Objective To analyze the genetic characteristics and variations of influenza A (H3N2) viruses in Ma'anshan from 2022 to 2024, and to provide a scientific basis for local influenza prevention and control. Methods From April 2022 to March 2024, influenza-like illness (ILI) specimens were collected from three national influenza surveillance sentinel hospitals in Ma’anshan. Samples positive for influenza by real-time PCR were subjected to virus culture and identification. A total of 40 representative A/H3N2 strains with hemagglutination titers ≥8 were selected for whole-genome sequencing. Genetic evolution, homology, amino acid variations, and glycosylation sites were analyzed. Results All H3N2 representative strains from the 2022–2023 influenza season belonged to clade 3C.2a1b.2a.1a.1, while those from the 2023–2024 season fell into clade 3C.2a1b.2a.2a.3a.1. The nucleotide and amino acid sequence similarities of HA and NA between the 40 representative strains and the vaccine strain A/Darwin/6/2021 were all above 97.35%. Compared with the vaccine strain, amino acid mutations were identified in antigenic sites A, B, C, and E, as well as in receptor-binding sites of the HA protein. An I222V substitution was detected in the NA protein. The HA protein contained four additional glycosylation sites compared to the vaccine strain, while the glycosylation pattern of the NA protein remained consistent. Conclusion No antigenic drift was observed in the influenza A/H3N2 viruses in Ma'anshan City from 2022 to 2024, but genetic changes such as branching variations, key amino acid substitutions, and an increase in HA glycosylation sites were observed. These findings underscore the importance of sustained molecular surveillance of local influenza viruses.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.

In order to establish a highly efficient,convenient,and effective circular RNA(circRNA)vaccine preparation system,enhanced green fluorescent protein(EGFP)circRNA was constructed using permuted intron exon(PIE)strategy based on type Ⅰ introns.Then,circRNA circularization rates of RNA after in vitro transcription(IVT),primary circularization(IVC1),and secondary circularization(IVC2)were compared after purification.The constructed circRNA system was fur-ther applied to porcine reproductive and respiratory syndrome virus(PRRSV),and two circRNAs based on PRRSV GP5 protein were constructed and developed for in vitro expression.Results showed that circularization rates and protein expression effects of EGFP circRNA in IVC1 RNA and IVC2 RNA were similar,but both were significantly better than those of IVT RNA.Purity of EGFP circRNA reached 74％,and purities of two PRRSV GP5 protein circRNAs constructed using this preparation system were 71％and 64％,respectively.Western blot and indirect immunofluo-rescence assay(IFA)results indicated that both of the PRRSV GP5 protein circRNAs were suc-cessfully expressed.The results demonstrated that an easy-to-operate,low-cost circRNA prepara-tion system with high circularization rate was successfully constructed.Two PRRSV GP5 protein circRNA vaccines were successfully prepared using this system and expressed efficiently,which provides a reference for the development of animal circRNA vaccines and novel candidate vaccines against PRRSV.

The integration of science and education is not only an important strategy for promoting social progress and technological development,but also a modern form of higher education aiming at cultivating innovative talents.Conducting scientific research training for undergraduate medical students is one of the important ways to cultivate their innovative abilities and comprehensive qualities.Our team proposed a"teaching,science,and ideology trinity"teaching model to comprehensively cultivate students' scientific research comprehensive abilities under the value orientation of ideological and political education by or-ganically integrating molecular biology experimental teaching with the scientific research training of under-graduate medical students.In this teaching activity,taking the experiment of gene polymorphism as an example,our team selected students with research potential from the whole grade and divided them into 4 project groups that were instructed by 4 teachers.The students were trained in the whole process of scien-tific research,including topic selection,project writing,experimental designing,application for research ethics,and project summary.Our team has always adhered to student-contentedness of educational con-cepts to stimulate students' intrinsic motivation throughout the teaching process.Students are the design-ers and implementers of the project,and teachers are only guides and promoters of learning.After this training,students not only became familiar with the writing and implementation of scientific research pro-jects,but also improved their literature reading,experimental designing,experimental skills,and prob-lem-solving abilities.More importantly,this teaching activity also cultivated students' awareness of re-search ethics and academic moral standards.

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 investigate the changes of nitric oxide(NO),endothelin-1(ET-1),thromboxane B2(TXB2)levels in patients with chronic heart failure(CHF)and their correlation with plasma brain natriuretic peptide(BNP).Methods:We enrolled 110 CHF patients admitted in the Second Hospital of Qinhuangdao between January and December 2022.According to the New York Heart Association(NYHA)cardiac function classification,the patients were divided into cardiac function class Ⅱ group(n=22),cardiac function class Ⅲ group(n=50),and cardiac function class Ⅳ group(n=38).Baseline data,levels of NO,ET-1,TXB2,BNP and other related laboratory indexes were compared among three groups.Pearson correlation analysis was used to analyze the association of NO,ET-1,TXB2 with plasma BNP in CHF patients.Multivariate linear regression was employed to analyze related factors of elevated BNP in CHF patients.Results:Compared with patients in class Ⅱ group and class Ⅲ group,those in class Ⅳ group had significant higher uric acid[(467.39±32.60)μmol/L vs.(367.25±22.39)μmol/L vs.(421.42±28.34)μmol/L],total bilirubin[(17.36±3.10)μmol/L vs.(10.65±1.39)μmol/L vs.(11.12±2.01)μmol/L],BNP[(897.60±50.11)ng/L vs.(381.37±31.25)ng/L vs.(527.60±47.84)ng/L],NO[(50.12±5.95)μmol/L vs.(25.36±2.14)μmol/L vs.(37.92±4.84)μmol/L],ET-1[(114.10±10.53)pg/L vs.(80.25±7.38)pg/L vs.(97.03±8.40)pg/L],TXB2[(417.98±29.35)pg/ml vs.(302.63±19.63)pg/ml vs.(381.29±26.44)pg/ml](P＜0.001 all).Compared with those in class Ⅱ group,those in class Ⅲ group had significant higher above-mentioned indexes(except total bilirubin)(P＜0.001 all).Pearson correlation analysis indicated that plasma NO,ET-1,TXB2 were positively associated with BNP(r=0.828,0.750,0.720,P＜0.001 all).Multivariate linear regression analysis indicated that uric acid,total bilirubin,plasma NO,ET-1 and TXB2 levels were independent risk factors for elevated BNP level in CHF patients(B=0.555～20.550,P＜0.05 or＜0.01),while the use of angiotensin converting enzyme inhibitors(ACEI)/angiotensin Ⅱ receptor blockers(ARB)was an independent protective factor(B=-46.222,P=0.027).Conclusion:The levels of NO,ET-1,and TXB2 are closely related to the occurrence and development of CHF,and they show an increasing trend with the progression of CHF,and is closely related to BNP.

Objective To explore the correlation of bilateral knee joint strength asymmetry with balance,walking ability,and motor function in hemiplegic stroke patients,providing a reference for clinical assessment of stroke patients.Methods A total of 46 hemiplegic stroke patients admitted to the Rehabilitation Medicine Department of People's Hospital of Shijiazhuang from February to December 2023 were selected.According to the Berg Balance Scale(BBS)scores,patients were divided into Group A(BBS score≤20,n=23)and Group B(BBS score>20,n=23).The peak torque and differences of bilateral knee flexors and extensors were compared between two groups.Isokinetic technology was used to assess the differences in peak torque of bilateral knee joints at 60°/s and 120°/s.BBS,Functional Ambulation Classification(FAC),and Fugl-Meyer Assessment of Lower Extremity(FMA-LE)were used to evaluate patients'balance,walking ability,and lower limb motor function.The correlation between bilateral knee joint peak torque and its difference with the scores of three functional scales was analyzed.Results The peak torque of knee flexors and extensors at 60°/s in group A was significantly lower than that in group B(P<0.05).At both 60°/s and 120°/s the differences in peak torque between the healthy and affected sides of knee flexors and extensors were greater than those in group B(P<0.05).At 60°/s,the difference in peak torque of bilateral knee extensors in hemiplegic stroke patients was negatively correlated with the scores of BBS,FAC,and FMA-LE(r=-0.569,-0.582,-0.606,P<0.01),as did the knee flexors(r=-0.534,-0.386,-0.458,P<0.05).At 120°/s,similar negative correlations were observed for both knee extensors(r=-0.304,-0.304,-0.443,P<0.05)and flexors(r=-0.337,-0.349,-0.370,P<0.05).Conclusions Bilateral knee joint strength asymmetry in hemiplegic stroke patients is negatively correlated with balance and walking ability.The difference in strength between the two sides of knee joint may be one of the clinical indicators for evaluating the motor function of stroke patients.

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.