1.Differences in deltamethrin resistance and kdr gene mutation in Culex tritaeniorhynchus population in and outside the Yellow Sea wetland
Xiao-er ZHANG ; Zhi-ming WU ; Ye TIAN ; Qian CUI ; Yu-qian JI ; Huan WANG ; Shu-juan YANG ; Yi-chao ZHAO ; Yu WANG ; Hua-yu YIN ; Yu DING ; Guo-jin YAN ; Min-sen ZHAO ; Shou-gang ZHANG ; Bing-dong SONG ; Hong-na CHEN ; Jian GAO ; Wei-fang YANG ; Yu-fu ZHANG ; Hui LIU ; Hong-liang CHU
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):101-107
Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.
2.PPARα activation alleviates lithocholic acid-induced liver injury by inhibiting pyroptosis
Hang-Fei Liang ; Chuo-Ying Mai ; Xuan Li ; Jia-Ning Tian ; Hai-Guo Su ; Min Huang ; Jian-Hong Fang ; Hai-Tao Wang ; Xiao Yang ; Hui-Chang Bi
Liver Research 2026;10(2):177-188
Background and aims
The mechanism of cholestatic liver injury (CLI) is unclear, and effective therapies are lacking. While peroxisome proliferator-activated receptor alpha (PPARα) agonists show potential hepatoprotective effect and pyroptosis is implicated in hepatocellular damage, how PPARα activation mitigates lithocholic acid (LCA)-induced pyroptosis remains unknown.
Methods
The hepatoprotective effect of PPARα agonists was evaluated in a mouse model of intrahepatic cholestasis induced by LCA. Liver injury was assessed via serum biochemistry, hematoxylin and eosin and TUNEL staining, and electron microscopy. Pyroptosis pathways were analyzed using real-time quantitative polymerase chain reaction, Western blot, and co-immunoprecipitation.
Results
Combined morphological, histopathological, and biochemical analyses confirmed that PPARα activation protects against CLI. Compared with LCA treatment alone, PPARα activation significantly attenuated the elevation of serum lactate dehydrogenase (LDH), the increased TUNEL-positive cells, and the formation of hepatocyte membrane pores. Mechanistically, PPARα activation suppressed both NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis and apoptosis protease-activating factor-1 (APAF-1)/CASPASE-3/GSDME-mediated pyroptosis. Furthermore, PPARα agonist pretreatment inhibited activation of the nuclear factor-kappa B (NF-κB) and forkhead box O1 (FOXO1) signaling pathways.
Conclusions
PPARα protects against LCA-induced CLI by inhibiting both NLRP3 inflammasome-mediated pyroptosis associated with NF-κB and APAF-1/CASPASE-3/GSDME-mediated pyroptosis associated with the FOXO1 signaling pathway.
3.Molecular epidemiological survey of Giardia and Cryptosporidium in Ochotona curzoniae in Zoige County,Sichuan Province
Hong-xi CHEN ; Yang XIANG ; Ri-hong JIKE ; Tian-xiang CHEN ; Dong-bo YUAN ; Liang-quan ZHU ; Li-li HAO
Chinese Journal of Zoonoses 2025;41(3):331-338
This study was aimed at investigating infections with Giardia and Cryptosporidium in Ochotona curzoniae in Zoige County,Sichuan Province.O.curzoniae were captured in five townships of Zoige County(Dazhasi,Axi,Hongxing,Tangke,and Maixi)between March and December of 2023.DNA from the gastrointestinal contents was subjected to nested PCR to amplify Giardia bg,gdh,and tpi genes,and the Cryptosporidium SSU rRNA gene.The sequences of PCR-PCR products were analyzed and compared.Phylogenetic trees were constructed to determine the protozoa species and genotypes.A total of 114 O.curzoniae animals were captured,among which 44 samples showed bg gene positivity,and 14 samples showed gdh gene positivity for Giardia.The total detection rate was 43.9%(50/114),and two assemblages were detected(assem-blage E and a new assemblage tentatively termed assemblage OC1);the positivity rate for Cryptosporidium was 7.0%(8/114),and three new genotypes were observed.Mixed infection with Cryptosporidium and Giardia was present in some sam-ples,with a detection rate of 3.5%(4/114).Giardia lamblia and Giardia sp.(REG-1,REG-2)were prevalent in O.curzoni-ae in Zoige County in Sichuan province;assemblage E was the dominant assemblage,and the new assemblage OC1 was pres-ent;and Cryptosporidium sp.(REG-1,REG-2,and REG-3)were identified.In summary,future monitoring of Giardia and Cryptosporidium should be further strengthened in Zoige to provide detailed data for promoting local public health.
4.Efficacy and safety of a facilitated percutaneous coronary intervention with half-dose recombinant staphylokinase in ST-segment elevation myocardial infarction
Tian-yu WU ; Wen-hao ZHANG ; Peng-sheng CHEN ; Chen LI ; Tian WU ; Zhan LÜ ; Tong WANG ; Kun LIU ; Zhi-wen TAO ; Xiao-xuan GONG ; Liang YUAN ; Yong LI ; Bo CHEN ; Xin CHEN ; Zeng-guang CHEN ; Nai-quan YANG ; Yuan-yuan SANG ; Xiao-yan WANG ; Bai-hong LI ; Li ZHU ; Guo-yu WANG ; Xin ZHAO ; Chuan LU ; Jun JIANG ; Rui-na HAO ; Chun-jian LI
Chinese Journal of Interventional Cardiology 2025;33(8):431-438
Objective To investigate the clinical efficacy and safety of facilitated percutaneous coronary intervention(PCI)with half-dose recombinant staphylokinase(r-SAK)in patients with ST-segment elevation myocardial infarction(STEMI)who are expected to undergo PCI within 120 minutes.Methods From October 2021 to August 2022,a total of 200 STEMI patients in eight centers were included and randomly assigned in a 1﹕1 ratio to either r-SAK group or control group.Patients received loading doses of aspirin and ticagrelor and intravenous heparin and were randomized to receive an intravenous bolus of either 5 mg r-SAK or normal saline prior to PCI.The outcomes were set as ST-segment resolution(STR)at 60-90 minutes after PCI,the proportion and transition of pathological Q waves on the 5th day after PCI,and the proportion of high-sensitivity cardiac troponin T(hs-cTnT)peaking within 12 hours of onset.The safety outcome was major bleeding events defined as Bleeding Academic Research Consortium(BARC)≥type 3 bleeding during hospitalization.Results Compared with the control group,the r-SAK group had a higher proportion of STR≥70%within 60-90 minutes after PCI(58.3%vs.40.3%,P=0.009);a lower proportion of pathological Q waves(59.1%vs.74.1%,P=0.040);a lower rate of Q wave progression(14.8%vs.43.2%,P<0.001);a higher rate of Q wave disappearance(12.5%vs.3.7%,P=0.027);and a higher proportion of hs-cTnT peaking within 12 hours of symptom onset[31/40(77.5%)vs.17/33(51.5%),P=0.027].Regarding the safety outcome,no significant difference in BARC≥type 3 bleeding was found between the two groups during hospitalization(P>0.05).Conclusions For STEMI patients who were expected to undergo primary PCI within 120 minutes of symptom onset,the facilitated PCI with half-dose r-SAK significantly increased the proportion of STR≥70%at 60-90 minutes after PCI,reduced the formation of pathological Q waves,and shortened the time to peak hs-cTnT,without increasing the risk of bleeding,which should be an alternative reperfusion strategy worthy of further study.
5.Effects of Hedysarum polybotrys polysacchcaide on FXR-FGF19 signal pathway in diabetes rats
Lei ZHANG ; Sheng-fang WAN ; Ya-ling LI ; Qian-kun LIANG ; Yi-hong TIAN ; Xin-xin MA ; Qian GUO
The Chinese Journal of Clinical Pharmacology 2025;41(1):76-80
Objective To study the effects of Hedysarum polysaccharides polysaccharide(HPS)on the farnesoid X receptor(FXR)-fibroblast growth factor-19(FGF19)signaling pathway of diabetes rats.Methods Twelve Wistar male rats were randomly selected as the normal group,and the other rats were fed with a single intraperitoneal injection of streptozotocin(50 mg·kg-1 STZ)and a high sugar and high-fat diet to replicate the diabetes rat model.Model rats were randomly divided into model group,positive control group(given 400 mg·kg-1·d-1 suspension of Bifidobacterium quadruplex live bacterial tablets by gavage),experimental-H,-M,-L groups(given 200,100,and 50 mg·kg-1·d-1 doses of HPS suspension by gavage);normal group,and model group were given equal volume of purified water by gavage once a day for 8 consecutive weeks.Glucose(Glu)was detected by a blood glucose meter;and serum total glyceride(TG)and total cholesterol(TC)were detected by enzyme-linked immunosorbent assay reagent kit;the expressions of FXR、fibroblast growth factor receptors 4(FGFR4)relative mRNA expression level and protein were detected by real-time fluorescence quantitative polymerase chain reaction method and Western blot.Results The Glu concentrations in the normal group,model group,positive control group,and experimental-H groups were(7.66±0.61),(29.25±1.64),(23.31±3.02)and(19.31±5.13)mmol·L-1,respectively;the TG content were(957.00±113.73),(1 345.00±246.44),(958.00±96.53)and(964.00±130.22)μmol·L-1,respectively;the TC content were(161.65±4.53),(302.19±5.35),(236.09±5.14)and(165.58±2.58)μmol·L-1,respectively;the expression of FXR relative mRNA expression level were 1.00±0.06,0.48±0.02,0.67±0.04 and 0.92±0.04,respectively;the expression of FGFR4 relative mRNA expression level were 1.00±0.04,0.17±0.01,0.48±0.04 and 0.41±0.03;respectively.The above indexes of the model group were compared with the control group,and the above indexes of the control group and the experimental-H group were compared with the model group,and the differences were statistically significant(all P<0.01).Conclusion HPS improves blood sugar,lowers blood lipids,and protects liver and intestinal tissues,possibly by regulating the FXR-FGF19 signaling pathway in intestinal tissue,and regulating bile acid synthesis.
6.Engineering CHO Cell Lines to Stably Express B4GALT1,ST6GAL1,and GnTⅢ with Site-directed Integration
Xian-Hong LI ; Run-Qing JIA ; You-Liang WANG ; Wei-Ling MAN ; Tian-Hao ZHU ; Xin-Long YAN ; Yan-Li LIN
Chinese Journal of Biochemistry and Molecular Biology 2025;41(4):576-585
Glycoengineering was carried out in the mammalian cell line CHO for the production of pro-tein-based drugs.Firstly,the genome sequence of the Rosa26 locus of CHO cells was determined,the gRNA sequences were designed,and the landing pad was integrated into the Rosa26 locus of CHO cells by CRISPR/Cas9 technology.Three targeting vectors co-expressed by glycosyltransferases,which are β-1,4 galactosyltransferase(B4GALT1),α-2,6-sialyltransferase 1(ST6GAL1)and N-acetaminoglycosyl-transferase Ⅲ(GnT Ⅲ),were constructed by overlapping PCR and seamless ligation technology,and the three glycosyltransferase genes were integrated into the CHO Rosa26 locus by Cre enzyme-mediated cassette exchange technology.PCR confirmed that three glycosyltransferases had been successfully site-directed integrated into the Rosa26 site.The mRNA expression levels of the three glycosyltransferases were more than 50 000-fold by qRT-PCR,and the protein expression levels of the three glycosyltrans-ferases were more than 4-fold via western blotting(P<0.001).A CHO-engineered cell line with three glycosyltransferases integrated into Rosa26 site was successfully constructed.
7.Effect of Electroacupuncture on TGF-β1/Smads Signaling Pathway and Epithelial-Mesenchymal Transition-related Protein Expression in Rats with Neurogenic Bladder After Spinal Cord Injury
Xiaojing LUO ; Chuning TIAN ; Lifen ZHAN ; Qian LI ; Roujun LIANG ; Lubo XIAO ; Yue ZHUO ; Kun AI ; Ming XU ; Hong ZHANG
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(10):120-126
Objective To observe the effects of electroacupuncture(EA)on TGF-β1/Smads signaling pathway and epithelial-mesenchymal transition(EMT)related proteins in rats with neurogenic bladder(NB)after spinal cord injury;To explore the possible mechanism of EA in improving NB fibrosis.Methods Totally 36 female SD rats were randomly selected,with 10 rats in the sham-operation group and the remaining 26 rats undergoing complete transection of the spinal cord beneath the T8 vertebrae to establish a NB rat model.The modeling rats were randomly divided into model group and EA group,with 10 rats in each group.EA group was applied to"Ciliao","Zhongji"and"Sanyinjiao",20 min per time,once a day for 7 days.The general condition of the rats in each group was observed,the ultrasound index of the bladder was detected by ultrasound technique,the bladder function of the rats was detected by urodynamics,the body mass of the rats and the wet weight of the bladder were recorded,and the bladder index was calculated.HE staining was used to observe bladder tissue morphology,the degree of bladder tissue fibrosis and bladder wall thickness were detected by Masson staining.The positive expressions of E-cadherin,N-cadherin and Vimentin in bladder tissue were detected by immunohistochemistry.The protein expressions of TGF-β1,p-Smad2/3,E-cadherin,N-cadherin and Vimentin were detected by Western blot.Results Compared with the sham-operation group,the upper and lower diameter,anteroposterior diameter,transverse diameter,bladder volume of the model group significantly increased(P<0.001),the maximum bladder pressure,leak point pressure difference,perfusion time and maximum bladder capacity significantly increased(P<0.001),the bladder index increased significantly(P<0.001),the bladder epithelial cells were thickened and arranged irregularly,the bladder collagen volume fraction and bladder wall thickness significantly increased(P<0.001),the expressions of TGF-β1,p-Smad2/3,N-cadherin and Vimentin in bladder tissue increased(P<0.01),and the expression of E-cadherin decreased(P<0.001).Compared with the model group,the upper and lower diameter,anteroposterior diameter,transverse diameter,bladder volume of the EA group decreased significantly(P<0.05),the maximum bladder pressure,leak point pressure difference,perfusion time and maximum bladder capacity significantly decreased(P<0.05),the bladder index significantly decreased(P<0.05),the thickness of the bladder epithelial cell layer became thinner and arranged more neatly,and the bladder collagen volume fraction and bladder wall thickness of the bladder were significantly reduced(P<0.05),the expressions of TGF-β1,p-Smad2/3,N-cadherin and Vimentin in bladder tissue significantly decreased(P<0.05),and the expression of E-cadherin significantly increased(P<0.05).Conclusion EA may reduce the EMT of bladder epithelial cells and decrease the degree of bladder tissue fibrosis by inhibiting the activation of the TGF-β1/Smads signaling pathway,thereby improving bladder function in NB rats after spinal cord injury.
8.Engineering CHO Cell Lines to Stably Express B4GALT1,ST6GAL1,and GnTⅢ with Site-directed Integration
Xian-Hong LI ; Run-Qing JIA ; You-Liang WANG ; Wei-Ling MAN ; Tian-Hao ZHU ; Xin-Long YAN ; Yan-Li LIN
Chinese Journal of Biochemistry and Molecular Biology 2025;41(4):576-585
Glycoengineering was carried out in the mammalian cell line CHO for the production of pro-tein-based drugs.Firstly,the genome sequence of the Rosa26 locus of CHO cells was determined,the gRNA sequences were designed,and the landing pad was integrated into the Rosa26 locus of CHO cells by CRISPR/Cas9 technology.Three targeting vectors co-expressed by glycosyltransferases,which are β-1,4 galactosyltransferase(B4GALT1),α-2,6-sialyltransferase 1(ST6GAL1)and N-acetaminoglycosyl-transferase Ⅲ(GnT Ⅲ),were constructed by overlapping PCR and seamless ligation technology,and the three glycosyltransferase genes were integrated into the CHO Rosa26 locus by Cre enzyme-mediated cassette exchange technology.PCR confirmed that three glycosyltransferases had been successfully site-directed integrated into the Rosa26 site.The mRNA expression levels of the three glycosyltransferases were more than 50 000-fold by qRT-PCR,and the protein expression levels of the three glycosyltrans-ferases were more than 4-fold via western blotting(P<0.001).A CHO-engineered cell line with three glycosyltransferases integrated into Rosa26 site was successfully constructed.
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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