1.Research progress on second-generation protein arginine methyltransferase 5 inhibitors
Zheqi HU ; Chunxiang YIN ; Huihuan MAO ; Yiqing CHANG ; Qihua ZHU ; Yungen XU ; Guoqing GONG ; Yi ZOU
Journal of China Pharmaceutical University 2025;56(5):548-556
Protein arginine methyltransferase 5 (PRMT5) exhibits elevated expression levels in a variety of cancers and has emerged as a critical target for cancer therapy in recent years. However, first-generation PRMT5 inhibitors have exhibited inadequate selectivity, leading to significant hematological toxicity, thus limiting their clinical utility. The second-generation PRMT5 inhibitors have shown marked improvement in safety and efficacy by selectively targeting MTAP-null tumor cells without impacting normal cells. This review systematically summarizes the biological and functional roles of PRMT5 in MTAP-deficient tumor cells, and comprehensively analyzes the research and development process, molecular binding mechanisms, and the latest advancements in clinical trials of the five second-generation PRMT5 inhibitors currently under investigation, aiming to provide valuable insights for further in-depth studies in this field.
2.Investigation on status quo of indwelling needle use in 77 hospitals of Chongqing city
Jingwen QIN ; Liping LIU ; Luanjiao HU ; Yongxiang MAO ; Xu ZHANG ; Ying NIE ; Jie YANG ; Guangwei LIU
Chongqing Medicine 2025;54(2):500-504
Objective To investigate the status quo of indwelling needles use in the hospitals at all lev-els in Chongqing city,and to evaluate the normalization and safety of indwelling needles use by referring to Nursing Practice Standards for Intravenous Therapy.Methods A self-designed questionnaire was used in July 2023 to conduct a cross-sectional survey on the use of indwelling needles in the hospitals at all levels in Chongqing city.Results A total of 30 807 patients in 77 hospitals were included,among them 62.67%used indwelling needles.The closed type indwelling needles accounted for 88.87%and the safety type indwelling needles accounted for 41.74%.Non-needle infusion connectors accounted for 37.78%,and steel needle con-nected with heparin caps accounted for 51.69%.95.66%of puncture site was in the upper limb,the non-cor-rosive drug infusion accounted for 87.57%,and the complications occurrence rate was 2.46%.Among the 6 419 surveyed nurses,75.51%removed indwelling needles based on clinical indications.There were statistically significant differences in the usage rates of closed type indwelling needles and non-needle infusion connectors among hospitals at different levels(P<0.05).There were also statistically significant differences in the inci-dence rates of complication and phlebitis(P<0.05).Conclusion The overall application of indwelling needles in the hospitals at all levels in Chongqing city is generally standardized,but the use of safety type indwelling needles and needle-free infusion connectors still needs to be improved.
3.Effect of interleukin-8 regulation on monocyte chemotactic protein-1 secretion and expression through the NF-kappaB/p65 signaling pathway on the migration of residual epithelial cells in the lens capsule
Wei SI ; Su XU ; Yuhang ZHANG ; Yi MAO ; Keyu GUO ; Yanzhong HU ; Fengyan ZHANG
International Eye Science 2025;25(4):537-543
AIM: To investigate the effect of interleukin-8(IL-8)on the regulation of monocyte chemotactic protein-1(MCP-1)secreted by lens epithelial cells(LEC)during cell migration in the development of posterior capsule opacification(PCO).METHODS: A rat lens capsule model was established and cultured in medium supplemented with 10% fetal bovine serum. Upon migration of LEC to 30%-50% of the posterior capsule, serum was removed. The capsule was subsequently divided into two groups: a control group and an IL-8(15 ng/mL)treatment group. LEC migration was captured at multiple time points. The secretion and mRNA expression of MCP-1 were quantified using ELISA and RT-qPCR, respectively. Immunofluorescence was used to assess MCP-1 expression in the different experimental groups. SRA01/04 cells were divided into three groups: control, IL-8(15 ng/mL), and IL-8(15 ng/mL)+200 μmol/L Bindarit(BND)groups, with migration measured by the Transwell assay. Additionally, SRA01/04 cells were divided into negative control(NC), NC+15 ng/mL IL-8, and 15 ng/mL IL-8+p65 siRNA groups, and MCP-1 secretion and mRNA expression were further analyzed by ELISA and RT-qPCR.RESULTS:LEC migration in the rat lens capsule cultured in vitro showed that the cells migration of the 15 ng/mL IL-8 group significantly increased at 48, 72 and 96 h(all P<0.05). ELISA results revealed that MCP-1 levels in SRA01/04 cells from the 15 ng/mL IL-8-treated group were markedly higher than those in the control group at both 12 and 24 h(all P<0.05). RT-qPCR analysis also demonstrated a significant increase in MCP-1 mRNA expression in the 15 ng/mL IL-8 group at both time points(all P<0.05). Immunofluorescence staining indicated greater MCP-1 expression in capsular epithelial cells of the 15 ng/mL IL-8 group at 24 h(P=0.007). Transwell assays further confirmed increased cell migration in the 15 ng/mL IL-8 group compared to the control group(P=0.001), while the migration reduced in the 15 ng/mL IL-8+200 μmol/L BND group compared to the 15 ng/mL IL-8 group(P=0.003). Moreover, ELISA and RT-qPCR results demonstrated a significant increase in MCP-1 secretion and mRNA expression in the NC+15 ng/mL IL-8 group at both 12 and 24 h compared to the NC group(all P<0.01). In contrast, MCP-1 secretion and mRNA expression were reduced in the 15 ng/mL IL-8+p65 siRNA group compared to the NC+15 ng/mL IL-8 group at both time points(all P<0.01).CONCLUSION: IL-8 promotes the migration of residual epithelial cells and regulates the secretion and expression of MCP-1 in LEC. The mechanism underlying IL-8's effects appears to be mediated through the activation of the NF-κB/p65 signaling pathway.
4.DEB-BACE versus BACE for the treatment of advanced lung squamous cell carcinoma:a retrospective clinical study
Fenfen XU ; Linqiang LAI ; Dengke ZHANG ; Jie CHEN ; Daxia CAI ; Ruolan MAO ; Ruhai HU ; Yonghui WANG ; Jianfei TU
Journal of Interventional Radiology 2025;34(6):597-602
Objective To investigate the effectiveness and safety of drug-eluting beads bronchial arterial chemoembolization(DEB-BACE)versus BACE for the treatment of stage Ⅲ-Ⅳ lung squamous cell carcinoma.Methods A total of 104 patients with stage Ⅲ-Ⅳ lung squamous cell carcinoma,who were admitted to the Lishui Municipal Central Hospital of China between January 2013 and August 2021,were enrolled in this study.According to the therapeutic scheme,the patients were divided into DEB-BACE group(n=41)and BACE group(n=63).For patients of DEB-BACE group,Cisplatin at 75 mg/m2 dose and gemcitabine at 1 000 mg/m2 dose(400 mg was used as loaded-drug dose)were injected through a microcatheter,which was followed by embolization with CalliSpheres microspheres loaded with 400 mg of gemcitabine.For patients of BACE group,Cisplatin at 75 mg/m2 and gemcitabatin at 1 000 mg/m2 were injected through a microcatheter,which was followed by arterial embolization with blank microspheres.Three weeks after DEB-BACE or BACE,the patients of both groups were started on intravenous chemotherapy.The primary study endpoint was overall survival(OS).The secondary study endpoints included progression-free survival(PFS),objective response rate(ORR),disease control rate(DCR),adverse reactions,and the remission rate of dyspnea.Results Of the 104 patients,63 received BACE sequential intravenous chemotherapy and 41 received DEB-BACE sequential intravenous chemotherapy.The median OS in DEB-BACE group was 23.0 moths,which was obviously longer than 12.0 months in BACE group(P=0.009).Multivariate Cox regression analysis showed that DEB-BACE treatment was an independent risk factor for OS(HR=0.59,95% CI:0.38-0.91,Log-rank test P=0.018).Meanwhile,the remission rate of dyspnea in DEB-BACE group was significantly higher than that in BACE group(57.1% vs 30.6%,P<0.043).Conclusion Compared with BACE sequential intravenous chemotherapy,DEB-BACE sequential intravenous chemotherapy can significantly prolong the survival time of patients with stage Ⅲ-Ⅳ lung squamous cell carcinoma and significantly improve the symptoms of dyspnea,which has important applications in the treatment of patients with advanced lung squamous cell carcinoma.
5.The effect of asperuloside on airway inflammation in juvenile rats with bronchial asthma by regulating the IL-6/JAK2/STAT3 signaling pathway
Yuejuan XU ; Danhong QIAN ; Xinxia MIAO ; Chunxia HU ; Jun HUA ; Jiayang MAO
Immunological Journal 2025;41(3):144-149
Objective To investigate the effects of asperuloside(ASP)on airway inflammation and the interleukin-6/Janus kinase 2/signal transducer and activator of transcription 3(IL-6/JAK2/STAT3)signaling pathway in juvenile rats with bronchial asthma.Methods A juvenile rat model of bronchial asthma was constructed and randomly separated into a Model group,low,medium,and high dose asperuloside groups(ASP-L,ASP-M,ASP-H groups),and high-dose asperuloside+pathway activator group(ASP-H+CA1 group),with 12 rats in each group.An additional 12 healthy rats were included as Control group.All rats were evaluated for lung function.The number of inflammatory cells in bronchoalveolar lavage fluid(BALF),and the levels of inflammatory factors in BALF and serum were detected.HE staining was applied to observe the pathological morphology of lung tissue.Western blot was applied to detect the expression of proteins related to the IL-6/JAK2/STAT3 signaling pathway.Results Compared with Control group,the lung tissue of rats in the Model group showed severe damage and higher levels of inflammatory cell infiltration,the PEF,Cdyn,and FEV/FVC indexes were greatly decreased,the numbers of inflammatory cells(WBC,EOS,NEU,LYM),levels of inflammatory factors(IL-1β,TNF-α,and IL-6)in BALF and serum,and the expression levels of signaling pathway proteins(IL-6,p-JAK2/JAK2,p-STAT3/STAT3)were obviously increased(P<0.05).Compared with the Model group,with the increase of ASP dosage,the degree of lung tissue damage and inflammatory cell infiltration of rats in the ASP-L,ASP-M,and ASP-H groups were significantly reduced,the PEF,Cdyn,and FEV/FVC indexes were gradually increased,the numbers of inflammatory cells(WBC,EOS,NEU,LYM),levels of inflammatory factors(IL-1β,TNF-α,and IL-6)in BALF and serum,and the expression levels of signaling pathway proteins(IL-6,p-JAK2/JAK2,p-STAT3/STAT3)were gradually decreased(P<0.05).Compared with the ASP-H group,the lung tissue of rats in the ASP-H+CA1 group showed severe damage,the infiltration of inflammatory cells increased,the PEF,Cdyn,and FEV/FVC indexes were decreased,the numbers of inflammatory cells(WBC,EOS,NEU,LYM),levels of inflammatory factors(IL-1β,TNF-α,and IL-6)in BALF and serum,and the expression levels of signaling pathway proteins(IL-6,p-JAK2/JAK2,p-STAT3/STAT3)were greatly increased(P<0.05).Conclusion Asperuloside can improve lung tissue damage,reduce inflammation levels,and improve lung ventilation function in rats with bronchial asthma.Its effect may be related to the regulation of the IL-6/JAK2/STAT3 signaling pathway.
6.Mechanisms of Gut Microbiota Influencing Reproductive Function via The Gut-Gonadal Axis
Ya-Qi ZHAO ; Li-Li QI ; Jin-Bo WANG ; Xu-Qi HU ; Meng-Ting WANG ; Hai-Guang MAO ; Qiu-Zhen SUN
Progress in Biochemistry and Biophysics 2025;52(5):1152-1164
Reproductive system diseases are among the primary contributors to the decline in social fertility rates and the intensification of aging, posing significant threats to both physical and mental health, as well as quality of life. Recent research has revealed the substantial potential of the gut microbiota in improving reproductive system diseases. Under healthy conditions, the gut microbiota maintains a dynamic balance, whereas dysfunction can trigger immune-inflammatory responses, metabolic disorders, and other issues, subsequently leading to reproductive system diseases through the gut-gonadal axis. Reproductive diseases, in turn, can exacerbate gut microbiota imbalance. This article reviews the impact of the gut microbiota and its metabolites on both male and female reproductive systems, analyzing changes in typical gut microorganisms and their metabolites related to reproductive function. The composition, diversity, and metabolites of gut bacteria, such as Bacteroides, Prevotella, and Firmicutes, including short-chain fatty acids, 5-hydroxytryptamine, γ-aminobutyric acid, and bile acids, are closely linked to reproductive function. As reproductive diseases develop, intestinal immune function typically undergoes changes, and the expression levels of immune-related factors, such as Toll-like receptors and inflammatory cytokines (including IL-6, TNF-α, and TGF-β), also vary. The gut microbiota and its metabolites influence reproductive hormones such as estrogen, luteinizing hormone, and testosterone, thereby affecting folliculogenesis and spermatogenesis. Additionally, the metabolism and absorption of vitamins can also impact spermatogenesis through the gut-testis axis. As the relationship between the gut microbiota and reproductive diseases becomes clearer, targeted regulation of the gut microbiota can be employed to address reproductive system issues in both humans and animals. This article discusses the regulation of the gut microbiota and intestinal immune function through microecological preparations, fecal microbiota transplantation, and drug therapy to treat reproductive diseases. Microbial preparations and drug therapy can help maintain the intestinal barrier and reduce chronic inflammation. Fecal microbiota transplantation involves transferring feces from healthy individuals into the recipient’s intestine, enhancing mucosal integrity and increasing microbial diversity. This article also delves into the underlying mechanisms by which the gut microbiota influences reproductive capacity through the gut-gonadal axis and explores the latest research in diagnosing and treating reproductive diseases using gut microbiota. The goal is to restore reproductive capacity by targeting the regulation of the gut microbiota. While the gut microbiota holds promise as a therapeutic target for reproductive diseases, several challenges remain. First, research on the association between gut microbiota and reproductive diseases is insufficient to establish a clear causal relationship, which is essential for proposing effective therapeutic methods targeting the gut microbiota. Second, although gut microbiota metabolites can influence lipid, glucose, and hormone synthesis and metabolism via various signaling pathways—thereby indirectly affecting ovarian and testicular function—more in-depth research is required to understand the direct effects of these metabolites on germ cells or granulosa cells. Lastly, the specific efficacy of gut microbiota in treating reproductive diseases is influenced by multiple factors, necessitating further mechanistic research and clinical studies to validate and optimize treatment regimens.
7.Establishment and application of JEV,PRRSV and CSFV TaqMan triple RT-qPCR method
Li ZHANG ; Deyuan TANG ; Zhiyong ZENG ; Bin WANG ; Shenglin YUAN ; Xu CHEN ; Zhengbo LIAO ; Piao ZHOU ; Song HE ; Yinming MAO ; Wenwen HU ; Min ZHOU ; Fangxin GAO
Chinese Journal of Veterinary Science 2025;45(9):1824-1833
To establish a TaqMan-based multiplex RT-qPCR method for the identification of Japa-nese encephalitis virus(JEV),Porcine reproductive and respiratory syndrome virus(PRRSV),and Classical swine fever virus(CSFV),this study designed and synthesized three pairs of specific primers and probes based on the conserved sequences of JEV E,PRRSV ORF6,and CSFV E2 a-vailable in the NCBI GenBank.By optimizing the reaction system and protocol,a multiplex RT-qPCR method for detecting these three viruses was developed and applied to the detection of clini-cal samples.The results showed that the established TaqMan multiplex RT-qPCR specifically am-plified the gene fragments of JEV,PRRSV,and CSFV,and did not amplify other non-target genes,indicating good specificity of the method.Intra-assay and inter-assay repeatability tests showed that the coefficient of variation(Cv)values were all below 3%,demonstrating that the method has ex-cellent repeatability.Sensitivity tests revealed that the minimum detectable amount for the recom-binant plasmids of the three viruses was 100 copies/pL.Using the established method,a total of 969 samples,including blood,aborted fetuses,semen,and deceased pigs,from 26 pig farms in Guizhou Province were tested.The detection rates were 34.3%(332/969)for JEV,28.3%(274/969)for PRRSV,and 19.8%(192/969)for CSFV.The co-infection rates were 10.1%(98/969)for JEV and PRRSV,12.1%(117/969)for JEV and CSFV,and 14.6%(141/969)for CSFV and PRRSV.Additionally,the triple co-infection rate of JEV,PRRSV,and CSFV was 7.9%(77/969).These results indicate that the TaqMan multiplex RT-qPCR method developed in this study is ef-fective for detecting these three viruses in pig farms,providing technical support for identifying vi-ral causes of reproductive disorders.
8.Development and application of pilot hypoxia endurance testing system
Lin-xia LI ; Guo-yun MAO ; Ming-rui HU ; Jia-ling XU ; Yao-xuan JI ; Na ZHI ; Yan-qing BAI ; Yun-ying WANG
Chinese Medical Equipment Journal 2025;46(10):23-28
Objective To develop a hypoxia endurance testing system for aviation physiological training of pilots.Methods The hypoxia endurance testing system comprised a low-oxygen mixed gas generator,a pressurization system for low-oxygen mixed gas and a personal breathing apparatus.The low-oxygen mixed gas generator consisted of a main unit composed of an air compressor,a filter,a buffer tank,polymer membrane,a control module,sensors and regulators,wire cables,supporting hoses,etc.;the pressurization system for low-oxygen mixed gas was made up of a protective box,a cooling fan,a motor and a driver,a control module,a solenoid valve,a convergence block,a pressure gauge,etc.;the personal breating apparatus was composed of a gas cylinder,a pressure reducer,an oxygen supply regulator,etc.Forty-eight subjects were selected for hypoxia exposure tests to verify the effectiveness of the system.Results The system developed had the functions of low-oxygen gas preparation,pressurized filling and hypoxia experiment,and the experimental results indicated the acute hypoxia exposure by the system significantly caused signs and symptoms of hypoxia and weakened physiological functions.Conclusion The system developed gains advantages in high accuracy of gas volume fraction control,safety and remarkable effect of simulated hypoxia,and can be an effective tool for acute high-altitude hypoxia testing and training of pilots.[Chinese Medical Equipment Journal,2025,46(10):23-28]
9.National bloodstream infection bacterial resistance surveillance report 2023: Gram-positive bacteria
Chaoqun YING ; Jinru JI ; Zhiying LIU ; Qing YANG ; Haishen KONG ; Jiangqin SONG ; Hui DING ; Yanyan LI ; Yuanyuan DAI ; Haifeng MAO ; Pengpeng TIAN ; Lu WANG ; Yongyun LIU ; Yizheng ZHOU ; Jiliang WANG ; Yan JIN ; Donghong HUANG ; Hongyun XU ; Peng ZHANG ; Xinhua QIANG ; Hong HE ; Lin ZHENG ; Junmin CAO ; Zhou LIU ; Ying HUANG ; Yan GENG ; Haiquan KANG ; Dan LIU ; Guolin LIAO ; Lixia ZHANG ; Fenghong CHEN ; Yanhong LI ; Baohua ZHANG ; Haixin DONG ; Xiaoyan LI ; Donghua LIU ; Qiuying ZHANG ; Xuefei HU ; Liang GUO ; Sijin MAN ; Dijing SONG ; Rong XU ; Youdong YIN ; Kunpeng LIANG ; Aiyun LI ; Zhuo LI ; Hongxia HU ; Guoping LU ; Jinhua LIANG ; Qiang LIU ; Yinqiao DONG ; Jilu SHEN ; Shuyan HU ; Liang LUAN ; Jian LI ; Ling MENG ; Dengyan QIAO ; Xiusan XIA ; Bo QUAN ; Dahong WANG ; Chunhua HAN ; Xiaoping YAN ; Fei LI ; Shifu WANG ; Ping SHEN ; Yunbo CHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2025;18(2):118-132
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
10.National bloodstream infection bacterial resistance surveillance report (2023) : Gram-negative bacteria
Jinru JI ; Zhiying LIU ; Chaoqun YING ; Qing YANG ; Haishen KONG ; Jiangqin SONG ; Hui DING ; Yanyan LI ; Yuanyuan DAI ; Haifeng MAO ; Pengpeng TIAN ; Lu WANG ; Yongyun LIU ; Yizheng ZHOU ; Jiliang WANG ; Yan JIN ; Donghong HUANG ; Hongyun XU ; Peng ZHANG ; Xinhua QIANG ; Hong HE ; Lin ZHENG ; Junmin CAO ; Zhou LIU ; Ying HUANG ; Yan GENG ; Haiquan KANG ; Dan LIU ; Guolin LIAO ; Lixia ZHANG ; Fenghong CHEN ; Yanhong LI ; Baohua ZHANG ; Haixin DONG ; Xiaoyan LI ; Donghua LIU ; Qiuying ZHANG ; Xuefei HU ; Liang GUO ; Sijin MAN ; Dijing SONG ; Rong XU ; Youdong YIN ; Kunpeng LIANG ; Aiyun LI ; Zhuo LI ; Hongxia HU ; Guoping LU ; Jinhua LIANG ; Qiang LIU ; Yinqiao DONG ; Jilu SHEN ; Shuyan HU ; Liang LUAN ; Jian LI ; Ling MENG ; Dengyan QIAO ; Xiusan XIA ; Bo QUAN ; Dahong WANG ; Chunhua HAN ; Xiaoping YAN ; Fei LI ; Shifu WANG ; Ping SHEN ; Yunbo CHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2025;18(1):47-62
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.

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