Objective : To explore the role of lysophosphatidylcholine acyltransferase 3(LPCAT3) in Erastin-induced ferroptosis of acute myeloid leukemia(AML) cells and its related molecular regulatory mechanisms. Methods : Tetrazolium salt(MTS) method was used to detect the sensitivity of different AML cells to the classic ferroptosis inducer Erastin, real time quantitative polymerase chain reaction(qPCR) was used to detect the basal expression level ofLPCAT3mRNA, and the correlation between them was analyzed. Lentivirus-mediatedLPCAT3overexpression AML cell lines(OE group) and negative control lines(NC group) were constructed. After Erastin intervention, MTS, flow cytometry, and micromethods were used to detect cell viability, lipid reactive oxygen species(ROS), and Malondialdehyde(MDA), respectively. qPCR and Western blot were used to detect unfolded protein response(UPR) classic pathway signaling molecules(PERK, ATF4, GRP78, etc.) expression levels. The above ferroptosis-related indicators were detected after combined intervention with the UPR inhibitor 4-phenylbutyric acid(4-PBA), and the regulatory relationship was analyzed. Results : Four different types of AML cells had different sensitivities to ferroptosis, among which K562 cells were relatively insensitive. The IC50of the four types of AML cells to Erastin was negatively correlated with the expression level ofLPCAT3(r=-0.919,P<0.001). After Erastin intervention, the cell viability of K562 cells in the OE group was significantly inhibited by Erastin compared with the NC group(P<0.001), and the levels of lipid ROS and MDA increased(P<0.001). The results of qPCR and Western blot showed that, compared with the NC group, the mRNA and protein expression of UPR classic pathway moleculesPERK,ATF4, andGRP78mRNA and protein increased in the OE group(P<0.01). After inhibiting the UPR pathway by 4-PBA, the viability of K562 cells decreased(P<0.01), and lipid ROS and MDA levels increased(P<0.01) compared with the uninhibited state. Conclusion Overexpression ofLPCAT3can promote ferroptosis in K562 cells, and this process is negatively regulated by the classical UPR pathway PERK/ATF.

AIM:This study investigated the role of solute carrier family 7 member 11(SLC7A11)in sul-fasalazine(SAS)-induced ferroptosis in acute myeloid leukemia(AML)cells,focusing on the inhibitory effect of nuclear factor E2-related factor 2(NRF2)nuclear translocation-mediated activation of SLC7A11 on ferroptosis and its underlying mechanisms.METHODS:SAS-induced proliferation in AML cell lines,Kasumi-1 and THP-1,was assessed using the MTS assay.Cell death inhibitors were employed to determine the mode of cell death.Lipid reactive oxygen species(ROS)levels were measured by flow cytometry;Fe2+,malonodialdehyde(MDA),glutathione(GSH)levels,and glutathione per-oxidase 4(GPX4)activity were assessed using micromethods.Quantitative PCR(qPCR)was performed to evaluate changes in SLC7A11 mRNA during SAS-induced ferroptosis,while Western blot measured SLC7A11 and GPX4 protein levels.Moreover,Western blot assessed NRF2 nuclear translocation post-SAS treatment.The NRF2 inhibitor ML385 was used to validate these effects.SLC7A11 mRNA and protein levels were then measured following combined SAS and ML385 treatment via qPCR and Western blot.Cell viability and ferroptosis-related indices were evaluated under the same treatment conditions.Furthermore,a shRNA vector targeting SLC7A11 was constructed to assess changes in cell viability and ferroptosis markers after SLC7A11 knockdown with SAS.GPX4 protein levels were examined following SLC7A11 knockdown.RESULTS:SAS significantly inhibited the proliferation of Kasumi-1 and THP-1 cells at 200 μmol/L and 300 μmol/L,respectively(P<0.05).Only ferroptosis inhibitors(Fer-1 and DFO)significantly reversed SAS-induced cy-totoxicity(P<0.01).SAS increased lipid ROS,Fe2+,and MDA levels(P<0.01),while reducing GSH and GPX4 activity(P<0.01).The mRNA and protein expressions of SLC7A11 increased during SAS-induced ferroptosis(P<0.01),where-as GPX4 protein decreased significantly(P<0.01).SAS significantly increased the nuclear-to-cytoplasmic NRF2 ratio(P<0.01),which decreased upon co-treatment with ML385(P<0.05).Following SAS and ML385 co-treatment,both SLC7A11 mRNA and protein levels were downregulated(P<0.01).This combination treatment further reduced AML cell viability(P<0.01),an effect reversed by Fer-1 and DFO(P<0.01).Compared with SAS alone,the combination of SAS and ML385 significantly increased lipid ROS,Fe2+,and MDA while reducing GSH levels and GPX4 activity(P<0.01).SLC7A11 knockdown was successfully achieved.Compared with the NC shRNA group,SLC7A11 knockdown cells showed significantly decreased viability after SAS treatment,which was reversed by Fer-1 and DFO(P<0.01).Lipid ROS,Fe2+,and MDA content were significantly increased(P<0.01),and GSH and GPX4 were substantially decreased(P<0.05).Moreover,GPX4 protein expression was considerably reduced after SLC7A11 knockdown(P<0.01).CONCLUSION:SAS induces ferroptosis in AML cells.It promotes the nuclear translocation of NRF2 protein,which activates SLC7A11 ex-pression.Inhibition of NRF2 or downregulation of SLC7A11 sensitizes AML cells to SAS-induced ferroptosis.

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.

AIM:This study investigated the role of solute carrier family 7 member 11(SLC7A11)in sul-fasalazine(SAS)-induced ferroptosis in acute myeloid leukemia(AML)cells,focusing on the inhibitory effect of nuclear factor E2-related factor 2(NRF2)nuclear translocation-mediated activation of SLC7A11 on ferroptosis and its underlying mechanisms.METHODS:SAS-induced proliferation in AML cell lines,Kasumi-1 and THP-1,was assessed using the MTS assay.Cell death inhibitors were employed to determine the mode of cell death.Lipid reactive oxygen species(ROS)levels were measured by flow cytometry;Fe2+,malonodialdehyde(MDA),glutathione(GSH)levels,and glutathione per-oxidase 4(GPX4)activity were assessed using micromethods.Quantitative PCR(qPCR)was performed to evaluate changes in SLC7A11 mRNA during SAS-induced ferroptosis,while Western blot measured SLC7A11 and GPX4 protein levels.Moreover,Western blot assessed NRF2 nuclear translocation post-SAS treatment.The NRF2 inhibitor ML385 was used to validate these effects.SLC7A11 mRNA and protein levels were then measured following combined SAS and ML385 treatment via qPCR and Western blot.Cell viability and ferroptosis-related indices were evaluated under the same treatment conditions.Furthermore,a shRNA vector targeting SLC7A11 was constructed to assess changes in cell viability and ferroptosis markers after SLC7A11 knockdown with SAS.GPX4 protein levels were examined following SLC7A11 knockdown.RESULTS:SAS significantly inhibited the proliferation of Kasumi-1 and THP-1 cells at 200 μmol/L and 300 μmol/L,respectively(P<0.05).Only ferroptosis inhibitors(Fer-1 and DFO)significantly reversed SAS-induced cy-totoxicity(P<0.01).SAS increased lipid ROS,Fe2+,and MDA levels(P<0.01),while reducing GSH and GPX4 activity(P<0.01).The mRNA and protein expressions of SLC7A11 increased during SAS-induced ferroptosis(P<0.01),where-as GPX4 protein decreased significantly(P<0.01).SAS significantly increased the nuclear-to-cytoplasmic NRF2 ratio(P<0.01),which decreased upon co-treatment with ML385(P<0.05).Following SAS and ML385 co-treatment,both SLC7A11 mRNA and protein levels were downregulated(P<0.01).This combination treatment further reduced AML cell viability(P<0.01),an effect reversed by Fer-1 and DFO(P<0.01).Compared with SAS alone,the combination of SAS and ML385 significantly increased lipid ROS,Fe2+,and MDA while reducing GSH levels and GPX4 activity(P<0.01).SLC7A11 knockdown was successfully achieved.Compared with the NC shRNA group,SLC7A11 knockdown cells showed significantly decreased viability after SAS treatment,which was reversed by Fer-1 and DFO(P<0.01).Lipid ROS,Fe2+,and MDA content were significantly increased(P<0.01),and GSH and GPX4 were substantially decreased(P<0.05).Moreover,GPX4 protein expression was considerably reduced after SLC7A11 knockdown(P<0.01).CONCLUSION:SAS induces ferroptosis in AML cells.It promotes the nuclear translocation of NRF2 protein,which activates SLC7A11 ex-pression.Inhibition of NRF2 or downregulation of SLC7A11 sensitizes AML cells to SAS-induced ferroptosis.

OBJECTIVE To understand the distribution and drug susceptibility rates of clinical Nocardia isolates so as to provide bases for standardized clinical diagnosis and treatment.METHODS The characteristics of clinical dis-tribution of the Nocardia strains that were isolated from The Second Affiliated Hospital of Fujian Medical Univer-sity between Aug.2019 and Aug.2024 were retrospectively analyzed.The isolated strains were identified by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS),16S rRNA and rpoB gene sequencing were performed for the strains with low score,and the drug susceptibility testing was carried out by broth micro dilution method.RESULTS Totally 35 strains of Nocardia were isolated from clinical specimens in the five years,11 of which were Nocardia cyriacigeorgica,4 were Nocardia asiatica,3 were No-cardia farcinica,3 were Nocardia brasiliensis,3 were Nocardia sputorum,2 were Nocardia nova,2 were No-cardia otitidiscaviarum,2 were Nocardia beijingensis,2 were Nocardia concava,1 was Nocardia abscessus,1 was Nocardia pseudobrasiliensis,and 1 was Nocardia terpenica.Totally 85.71％of the strains were isolated from lower respiratory tract specimens including sputum,bronchoalveolar lavage fluid,bronchial brushing and lung puncture tissues,and 11.43％were isolated from skin and soft tissues.It was basically same in the male to female ratio for the patients with Nocardia infections,there were 18 cases of male and 17 cases of female.The elderly patients were dominant,and the patients aged more than 60 years old accounted for 51.43％.The strains were mainly isolated from respiratory medicine department and critical care medicine department.The drug sus-ceptibility rates of all the isolated strains to amikacin and linezolid were 100％,the drug susceptibility rates to sul-famethoxazole-trimethoprim were 97.14％,and the drug susceptibility rates to tobramycin,ceftriaxone and imi-penem were 80％,65.71％and 62.86％,respectively;the drug resistance rates to clarithromycin and ciprofloxa-cin were 65.71％and 62.86％,respectively.Among the major species of isolated Nocardia strains,the N.cyri-acigeorgica strains were all sensitive to sulfamethoxazole-trimethoprim,linezolid,tobramycin,amikacin,imipen-em and ceftriaxone,the strains were resistant to ciprofloxacin,and the drug resistance rate to clarithromycin reached up to 81.82％.CONCLUSIONS N.cyriacigeorgica is the predominant species of isolated Nocardia strains.The pulmonary infection is the major type of infection.There is little difference in the male to female ratio among the patients with Nocardia infection,and the elderly patients are dominant.Amikacin,linezolid and sulfame-thoxazole-trimethoprim are the most sensitive drugs,and the drug resistance rates of the stains to clarithromycin are high.

OBJECTIVE To understand the distribution and drug susceptibility rates of clinical Nocardia isolates so as to provide bases for standardized clinical diagnosis and treatment.METHODS The characteristics of clinical dis-tribution of the Nocardia strains that were isolated from The Second Affiliated Hospital of Fujian Medical Univer-sity between Aug.2019 and Aug.2024 were retrospectively analyzed.The isolated strains were identified by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS),16S rRNA and rpoB gene sequencing were performed for the strains with low score,and the drug susceptibility testing was carried out by broth micro dilution method.RESULTS Totally 35 strains of Nocardia were isolated from clinical specimens in the five years,11 of which were Nocardia cyriacigeorgica,4 were Nocardia asiatica,3 were No-cardia farcinica,3 were Nocardia brasiliensis,3 were Nocardia sputorum,2 were Nocardia nova,2 were No-cardia otitidiscaviarum,2 were Nocardia beijingensis,2 were Nocardia concava,1 was Nocardia abscessus,1 was Nocardia pseudobrasiliensis,and 1 was Nocardia terpenica.Totally 85.71％of the strains were isolated from lower respiratory tract specimens including sputum,bronchoalveolar lavage fluid,bronchial brushing and lung puncture tissues,and 11.43％were isolated from skin and soft tissues.It was basically same in the male to female ratio for the patients with Nocardia infections,there were 18 cases of male and 17 cases of female.The elderly patients were dominant,and the patients aged more than 60 years old accounted for 51.43％.The strains were mainly isolated from respiratory medicine department and critical care medicine department.The drug sus-ceptibility rates of all the isolated strains to amikacin and linezolid were 100％,the drug susceptibility rates to sul-famethoxazole-trimethoprim were 97.14％,and the drug susceptibility rates to tobramycin,ceftriaxone and imi-penem were 80％,65.71％and 62.86％,respectively;the drug resistance rates to clarithromycin and ciprofloxa-cin were 65.71％and 62.86％,respectively.Among the major species of isolated Nocardia strains,the N.cyri-acigeorgica strains were all sensitive to sulfamethoxazole-trimethoprim,linezolid,tobramycin,amikacin,imipen-em and ceftriaxone,the strains were resistant to ciprofloxacin,and the drug resistance rate to clarithromycin reached up to 81.82％.CONCLUSIONS N.cyriacigeorgica is the predominant species of isolated Nocardia strains.The pulmonary infection is the major type of infection.There is little difference in the male to female ratio among the patients with Nocardia infection,and the elderly patients are dominant.Amikacin,linezolid and sulfame-thoxazole-trimethoprim are the most sensitive drugs,and the drug resistance rates of the stains to clarithromycin are high.

[Objective]To evaluate the utility of left atrial(LA)volume and strain measured by 4D auto left atrial quantification(4D auto LAQ)in differentiating pre-capillary from post-capillary pulmonary hypertension(PH),and to compare its discriminative performance with echocardiographic pulmonary to left atrial global strain ratio(ePLAGS).[Methods]A total of ninety-eight subjects with intermediate to high probability of PH were prospectively enrolled.Clinical history and laboratory data were collected.All patients underwent comprehensive transthoracic echocardiography,and LA volume and strain parameters were measured by dedicated commercial software for LA 4D analysis.[Results]Based on pulmonary arterial wedge pressure,patients were divided into pre-capillary PH group[n=39;mean age(53±24)years]and post-capillary PH group[n=59;mean age(57±18)years].Compared to the pre-capillary PH group,the post-capillary PH group showed significantly higher LAVImax,LAVImin and LAVIpreA but markedly lower LASr and LAScd.Multivariate logistic regression identified LAVImax[OR:1.40;95%CI:(1.052,1.872);P=0.021]and LAScd[OR:1.76;95%CI:(1.183,2.489);P=0.004]as independent predictors of post-capillary PH.ROC analysis demonstrated that LAVImax(AUC=0.82,P＜0.001)and LAScd(AUC=0.78,P＜0.001)had strong discriminating power for predicting post-capillary PH group,with optimal cutoff values of 35.69 mL/m2(sensitivity 86%,specificity 74%)and-9%(sensitivity 80%,specificity70%).[Conclusion]LAVImax and LAScd measured with 4D auto LAQ are robust parameters for distinguishing pre-capillary PH from post-capillary PH.

[Objective]To evaluate the utility of left atrial(LA)volume and strain measured by 4D auto left atrial quantification(4D auto LAQ)in differentiating pre-capillary from post-capillary pulmonary hypertension(PH),and to compare its discriminative performance with echocardiographic pulmonary to left atrial global strain ratio(ePLAGS).[Methods]A total of ninety-eight subjects with intermediate to high probability of PH were prospectively enrolled.Clinical history and laboratory data were collected.All patients underwent comprehensive transthoracic echocardiography,and LA volume and strain parameters were measured by dedicated commercial software for LA 4D analysis.[Results]Based on pulmonary arterial wedge pressure,patients were divided into pre-capillary PH group[n=39;mean age(53±24)years]and post-capillary PH group[n=59;mean age(57±18)years].Compared to the pre-capillary PH group,the post-capillary PH group showed significantly higher LAVImax,LAVImin and LAVIpreA but markedly lower LASr and LAScd.Multivariate logistic regression identified LAVImax[OR:1.40;95%CI:(1.052,1.872);P=0.021]and LAScd[OR:1.76;95%CI:(1.183,2.489);P=0.004]as independent predictors of post-capillary PH.ROC analysis demonstrated that LAVImax(AUC=0.82,P＜0.001)and LAScd(AUC=0.78,P＜0.001)had strong discriminating power for predicting post-capillary PH group,with optimal cutoff values of 35.69 mL/m2(sensitivity 86%,specificity 74%)and-9%(sensitivity 80%,specificity70%).[Conclusion]LAVImax and LAScd measured with 4D auto LAQ are robust parameters for distinguishing pre-capillary PH from post-capillary PH.

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