Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To 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.

Cataract extraction is often combined with the implantation of intraocular lens (IOL) with the diopter matching the operated eye to restore optimal visual function after surgery.However, there are often errors between the actual refractive power of the operated eye and the predicted value.One of the major causes of postoperative refractive error is the change in IOL position compared with the expected position.In order to improve the accuracy of postoperative refraction prediction, Holladay proposed to introduce the concept of effective lens position (ELP) into the IOL diopter calculation formula.The differences in the parameters and algorithms incorporated in the calculation of ELP lead to differences in the accuracy of IOL calculation formulas.With the application of multi-parameter calculation methods, especially the formula based on the artificial intelligence algorithm, the accuracy of IOL calculation formula has been significantly improved.ELP is also affected by various factors such as differences in ocular anatomy, IOL design and material, and surgical procedures, especially the factors affecting the stability of the capsular bag that increase the difficulty of accurately predicting ELP.Therefore, the changes in postoperative ELP need to be further discussed in order to obtain more accurate postoperative refraction.This article aimed to give a review of the development of calculation formulas and the influencing factors of ELP.

Objective To analyze the main distribution of multi-drugresistant bacteria(MDROS)from 2012 to 2016.Methods Methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Acinetobacter baumanni(CRABA),carbapenem-resistant Pseudomonas aeruginosa(CRPAE),vancomycin resistant entero-coccus(VRE),carbapenem-resistant Enterobacteriaceae bacteria(CRE)were retrospectively analyzed. Results There were 529 strains of MRSA,718 strains of CRABA,96 strains of CRPAE,4 strains of VRE,48 strains of CRE detected in five years,and most were from department of ICU,neurosurgery,respiratory,burns and paediatrics.The most MDROS were detected from sputum and excretion samples.There were 13 strains producing KPC-2,and 3 strains producing NDM-5 among 16 strains resistant to carbon penicillium strain.Con-clusion CRABA and MRSA are the main MDROS in the hospital.CRPAE,CRE and VRE are significantly lower than those in similar reports.The future work should focus on strengthening the management of various MDROS,while the timeliness and correctness of clinical specimen delivery are the prerequisite for reliable mo-nitoring data.

Objective To investigate the relationship between intracranial atherosclerotic plaque stability and stroke recurrence risk.Methods Forty-eight patients with acute ischemic stroke caused by intracranial atherosclerosis in Guangdong Province Hospital of TCM were analyzed retrospectively.After the Essen Stroke Risk Scale (ESRS) was used to assess the risk factors for the patients,they were divided into either an ESRS ≥3 group (n=21 in the high-risk recurrence group) or an ESRS <3 group (n=27 in the low-risk recurrence group).Both groups of patients underwent high-resolution MR imaging (HR-MRI) examinations of the intracranial guilty vessels (basilar artery or unilateral middle cerebral artery).According to the signal intensity of HR-MRI on the T1-weighted imaging,T2-weighted imaging,and T1 fat suppression sequences,the intracranial atherosclerotic stable plaques and unstable plaques were distinguished.The stabilization of intracranial atherosclerotic plaques was compared in patients of both groups.Results There were significant differences in the age and incidences of hypertension,diabetes mellitus,and unstable plaques in patients of both groups (P<0.05).Further multivariate logistic regression analysis of the four factors showed that the age,hypertension,diabetes,and intracranial atherosclerotic unstable plaques were the high-risk factors for recurrent ischemic stroke (ORs,87.114,159.423,8.942,and 11.551,respectively;95%CIs 4.218-1 799.078,3.235-7 855.957,1.054-75.857,and 1.011-132.043,respectively;all P<0.05).Conclusion In addition to the traditional risk factors such as age,hypertension,and diabetes,the intracranial atherosclerotic unstable plaque is an independent risk factor for high-risk recurrence of ischemic stroke.

Objective: To establish a hydrogen peroxide (H₂O₂) induced injury model of pulmonary artery endothelial cells (PAECs) and explore the molecular mechanisms of oxidative stress on the structure and function of PAECs in this model. Methods: Human PAECs were treated with H₂O₂ at different concentrations (25, 50, 100, 200, 400, 800, 1 600, 3 200, 6 400 μmol/L) for 4 and 24 h, respectively. The PAECs survival curve was obtained according to the cell viability measured by CCK-8 assay. The cell apoptosis of PAECs was detected by flow cytometry. The reactive oxygen species (ROS) generation and mitochondrial activity were measured using small molecule fluorescent probes. Proteins were extracted and the phosphorylation levels of signal molecules in PAECs were detected by Western blot assays. Results: (1) The effect of H₂O₂ at various concentrations on cell viability of PAECs: cell viability of PAECs decreased in proportion to increasing concentration of H₂O₂ after incubation for 4 h. The half maximal inhibitory concentration (IC₅₀) of PAECs exposed to H₂O₂ for 4 and 24 h were 397.00 and 488.77 μmol/L, respectively. (2) The effect of H₂O₂ on cell apoptosis of PAECs: After H₂O₂ incubation for 4 h, proportions of PAECs at late-apoptosis ((22.58±3.69) %) and necrotic stage( (11.86±4.27)%) were significantly higher than those of control PAECs at late-apoptosis stage( (3.41±1.44)%, P<0.01) and at necrotic stage ((1.94±1.15) % , P<0.05). The survival rate of PAECs post H₂O₂ was dramatically lower than that of control PAECs ((7.98±3.21)% vs. (48.89±8.08)%, P<0.01). However, there is no statistical difference between both groups regarding to the early apoptosis. (3) The effect of H₂O₂ on mitochondrial activity and ROS production of PAECs: the mitochondrial activity and ROS generation of PAECs treated by H₂O₂ were significantly increased compared to those in control PAECs (P<0.01). (4) The effect of H₂O₂ on signaling molecules in PAECs: there was a significant increase in phosphorylation level of Akt in PAECs incubated with H₂O₂ for 30 minutes compared to that in control PAECs (P<0.01), while there was no significant difference in levels of Akt between H₂O₂ treated PAECs and control PAECs. Phosphorylation level of JNK as well as p38 were also significantly upregulated in H₂O₂ treated PAECs (P<0.01). Conclusion H₂O₂ at the concentration of 400 μmol/L could induce human PAECs injuries via the regulation of Akt and MAPK signaling pathways.