Objective:To explore the relationship between sperm DNA integrity, semen parameters, seminal plasma neutral α-glucosidase activity and in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes. Methods:The clinical data of 300 male infertile patients who underwent routine semen analysis in the Second Affiliated Hospital of Air Force Medical University from October 2023 to April 2024 and whose spouses received IVF/ICSI treatment were retrospectively analyzed. The results of sperm DNA integrity [sperm DNA fragmentation index (DFI)], semen parameters (sperm percentage, sperm density, sperm motility, normal morphology sperm rate) and seminal plasma neutral α-glucosidase activity at admission were recorded. According to their spouses′ IVF/ICSI outcomes, the 300 patients were divided into the successful pregnancy group (those with successful intrauterine pregnancy detected by ultrasound 30 days after transplantation) and the unsuccessful pregnancy group (those without successful intrauterine pregnancy detected by ultrasound 30 days after transplantation). The differences in sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity at admission between the two groups were compared. The receiver operating characteristic (ROC) curve was used to analyze the predictive efficacy of sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity in male infertile patients at admission for their spouses′ IVF/ICSI outcomes.Results:According to the IVF/ICSI outcomes of the spouses of male infertile patients, 169 cases (56.3%) had successful intrauterine pregnancy detected by ultrasound 30 days after transplantation; 131 cases (43.7%) had unsuccessful intrauterine pregnancy. At admission, there was no statistically significant difference in clinical data between the two groups (all P>0.05). The DFI and sperm density in the successful pregnancy group were lower than those in the unsuccessful pregnancy group, while the sperm percentage, sperm motility, normal morphology sperm rate and seminal plasma neutral α-glucosidase activity were higher than those in the unsuccessful pregnancy group (all P<0.05). The area under the ROC curve (AUC) values of single indicators including DFI, sperm percentage, sperm density, sperm motility, normal morphology sperm rate, and seminal plasma neutral α-glucosidase level in predicting the IVF/ICSI outcomes of spouses of male infertile patients were 0.719, 0.718, 0.812, 0.779, 0.769, and 0.736, respectively; the sensitivities were 70.42%, 77.46%, 69.01%, 70.42%, 69.01%, and 77.46%, respectively; the specificities were 66.38%, 55.02%, 81.22%, 73.80%, 77.29%, and 62.88%, respectively; the Youden indexes were 0.368, 0.325, 0.502, 0.442, 0.463, and 0.404, respectively; all differences were statistically significant (all P<0.05). Conclusions:Sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity can assist in predicting IVF/ICSI outcomes, providing an important reference for the treatment outcomes of male infertile patients.

Objective:To investigate the characteristic distribution of vaginal microbiota in infertile women.Methods:We collected the results of vaginal microbiological examinations from 19322 initial visit infertile women who visited the Reproductive Medicine Center of the Department of Obstetrics and Gynecology,the Second Affili-ated Hospital of Air Force Medical University from March 1,2023 to July 31,2024.The vaginal microbiota infection status of patients was compared in different age groups(＜25 years old,25-＜30 years old,30-＜35 years old,35-＜40 years old,≥40 years old)and different seasons(spring,summer,autumn,winter).Results:①Among 19322 women,6027 cases(31.19％)showed abnormal vaginal microecology.Pathogenic microorganisms were detected in 3093 cases,including 2882 cases of single vaginitis,211 cases of mixed vaginitis,3764 cases with vagi-nal cleanliness grade Ⅲ-Ⅳ,and 3965 cases with abnormal lactobacilli.Among patients with single vaginitis,1349 cases(46.81％)were diagnosed with vulvovaginal candidiasis(VVC),which was the highest proportion.Aerobic vaginitis(AV)followed with 752 cases(26.09％),and bacterial vaginosis(BV)had 671 cases(23.28％),trichomonal vaginitis(TV)with 110 cases(3.82％).Among patients with mixed vaginitis,AV+BV was the most common with 96 cases(45.49％).②The detection rates of cleanliness grade Ⅲ-Ⅳ,abnormal lactobacilli,abnor-mal microorganisms(unclear pathogen),single vaginitis(BV,VVC and TV),and mixed vaginitis showed statisti-cally significant differences across different seasons(P＜0.05).Specifically,the detection rates of cleanliness grade Ⅲ-Ⅳ and abnormal microorganisms(unclear pathogens)were significantly higher in autumn than in other seasons(P＜0.05),while the detection rate of abnormal lactobacilli was higher in spring than in other seasons(P＜0.05).③The detection rates of abnormal lactobacilli,abnormal microorganisms(unclear pathogen),single vaginitis(BV,VVC and AV),and mixed vaginitis showed significant differences among different age groups(P＜0.05).Specifically,the detection rate of abnormal microorganisms(unclear pathogen)was higher in the age group＜25 years than in other age groups(P＜0.05),while the detection rate of BV among single vaginitis cases was higher in the age group≥40 years than in other age groups(P＜0.05).Conclusions:The vaginal microecol-ogy of infertile women varies in terms of infection rates across different age groups and seasons.Patients with simple vaginitis have the highest rate of VVC,while those with mixed vaginitis have the highest proportion of AV+BV infection.

Objective:To explore the relationship between sperm DNA integrity, semen parameters, seminal plasma neutral α-glucosidase activity and in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes. Methods:The clinical data of 300 male infertile patients who underwent routine semen analysis in the Second Affiliated Hospital of Air Force Medical University from October 2023 to April 2024 and whose spouses received IVF/ICSI treatment were retrospectively analyzed. The results of sperm DNA integrity [sperm DNA fragmentation index (DFI)], semen parameters (sperm percentage, sperm density, sperm motility, normal morphology sperm rate) and seminal plasma neutral α-glucosidase activity at admission were recorded. According to their spouses′ IVF/ICSI outcomes, the 300 patients were divided into the successful pregnancy group (those with successful intrauterine pregnancy detected by ultrasound 30 days after transplantation) and the unsuccessful pregnancy group (those without successful intrauterine pregnancy detected by ultrasound 30 days after transplantation). The differences in sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity at admission between the two groups were compared. The receiver operating characteristic (ROC) curve was used to analyze the predictive efficacy of sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity in male infertile patients at admission for their spouses′ IVF/ICSI outcomes.Results:According to the IVF/ICSI outcomes of the spouses of male infertile patients, 169 cases (56.3%) had successful intrauterine pregnancy detected by ultrasound 30 days after transplantation; 131 cases (43.7%) had unsuccessful intrauterine pregnancy. At admission, there was no statistically significant difference in clinical data between the two groups (all P>0.05). The DFI and sperm density in the successful pregnancy group were lower than those in the unsuccessful pregnancy group, while the sperm percentage, sperm motility, normal morphology sperm rate and seminal plasma neutral α-glucosidase activity were higher than those in the unsuccessful pregnancy group (all P<0.05). The area under the ROC curve (AUC) values of single indicators including DFI, sperm percentage, sperm density, sperm motility, normal morphology sperm rate, and seminal plasma neutral α-glucosidase level in predicting the IVF/ICSI outcomes of spouses of male infertile patients were 0.719, 0.718, 0.812, 0.779, 0.769, and 0.736, respectively; the sensitivities were 70.42%, 77.46%, 69.01%, 70.42%, 69.01%, and 77.46%, respectively; the specificities were 66.38%, 55.02%, 81.22%, 73.80%, 77.29%, and 62.88%, respectively; the Youden indexes were 0.368, 0.325, 0.502, 0.442, 0.463, and 0.404, respectively; all differences were statistically significant (all P<0.05). Conclusions:Sperm DNA integrity, semen parameters and seminal plasma neutral α-glucosidase activity can assist in predicting IVF/ICSI outcomes, providing an important reference for the treatment outcomes of male infertile patients.

Objective:To investigate the completion rate of tumor evaluation at initial assessment and after neoadjuvant therapy for mid and low rectal cancer patients in the national multicenter real-world database.Methods:The prospective real-world study was conducted. The clinicopathological data of 1 074 patients who underwent surgical treatment for mid and low rectal cancer in 47 national medical institutions, including Peking Union Medical College Hospital et al, from May 12,2023 to May 11,2024 were collected. Observation indicators: (1) clinical characteristics of patients with mid and low rectal cancer; (2) initial colonoscopy and pathologic evaluation of tumors in patients with mid and low rectal cancer; (3) initial imaging evaluation of patients with mid and low rectal cancer; (4) imaging evaluation after neoadjuvant therapy for patients with mid and low rectal cancer. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distribution were represented as M( Q1, Q3). Count data were described as absoluter numbers and/or percentages. Results:(1) Clinical characteristics of patients with mid and low rectal cancer. Of the 1 074 patients, there were 713 males and 361 females, aged 63(56,70)years. The body mass index of 1 074 patients was 24(21,26)kg/m 2.For American Society of Anesthesiologists classification, there were 147 cases of stage Ⅰ, 641 cases of stage Ⅱ, 157 cases of stage Ⅲ, 2 cases of stage Ⅳ, and there were 127 cases missing data. (2) Initial colonoscopy and pathologic evaluation of tumors in patients with mid and low rectal cancer. Of the 1 074 patients, there were 787 cases (73.28%) undergoing complete colonoscopy, and there were only 197 cases (18.34%) undergoing immunohistochemical evaluation of all four mismatch repair proteins. (3) Initial imaging evaluation of patients with mid and low rectal cancer. Of the 1 074 patients, there were 842(78.40%) patients completing magnetic resonance imaging (MRI) or ultrasound evaluation, and there were 914(85.10%) patients completing chest, abdomen, and pelvis enhanced computed tomography (CT) evaluation. In the 149 patients completing rectal ultrasound evaluation, there were 122 cases (81.88%) comple-ting T staging evaluation, and there were 81 cases (54.36%) completing N staging evaluation. In the 808 patients completing rectal MRI evaluation, there were 708 cases (87.62%) completing T staging evaluation, and there were 590 cases (73.02%) completing N staging evaluation. (4) Imaging evalua-tion after neoadjuvant therapy for patients with mid and low rectal cancer. Of the 388 patients with neoadjuvant therapy, there were 332 patients (85.57%) completing MRI or ultrasound evaluation, and there were 327 patients (84.28%) completing chest, abdomen, and pelvis enhanced CT evalua-tion. In the 70 patients completing rectal ultrasound evaluation, there were 65 cases (92.86%) com-pleting T staging evaluation, and there were 49 cases (70.00%) completing N staging evaluation. In the 327 patients completing rectal MRI evaluation, there were 246 cases (75.23%) completing T staging, and there were 228 cases (69.72%) completing N staging evaluation. Conclusion:The com-pletion rate of tumor imaging evaluation at initial assessment and after neoadjuvant therapy for mid and low rectal cancer patients on a national scale is relatively good.

Objective:To investigate the completion rate of tumor evaluation at initial assessment and after neoadjuvant therapy for mid and low rectal cancer patients in the national multicenter real-world database.Methods:The prospective real-world study was conducted. The clinicopathological data of 1 074 patients who underwent surgical treatment for mid and low rectal cancer in 47 national medical institutions, including Peking Union Medical College Hospital et al, from May 12,2023 to May 11,2024 were collected. Observation indicators: (1) clinical characteristics of patients with mid and low rectal cancer; (2) initial colonoscopy and pathologic evaluation of tumors in patients with mid and low rectal cancer; (3) initial imaging evaluation of patients with mid and low rectal cancer; (4) imaging evaluation after neoadjuvant therapy for patients with mid and low rectal cancer. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distribution were represented as M( Q1, Q3). Count data were described as absoluter numbers and/or percentages. Results:(1) Clinical characteristics of patients with mid and low rectal cancer. Of the 1 074 patients, there were 713 males and 361 females, aged 63(56,70)years. The body mass index of 1 074 patients was 24(21,26)kg/m 2.For American Society of Anesthesiologists classification, there were 147 cases of stage Ⅰ, 641 cases of stage Ⅱ, 157 cases of stage Ⅲ, 2 cases of stage Ⅳ, and there were 127 cases missing data. (2) Initial colonoscopy and pathologic evaluation of tumors in patients with mid and low rectal cancer. Of the 1 074 patients, there were 787 cases (73.28%) undergoing complete colonoscopy, and there were only 197 cases (18.34%) undergoing immunohistochemical evaluation of all four mismatch repair proteins. (3) Initial imaging evaluation of patients with mid and low rectal cancer. Of the 1 074 patients, there were 842(78.40%) patients completing magnetic resonance imaging (MRI) or ultrasound evaluation, and there were 914(85.10%) patients completing chest, abdomen, and pelvis enhanced computed tomography (CT) evaluation. In the 149 patients completing rectal ultrasound evaluation, there were 122 cases (81.88%) comple-ting T staging evaluation, and there were 81 cases (54.36%) completing N staging evaluation. In the 808 patients completing rectal MRI evaluation, there were 708 cases (87.62%) completing T staging evaluation, and there were 590 cases (73.02%) completing N staging evaluation. (4) Imaging evalua-tion after neoadjuvant therapy for patients with mid and low rectal cancer. Of the 388 patients with neoadjuvant therapy, there were 332 patients (85.57%) completing MRI or ultrasound evaluation, and there were 327 patients (84.28%) completing chest, abdomen, and pelvis enhanced CT evalua-tion. In the 70 patients completing rectal ultrasound evaluation, there were 65 cases (92.86%) com-pleting T staging evaluation, and there were 49 cases (70.00%) completing N staging evaluation. In the 327 patients completing rectal MRI evaluation, there were 246 cases (75.23%) completing T staging, and there were 228 cases (69.72%) completing N staging evaluation. Conclusion:The com-pletion rate of tumor imaging evaluation at initial assessment and after neoadjuvant therapy for mid and low rectal cancer patients on a national scale is relatively good.

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 characteristic distribution of vaginal microbiota in infertile women.Methods:We collected the results of vaginal microbiological examinations from 19322 initial visit infertile women who visited the Reproductive Medicine Center of the Department of Obstetrics and Gynecology,the Second Affili-ated Hospital of Air Force Medical University from March 1,2023 to July 31,2024.The vaginal microbiota infection status of patients was compared in different age groups(＜25 years old,25-＜30 years old,30-＜35 years old,35-＜40 years old,≥40 years old)and different seasons(spring,summer,autumn,winter).Results:①Among 19322 women,6027 cases(31.19％)showed abnormal vaginal microecology.Pathogenic microorganisms were detected in 3093 cases,including 2882 cases of single vaginitis,211 cases of mixed vaginitis,3764 cases with vagi-nal cleanliness grade Ⅲ-Ⅳ,and 3965 cases with abnormal lactobacilli.Among patients with single vaginitis,1349 cases(46.81％)were diagnosed with vulvovaginal candidiasis(VVC),which was the highest proportion.Aerobic vaginitis(AV)followed with 752 cases(26.09％),and bacterial vaginosis(BV)had 671 cases(23.28％),trichomonal vaginitis(TV)with 110 cases(3.82％).Among patients with mixed vaginitis,AV+BV was the most common with 96 cases(45.49％).②The detection rates of cleanliness grade Ⅲ-Ⅳ,abnormal lactobacilli,abnor-mal microorganisms(unclear pathogen),single vaginitis(BV,VVC and TV),and mixed vaginitis showed statisti-cally significant differences across different seasons(P＜0.05).Specifically,the detection rates of cleanliness grade Ⅲ-Ⅳ and abnormal microorganisms(unclear pathogens)were significantly higher in autumn than in other seasons(P＜0.05),while the detection rate of abnormal lactobacilli was higher in spring than in other seasons(P＜0.05).③The detection rates of abnormal lactobacilli,abnormal microorganisms(unclear pathogen),single vaginitis(BV,VVC and AV),and mixed vaginitis showed significant differences among different age groups(P＜0.05).Specifically,the detection rate of abnormal microorganisms(unclear pathogen)was higher in the age group＜25 years than in other age groups(P＜0.05),while the detection rate of BV among single vaginitis cases was higher in the age group≥40 years than in other age groups(P＜0.05).Conclusions:The vaginal microecol-ogy of infertile women varies in terms of infection rates across different age groups and seasons.Patients with simple vaginitis have the highest rate of VVC,while those with mixed vaginitis have the highest proportion of AV+BV infection.

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.