. DCB may reduce the occurrence of postoperative restenosis.

Objective: To observe the effects of multi sensory stimulation (MSS) intervention on the psychological state, neurobiology, and neuroelectrophysiological indicators of college students with Internet addiction disorder (IAD), so as to provide high quality evidence for the optimization of IAD intervention plans. Methods: At the beginning of the spring semester of 2022-2023 academic year, 114 first year and sophomore IAD college students from Chongqing Second Normal University were selected by group random sampling method, and were randomly assigned into control group, physical exercise group, and observation group (28 in each group). The control group received routine psychological intervention, while the physical exercise group received routine physical exercise on the basis of the control group. The observation group received a MSS intervention on the basis of the control group. The MSS intervention included 8 means of color, incense, music, lozenges, press needle, massage, Tai Chi and static work. The intervention periocl was from April 1 to June 30, 2023, and all three groups were intervened for 12 weeks. The revised Chinese Internet Addiction Scale (CIAS-R), Self Control Scale (SCS), Symptom Checklist-90 (SCL-90) were observed before and after intervention, dopamine (DA) and β Endorphin (β EP) concentration were collected, and the amplitude and latency levels of N200 were analyzed by Event Related Potential (ERP). Results: The CIAS-R score of the observation group (36.08±4.98) was lower than physical exercise group (49.55±5.19) and control group (54.82±4.10), and the SCS score of the observation group (76.08± 1.98 ) was higher than physical exercise group (66.16±1.92) and control group (52.59±1.53) ( F=12.08, 13.18, P <0.05). In comparison of various dimensions of SCL-90, the observation group showed lower scores in the four dimensions of somatization, depression, anxiety, and psychoticism compared to the other two groups ( F=9.11, 8.92, 8.17, 8.48, P <0.05). In the dimensions of obsessive-compulsive symptoms, interpersonal sensitivity, and others in observation group were lower than the control group ( F= 4.20 , 5.16, 5.60, P <0.05). However, there was no difference in the two dimensions of terror and paranoia among the three groups ( F=0.24, 0.19, P > 0.05). The levels in plasma DA, βEP and the amplitude and latency of N200 among observation group were better than other two groups, and the differences were statistically significant ( F=9.92, 8.93, 6.24, 8.05, P <0.05). Conclusion MSS intervention can alleviate the related symptoms of IAD college students, improve neurobiological and neurophysiological indicators.

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.