OBJECTIVE T o assess the in vitro antimicrobial activity of aztreonam-avibactam against metallo-β—lacta-mase(MBL)-producing carbapenem-resistant Enterobacteriaceae(CRE)using different antimicrobial susceptibility testing methods,evaluate the consistency of results based on the latest breakpoints recommended by European Committee on Antimicrobial Susceptibility Testing(EUCAST),and analyze the clinical applicability.METHODS The imipenem-or meropenem-resistant Enterobacteriaceae strains were isolated from the clinical specimens of Bei-jing Chaoyang Hospital from Jan.2019 to Mar.2023,MBL-producing CRE were selected after they were con-firmed by colloidal gold immunoassay and Sanger sequencing as the study subjects.The minimum inhibitory con-centrations(MICs)of single aztreonam and aztreonam-avibactam compounds were determined by using broth mi-crodilution method.In addition,the disk diffusion method and the gradient diffusion method were employed to further detect the in vitro susceptibility to aztreonam-avibactam.RESULTS Among the 87 strains of MBL-producing CRE that were included in the study,Escherichia coli was the most common species,accounting for 44.83％.NDM-5 was the predominant carbapenemase type,detected in 48.28％of the isolates.According to the latest EUCAST break-points,6 isolates were aztreonam-avibactam-resistant strains based on broth microdilution method,all of which were E.coli,and the resistance rate was 6.90％(6/87).However,the resistance rate that was determined by the disk diffu-sion method was significantly higher(22.99％,20/87).Among these,14 strains was within the area of technical uncer-tainty/resistant,making result interpretation difficult.In addition,the categorical agreement between the gradient diffu-sion method and the broth microdilution method reached up to 98.85％.CONCLUSIONS Aztreonam-avibactam has high antimicrobial activity against MBL-producing CRE.However,based on the latest EUCAST breakpoints,the antimicrobial susceptibility testing by the disk diffusion method results of some strains are hard to interpret.It is necessary to integrate with other methods for further validation.

OBJECTIVE T o assess the in vitro antimicrobial activity of aztreonam-avibactam against metallo-β—lacta-mase(MBL)-producing carbapenem-resistant Enterobacteriaceae(CRE)using different antimicrobial susceptibility testing methods,evaluate the consistency of results based on the latest breakpoints recommended by European Committee on Antimicrobial Susceptibility Testing(EUCAST),and analyze the clinical applicability.METHODS The imipenem-or meropenem-resistant Enterobacteriaceae strains were isolated from the clinical specimens of Bei-jing Chaoyang Hospital from Jan.2019 to Mar.2023,MBL-producing CRE were selected after they were con-firmed by colloidal gold immunoassay and Sanger sequencing as the study subjects.The minimum inhibitory con-centrations(MICs)of single aztreonam and aztreonam-avibactam compounds were determined by using broth mi-crodilution method.In addition,the disk diffusion method and the gradient diffusion method were employed to further detect the in vitro susceptibility to aztreonam-avibactam.RESULTS Among the 87 strains of MBL-producing CRE that were included in the study,Escherichia coli was the most common species,accounting for 44.83％.NDM-5 was the predominant carbapenemase type,detected in 48.28％of the isolates.According to the latest EUCAST break-points,6 isolates were aztreonam-avibactam-resistant strains based on broth microdilution method,all of which were E.coli,and the resistance rate was 6.90％(6/87).However,the resistance rate that was determined by the disk diffu-sion method was significantly higher(22.99％,20/87).Among these,14 strains was within the area of technical uncer-tainty/resistant,making result interpretation difficult.In addition,the categorical agreement between the gradient diffu-sion method and the broth microdilution method reached up to 98.85％.CONCLUSIONS Aztreonam-avibactam has high antimicrobial activity against MBL-producing CRE.However,based on the latest EUCAST breakpoints,the antimicrobial susceptibility testing by the disk diffusion method results of some strains are hard to interpret.It is necessary to integrate with other methods for further validation.

Objective To determine the feasibility of neck vessel wall imaging technology with three?dimensional variable?flip?angle turbo spin?echo (3D T1w?SPACE) for the detection of carotid atherosclerotic disease before revascularization. Methods Thirty?one patients who underwent carotid endarterectomy (CEA) and fifty?three patients who underwent carotid stenting (CAS) were enrolled prospectively. Neck vessel wall imaging examination were performed in all patients whilecarotid artery DSA were performed in all CAS patients. Quantitative measurements including stenosis, lesion length, and the presence or absence of plaque ulceration obtained with 3D T1w?SPACE and DSA were independently determined. And images of the 3D T1w?SPACE were compared with corresponding histology to identify major plaque components including intraplaque hemorrhage (IPH), lipid rich necrotic core (LRNC), and calcification (CA). The consistency rate, sensitivity, specificity, positive predictive value and negative predictive value were used to assess diagnostic value. Bland?Altman plots, intraclass correlation coefficient (ICC), and Cohen Kappa were determined. Results DSA was served as the reference standard. There was an excellent correlation between 3D T1w?SPACE and DSA images in measuring stenosis (r=0.984, P<0.01) and luminal stenosis [ICC=0.98 (95% confidence interval: 0.96-0.99)]. Bland?Altman plots showed that the two examinations were in good consistency in evaluating the extent of stenosis. Sensitivity (89.5%) and specificity (95.1%) was high in 3D T1w?SPACE images compared to DSA for the detection of ulcers. The consistency rate between 3D T1w?SPACE images and histological results for IPH, LRNC and CA detection were 85.7%, 82.1% and 92.9%, respectively. Sensitivity and specificity were 90.0% and 75.0% for IPH;83.3% and 80.0% for LRNC; 91.3% and 100.0% for CA respectively. However, lesion length measurements by using 3D T1w?SPACE were longer than those measured by using DSA (P<0.01).Conclusion Neck vessel wall imaging technology with 3D T1w?SPACE is a noninvasive and accurate technique for the diagnosis of carotid artery atherosclerotic disease before revascularization.

Objective To investigate the expression of IL-17-producing regulatory T cells ( Treg) in patients with systemic lupus erythematosus ( SLE) and to analyze their clinical significance. Methods This study recruited 32 patients with SLE ( including 14 with active SLE and 18 with inactive SLE) and 13 healthy subjects matched for age and sex. Flow cytometry was performed to detect the expression of Foxp3 and IL-17 in CD4 T lymphocytes and the phenotypic characteristics of IL-17-producing Treg. Correlations between these cells and clinical indicators of SLE were analyzed. Peripheral CD4+CD25+ T cells were isola-ted from five healthy subjects and then stimulated with IL-6 and IL-1βalone or in combination. An in vitro T cell polarization assay was performed to investigate the role of cytokines in the polarization and regulation of IL-17-producing Treg. Results Compared with the healthy subjects and patients with inactive SLE, the pa-tients with active SLE had a higher percentage of IL-17-producing Treg in peripheral blood. Moreover, the expression of Foxp3 and CD45RA by IL-17-producing Treg in the active SLE group was down-regulated, while that of IL-2, granzyme B (GramB), programmed cell death protein 1 (PD-1) and glucocorticoid-in-duced tumor necrosis factor receptor ( GITR) was up-regulated. Inflammatory cytokines such as IL-6 and IL-1 could induce Treg to produce IL-17. Conclusions This study suggested that increased inflammatory cytokines might correlate with higher percentages of IL-17-producing Treg in patients with active SLE. These cells were a subset of pathogenic Treg failing to prevent autoimmune.

Endothelin (ET) is an endothelium-derived vasoconstrictive peptide. We have developed a sensitive and selective radioimmunoassay for porcine/human endothelin (ET-1). 126I-labled ET was perpared by lodogen method and was purified by HPLC. Its specific activity was about 64.75 TBq(1750Ci)/mmol. The assay has a detection limit of 0.17pg/tube and the assay range was 0.25-1000pg/tube. The procedure was developed for extraction of endothelin from human plasma using C18 Sep-pak extraction cartridges. Human plasma samples were extracted, assayed and the plasma ET values of 17 healthly volunteers was found to be 2.81 ?0.60pg/ml. Both patients with uraemia(n = 20) and acute myocardial infarction(n= 11) had significantly higher plasma values than normal subjects.