Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective To summarize the changing prevalence of carbapenem resistance in Enterobacterales based on the data of CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021 for improving antimicrobial treatment in clinical practice.Methods Antimicrobial susceptibility testing was performed using a commercial automated susceptibility testing system according to the unified CHINET protocol.The results were interpreted according to the breakpoints of the Clinical & Laboratory Standards Institute(CLSI)M100 31st ed in 2021.Results Over the seven-year period(2015-2021),the overall prevalence of carbapenem-resistant Enterobacterales(CRE)was 9.43％(62 342/661 235).The prevalence of CRE strains in Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae was 22.38％,9.73％,and 8.47％,respectively.The prevalence of CRE strains in Escherichia coli was 1.99％.A few CRE strains were also identified in Salmonella and Shigella.The CRE strains were mainly isolated from respiratory specimens(44.23±2.80)％,followed by blood(20.88±3.40)％and urine(18.40±3.45)％.Intensive care units(ICUs)were the major source of the CRE strains(27.43±5.20)％.CRE strains were resistant to all the β-lactam antibiotics tested and most non-β-lactam antimicrobial agents.The CRE strains were relatively susceptible to tigecycline and polymyxins with low resistance rates.Conclusions The prevalence of CRE strains was increasing from 2015 to 2021.CRE strains were highly resistant to most of the antibacterial drugs used in clinical practice.Clinicians should prescribe antimicrobial agents rationally.Hospitals should strengthen antibiotic stewardship in key clinical settings such as ICUs,and take effective infection control measures to curb CRE outbreak and epidemic in hospitals.

Objective To characterize the changing species distribution and antibiotic resistance profiles of respiratory isolates in hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Commercial automated antimicrobial susceptibility testing systems and disk diffusion method were used to test the susceptibility of respiratory bacterial isolates to antimicrobial agents following the standardized technical protocol established by the CHINET program.Results A total of 589 746 respiratory isolates were collected from 2015 to 2021.Overall,82.6％of the isolates were Gram-negative bacteria and 17.4％were Gram-positive bacteria.The bacterial isolates from outpatients and inpatients accounted for(6.0±0.9)％and(94.0±0.1)％,respectively.The top microorganisms were Klebsiella spp.,Acinetobacter spp.,Pseudomonas aeruginosa,Staphylococcus aureus,Haemophilus spp.,Stenotrophomonas maltophilia,Escherichia coli,and Streptococcus pneumoniae.Each microorganism was isolated from significantly more males than from females(P＜0.05).The overall prevalence of methicillin-resistant S.aureus(MRSA)was 39.9％.The prevalence of penicillin-resistant S.pneumoniae was 1.4％.The prevalence of extended-spectrum β-lactamase(ESBL)-producing E.coli and K.pneumoniae was 67.8％and 41.3％,respectively.The overall prevalence of carbapenem-resistant E.coli,K.pneumoniae,Enterobacter cloacae,Pseudomonas aeruginosa,and Acinetobacter baumannii was 3.7％,20.8％,9.4％,29.8％,and 73.3％,respectively.The prevalence of β-lactamase was 96.1％in Moraxella catarrhalis and 60.0％in Haemophilus influenzae.The H.influenzae isolates from children(＜18 years)showed significantly higher resistance rates to β-lactam antibiotics than the isolates from adults(P＜0.05).Conclusions Gram-negative bacteria are still predominant in respiratory isolates associated with serious antibiotic resistance.Antimicrobial resistance surveillance should be strengthened in clinical practice to support accurate etiological diagnosis and appropriate antimicrobial therapy based on antimicrobial susceptibility testing results.

The receptor-binding region(RBD)of the spike protein(S)on the surface of porcine epi-demic diarrhea virus(PEDV)is a critical structural domain mediating viral invasion of host cells and serves as a key target for inducing neutralizing antibodies.In order to prepare antibodies that can be used to study the biological function of PEDV RBD and develop novel diagnostic and thera-peutic methods,recombinant RBD protein expressed in Sf9 insect cells was utilized as an immuno-gen to immunize BALB/c mice.Monoclonal antibodies(mAbs)were generated via hybridoma tech-nology,and positive hybridoma clones were screened using indirect ELISA.The reactivity of the mAbs was subsequently characterized.The results of ELISA,Western blot,and indirect immuno-fluorescence assay(IFA)showed that three monoclonal antibodies screened(3E5,4F9 and 5A5)had good reactivity with the virus and RBD protein.Antibody subtype results showed that 3E5 and 4F9 were of IgG1 subtypes and 5A5 was of IgM subtype.Neutralization assay further revealed that 3E5 monoclonal antibody had viral neutralizing activity.In this study,three monoclonal antibodies against PEDV RBD proteins were successfully prepared,providing the basis for the study of the bi-ological function of RBD proteins,PEDV serologic detection and vaccine development.

ObjectiveTo investigate the effects of the combination of components from Tripterygii Radix et Rhizoma and Chuanxiong Rhizoma on rheumatoid arthritis fibroblast-like synoviocytes （RA-FLSs） and the underlying mechanism. MethodsRA-FLSs were grouped as follows： blank control， positive control （methotrexate）， Tripterygii Radix et Rhizoma components， Chuanxiong Rhizoma components， and components from Tripterygii Radix et Rhizoma+Chuanxiong Rhizoma. The cell-counting kit-8 （CCK-8） assay was employed to the cell proliferation， invasion， and apoptosis. The levels of tumor necrosis factor （TNF）-α， interleukin （IL）-6， reactive oxygen species （ROS）， and malondiadehyde （MDA） in cells were measured. Western blot was employed to determine the protein levels of nuclear factor erythroid 2-related factor 2 （Nrf2）， heme oxygenase-1 （HO-1）， nuclear factor-kappa B （NF-κB） p65， phosphorylated inhibitory subunit of NF-κBα （p-IκBα）， cysteinyl aspartate-specific protease-3 （Caspase-3）， and B-cell lymphoma 2 （Bcl-2）. Real-time PCR was employed to determine the mRNA levels of Nrf2， HO-1， and NF-κB p65. ResultsThe cells in the groups of positive control， Tripterygii Radix et Rhizoma components， Chuanxiong Rhizoma components， and components from Tripterygii Radix et Rhizoma+Chuanxiong Rhizoma were treated with 2.50 mg·L^-1 methotrexate， 0.20 mg·L^-1 triptolide + 0.20 mg·L^-1 celastrol， 5.00 mg·L^-1 ferulic acid + 20.00 mg·L^-1 ligustrazine， 0.20 mg·L^-1 triptolide + 0.20 mg·L^-1 celastrol + 5.00 mg·L^-1 ferulic acid + 20.00 mg·L^-1 ligustrazine， respectively. Compared with the blank control group， drug administration reduced the proliferation and invasion and increased the apoptosis of cells （P<0.01）， lowered the levels of TNF-α， IL-6， ROS， and MDA （P<0.01）， up-regulated the mRNA and protein levels of Caspase-3， Nrf2， and HO-1 （P<0.01）， and down-regulated the mRNA and protein levels of Bcl-2， NF-κB p65， and p-IκBα （P<0.01）. Compared with the Tripterygii Radix et Rhizoma components group， the combination of components from Tripterygii Radix et Rhizoma+Chuanxiong Rhizoma inhibited the proliferation and invasion （P<0.05） and promoted the apoptosis of RA-FLSs， up-regulated the mRNA levels of Nrf2 and HO-1 and protein levels of Nrf2 and Caspase-3 （P<0.05）， and down-regulated the protein levels of NF-κB p65 and p-IκBα （P<0.05）. ConclusionThe combination of components from Chuanxiong Rhizoma and Tripterygii Radix et Rhizoma can inhibit the proliferation and invasion and promote the apoptosis of RA-FLSs and alleviate oxidative stress and inflammation by inhibiting the NF-κB signaling pathway， activating the Nrf2/HO-1 pathway， and regulating the expression of Bcl-2/Caspase-3.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Objective To investigate the applicability of D-dimer levels combined with the Tei index in assessing the volume load in patients with acute decompensated heart failure(ADHF).Methods Two hundred patients admitted to the Emergency Department of Taizhou TCM Hospital between 2022 and 2023 were selected as the subjects,who were divided into a low volume load group(n=121)and a high volume load group(n=79)based on plasma volume indices.The clinical indicators and parameters of cardiac function of these subjects were compared.Multivariate Logistic regression analysis was used for identification of potential risk factors for elevated volume loads.A model for prediction of elevated volume loads was developed via Chi-square automatic interaction detection,followed by internal validation via Bootstrapping.Logistic regression analysis was used to study the interactions between D-dimer levels and Tei indices in assessing the volume loads of patients with ADHF.Results Multivariate regression analysis showed that age,Tei index,D-dimer levels and B type natriuretic peptide(BNP)were risk factors for high volume loads in ADHF patients.The decision tree model established had 14 nodes and 8 terminal nodes.Four explanatory variables including age,Tei index,D-dimer levels and BNP were screened out.The area under curve(AUC),sensitivity,specificity and prediction accuracy of the classification tree model were higher than those of the regression model.When D-dimer levels ≥1.16 and Tei index ≥0.65 interacted and co-existed,ADHF patients were at higher risk of developing high volume loads(OR=6.526,95％CI:2.439-7.183).The results of restricted cubic spline analysis pointed to nonlinear dose response relationships in the correlation strength of D-dimer levels,Tei index and volume loads.Conclusion There are interactions between D-dimer levels and Tei index,and the risk of high volume loads in ADHF patients is significantly increased when D-dimer levels are 1.16 or above and Tei index is 0.65 or above.

In this paper, the technical basis and latest progress of X-ray tube for CT systems are introduced, with emphasis on material innovation, superconducting technology, liquid metal bearing, low dose scanning and electron beam filtration. As the core component of CT equipment, the technological innovation of CT X-ray tubes significantly improves image quality, reduces radiation dose, improves efficiency, and extends the service life of the X-ray tubes. Domestic and foreign manufacturers have made remarkable progress in the field of CT X-ray tubes. Domestic manufacturers, such as the 12th Institute of CLP, have made important progress in the development of CT X-ray tubes, and successfully achieved independent research and development of high-end CT X-ray tubes. Foreign manufacturers such as Siemens, GE, Philips and other manufacturers continue to innovate in liquid metal bearings, superconducting technology, new targets and other aspects to maintain technology leadership. In the future, CT X-ray tubes will develop in the direction of personalization, intelligence, long life, miniaturization and portability, providing more accurate and low-risk technical support for medical image diagnosis.
Tomography, X-Ray Computed/instrumentation* ; Equipment Design