Objective:The genotoxicity risk of graphene artificial nerve sheath conduit was systematically evaluated to provide scientific evidence for their clinical safety and to establish methodological references for the genotoxicity assessment of nanomaterial medical devices.Methods:The potential effects of graphene artificial nerve sheath conduit on genetic and chromosomal endpoints were analyzed by integrating bacterial reverse mutation assays,in vitro chromosome aberration assays,mouse lymphoma cell TK gene mutation tests,and mammalian erythrocyte Pig-a gene mutation assays.Results:In the bacterial reverse mutation assay,all plates showed good background growth.There was no significant difference in the average number of revertant colonies between the test group and the negative control group,with a ratio around 1.0.In the in vitro chromosome aberration assay,the chromosomal aberration rate in the test group was less than 5％,showing no significant increase compared to the negative control group.In the mouse lymphoma cell TK gene mutation assay,the mutation frequency in the test group was less than twice that of the negative control group,with no significant difference.In the mammalian erythrocyte Pig-a gene mutation assay,the mutation frequencies of erythrocytes and reticulocytes in the test group were both less than 3× 10-6,showing no significant difference compared to the negative control group.Conclusions:Graphene artificial nerve sheath conduit exhibited no detectable genotoxicity under the tested conditions,the research results can provide reference and guidance for the genotoxicity evaluation of nanomaterial medical devices.

Objective:An in vivo mammalian hepatocyte Unscheduled DNA Synthesis(UDS)test was used to evaluate the genotoxicity of Cross-linked Sodium Hyaluronate Gel and Bone Repair Materials,providing experimental evidence for establishing a UDS testing method for medical devices and materials.Methods:0.9％sodium chloride injection and cottonseed oil were used as the solvent for test materials and negative control,respectively.N-dimethylnitrosamine(NDMA)was used as the positive control for the early sampling times,and 2-acetylaminofluorene(2-AAF)was used as the positive control for the late sampling times.SD rats were administered a single dose for toxic exposure,and liver tissues were collected at 4 h and 16 h,respectively.Hepatocytes were isolated using collagenase perfusion.After labeling with 5-ethynyl-2'-deoxyuridine(EdU),and the net average fluorescence intensity(NAFI)of cell nuclei and nucleoplasm was measured by fluorescence microscope.Data from 50 cells were used to analyze the DNA repair level.Results:Compared with the negative control groups,the positive control groups(NDMA and 2-AAF)showed highly statistically significant differences in NAFI(P＜0.01),indicating successful induction of DNA damage.There was no statistically significant differences between the cross-linked sodium hyaluronate gel groups,bone repair material groups and the negative control group(P＞0.05),suggesting that these materials did not significantly induce DNA damage under the experimental conditions.Conclusion:This study first applied EdU labeling technology to the in vivo hepatic UDS assay,achieving non-radioactive labeling through click chemistry reactions.Under the conditions of this study,cross-linked sodium hyaluronate gel and bone repair materials did not exhibit genotoxicity.In the follow-up,the sample range can be expanded and the observation period can be prolonged to further improve the genotoxicity evaluation system of medical devices.

Human carboxylesterase 2A (hCES2A) plays pivotal roles in prodrug activation and hydrolytic metabolism of ester-bearing chemicals. Targeted inhibition of intestinal hCES2A represents a feasible strategy to mitigate irinotecan-triggered gut toxicity (ITGT), but the orally active, selective, and efficacious hCES2A inhibitors are rarely reported. Here, a novel drug-like hCES2A inhibitor was developed via three rounds of structure-based drug design (SBDD) and structural optimization. Initially, donepezil was identified as a moderate hCES2A inhibitor from 2000 US Food and Drug Administration (FDA)-approved drugs. Following two rounds of SBDD and structural optimization, a donepezil derivative (B7) was identified as a strong reversible hCES2A inhibitor. Subsequently, nine B7 carbamates were rationally designed, synthesized and biologically assayed. Among all synthesized carbamates, C3 showed the most potent time-dependent inhibition on hCES2A (IC₅₀ = 0.56 nmol/L), excellent specificity and favorable drug-like properties. C3 could covalently modify the catalytic serine of hCES2A with high selectivity, while this agent also showed favorable safety profiles, high intestinal exposure, and impressive effects for ameliorating ITGT in both human intestinal organoids and tumor-bearing mice. Collectively, this study showcases a rational strategy for developing drug-like and serine-targeting covalent inhibitors against target serine hydrolase(s), while C3 emerges as a promising orally active drug candidate for ameliorating ITGT.

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:An in vivo mammalian hepatocyte Unscheduled DNA Synthesis(UDS)test was used to evaluate the genotoxicity of Cross-linked Sodium Hyaluronate Gel and Bone Repair Materials,providing experimental evidence for establishing a UDS testing method for medical devices and materials.Methods:0.9％sodium chloride injection and cottonseed oil were used as the solvent for test materials and negative control,respectively.N-dimethylnitrosamine(NDMA)was used as the positive control for the early sampling times,and 2-acetylaminofluorene(2-AAF)was used as the positive control for the late sampling times.SD rats were administered a single dose for toxic exposure,and liver tissues were collected at 4 h and 16 h,respectively.Hepatocytes were isolated using collagenase perfusion.After labeling with 5-ethynyl-2'-deoxyuridine(EdU),and the net average fluorescence intensity(NAFI)of cell nuclei and nucleoplasm was measured by fluorescence microscope.Data from 50 cells were used to analyze the DNA repair level.Results:Compared with the negative control groups,the positive control groups(NDMA and 2-AAF)showed highly statistically significant differences in NAFI(P＜0.01),indicating successful induction of DNA damage.There was no statistically significant differences between the cross-linked sodium hyaluronate gel groups,bone repair material groups and the negative control group(P＞0.05),suggesting that these materials did not significantly induce DNA damage under the experimental conditions.Conclusion:This study first applied EdU labeling technology to the in vivo hepatic UDS assay,achieving non-radioactive labeling through click chemistry reactions.Under the conditions of this study,cross-linked sodium hyaluronate gel and bone repair materials did not exhibit genotoxicity.In the follow-up,the sample range can be expanded and the observation period can be prolonged to further improve the genotoxicity evaluation system of medical devices.

Objective:The genotoxicity risk of graphene artificial nerve sheath conduit was systematically evaluated to provide scientific evidence for their clinical safety and to establish methodological references for the genotoxicity assessment of nanomaterial medical devices.Methods:The potential effects of graphene artificial nerve sheath conduit on genetic and chromosomal endpoints were analyzed by integrating bacterial reverse mutation assays,in vitro chromosome aberration assays,mouse lymphoma cell TK gene mutation tests,and mammalian erythrocyte Pig-a gene mutation assays.Results:In the bacterial reverse mutation assay,all plates showed good background growth.There was no significant difference in the average number of revertant colonies between the test group and the negative control group,with a ratio around 1.0.In the in vitro chromosome aberration assay,the chromosomal aberration rate in the test group was less than 5％,showing no significant increase compared to the negative control group.In the mouse lymphoma cell TK gene mutation assay,the mutation frequency in the test group was less than twice that of the negative control group,with no significant difference.In the mammalian erythrocyte Pig-a gene mutation assay,the mutation frequencies of erythrocytes and reticulocytes in the test group were both less than 3× 10-6,showing no significant difference compared to the negative control group.Conclusions:Graphene artificial nerve sheath conduit exhibited no detectable genotoxicity under the tested conditions,the research results can provide reference and guidance for the genotoxicity evaluation of nanomaterial medical devices.

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.

The PCR-amplified severe fever with thrombocytopenia syndrome virus(SFTSV)Gn-DⅢ-Ⅲ gene was inserted into the pET-30a(+)prokaryotic expression vector to generate the re-combinant plasmid pET-SFTSV-Gn-D Ⅲ-Ⅲ.The plasmid was transformed into E.coli BL21(DE3)for Gn-DⅢ-m protein expression and the expression conditions were optimized.The Gn-DⅢ-Ⅲ protein purified with Ni-NTA column affinity chromatography was applied as the captured antigen to establish an indirect ELISA method for the detection of SFTSV antibody.The results demonstrated that the recombinant plasmid pET-SFTSV-Gn-D Ⅲ-Ⅲ was successfully constructed as identified by PCR and sequencing.The recombinant protein SFTSV Gn-D m-Ⅲ was soluble ex-pression in E.coli under the optimal induction conditions of 0.4 mmol/L IPTG at 25 ℃ for 4 h,and the protein purity was 91.77％after purification by Ni-NTA column.The optimal reaction con-ditions for the indirect ELISA of SFTSV antibody were as follows:coating antigen concentration(5 μg/mL),primary antibody(incubation at 37 ℃ for 1.5 h),and secondary antibody(diluted 1:10 000 and incubated at 37 ℃ for 1 h).The established method had no cross-reactivity with Rift Valley fever virus(RVFV),Ebola virus(EBOV),and tick-borne encephalitis virus(TBEV)posi-tive sera.The method had a high sensitivity,with P/N＞2.1 for SFTSV-positive sera diluted to 81920.Coefficients of variation for intra-and inter-batch reactions were less than 10％.Detection of four SFTSV-infected human clinical serum samples showed the serum samples from patients in re-mission were tested as positive(P/N＞2.1),while serum samples from patients with multiple or-gan failure were detected as negative(P/N＜2.1).The results indicated that the SFTSV Gn-D Ⅲ-Ⅲ protein was successfully expressed and purified,and it was used as the coating protein to estab-lish an indirect ELISA assay for SFTSV antibody,which possesses good specificity,sensitivity and reproducibility.This method might be applied to detect human SFTSV clinical serum samples.