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·To analyze the molecular epidemiological characteristics of Klebsiella pneumoniae isolated from children,including the distribution of serotypes,resistance genes,and virulence genes,to provide a scientific basis for the prevention and treatment strategies of Klebsiella pneumoniae infections in children.Methods·A total of 133 non-duplicate strains of Klebsiella pneumoniae clinically isolated from Shanghai Children's Hospital,Shanghai Jiao Tong University School of Medicine,from April 2023 to April 2024,were collected.Antimicrobial susceptibility testing was performed by using the Vitek-2 Compact system.Capsular polysaccharide K antigen serotypes(K types)were determined by wzy-dependent initiator(wzi)gene sequencing.Resistance genes were detected by the colloidal gold method.Virulence genes and lipopolysaccharide O antigen serotypes(O types)were identified by PCR method.Results·Among the 133 strains of Klebsiella pneumoniae,a total of 50 strains of carbapenem-resistant Klebsiella pneumoniae(CRKP)were detected,mainly distributed in the neonatal ward and intensive care unit(ICU).CRKP exhibited high resistance to most antimicrobial agents,and the main type of carbapenemase gene was blaNDM(34/50,68.00%),followed by co-carriage of blaNDM+blaOXA-48(10/50,20.00%)and blaKPC(6/50,12.00%).Serotype analysis revealed that the 50 CRKP strains could be divided into 8 K types and 6 O types.The most common K type was KL17(30/50,60.00%),followed by KL105(10/50,20.00%)and KL47(5/50,10.00%).The most common O type was O4(30/50,60.00%),followed by O3b(7/50,14.00%,),O3/O3a(6/50,12.00%),and OL101(5/50,10.00%).Significant correlations were identified between KL47 and OL101 serotypes(KL47:OL101),between KL17 and O4 serotypes(KL17:O4),and between KL1/KL2 and O1 serotypes(KL1/KL2:O1).Conclusion·The CRKP strains infecting children primarily carry blaNDM-type carbapenemase genes,showing a significant difference compared to CRKP-infected adults.The detection rate of CRKP in the neonatal ward is significantly higher than those in other departments,suggesting that infection prevention and control measures in this ward need to be strengthened.

Objective To explore the effect and mechanism of Slc1a2 overexpression on cognitive dysfunction in sleep-deprived mice.Methods A total of 130 mice were divided into five groups:normal sleep(NS),NS+ov-Slc1a2,sleep deprivation(SD),SD+ov-NC,and SD+ov-Slc1a2,with 26 mice in each group.The SD mice model was established using an automatic system based on a rotating rod,and overexpress Slc1a2 adenovirus was injected into the prefrontal cortex(PFC).Immunofluorescence and Western blotting were used to detect the expression of Slc1a2 in the mouse PFC.Electrophysiological tests were used to evaluate non-rapid eye movement(NREM)sleep time,rapid eye movement(REM)sleep time,and wakefulness time in mice.Real-time quantitative PCR was used to detect the expression of glutamate(Glu)and gamma-aminobutyric acid(GABA)metabolic enzymes in the mouse PFC.Whole-cell patch-clamp recording was used to detect the frequency and amplitude of miniature excitatory postsynaptic currents(mEPSC)in mouse PFC.Immunofluorescence was used to detect the proportion of GABA-positive cells in the mouse PFC.The C11-BODIPY fluorescent probe was used to detect lipid reac-tive oxygen species(ROS)levels in mouse PFC.Commercial kits were used to detect Fe2+and malondialdehyde(MDA)levels in the mouse PFC.Cognitive function in mice was evaluated using the open field,novel object recognition,and Y-maze tests.Results Compared with the NS group,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index increased significantly,while wakefulness time decreased significantly in the NS+ov-Slc1a2 group(all P＜0.05).The percentage of Slc1a2+GFAP+cells,expression of Slc1a2 protein,expression of Glul,Slc6a1,and Abat mRNA,frequency and amplitude of mEPSC,and proportion of GABA-positive cells in the PFC increased significantly,whereas lipid ROS,Fe2+,and MDA levels decreased significantly(all P＜0.05).Compared with the NS group,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index of the SD group and the SD+ov-NC group were significantly decreased,whereas wakefulness time was significantly increased(all P＜0.05).The percentage of Slc1a2+GFAP+cells,expression of Slc1a2 protein,expression of Glul,Slc6a1,and Abat mRNA,frequency and amplitude of mEPSC,and proportion of GABA-positive cells in the mouse PFC decreased significantly,whereas lipid ROS,Fe2+,and MDA levels increased significantly(all P＜0.05).Compared with the SD and SD+ov-NC groups,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index of the SD+ov-Slc1a2 group increased significantly,whereas the wakeful-ness time decreased significantly(all P＜0.05).The percentage of Slc1a2+GFAP+cells,the expression of Slc1a2 protein,the expression of Glul,Slc6a1,and Abat mRNA,the frequency and amplitude of mEPSC,and the proportion of GABA-positive cells in the mouse PFC increased significantly,whereas lipid ROS,Fe2+,and MDA levels decreased significantly(all P＜0.05).Conclusion Ectopic overexpres-sion of Slc1a2 in the PFC can improve sleep disorders in SD mice,reduce the damage caused by SD to excitatory synaptic transmission and GABAergic neuron function in the PFC,and alleviate cognitive impairment and anxiety-like behavior in these mice.Its mechanism may be related to the improvement of Glu/GABA metabolic imbalance in the PFC and inhibition of ferroptosis.

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 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.

Aim To elucidate whether Astragaloside Ⅳcould ameliorate pathological myocardial hypertrophy and fibrosis via the EGR1-SIRT1-PPARα-SCAD signa-ling pathway in TAC mice.Methods After randomi-zing mice into groups,the Sham+AS-Ⅳ group and TAC+AS-Ⅳ group were intragastrically administered 20 mg·kg-1AS-Ⅳ once daily,whereas the Sham+NS group and TAC+NS group were given equivalent saline.Six weeks post-surgery,an evaluation of cardiac function was conducted,heart weight index was compu-ted,morphological alterations in heart were noted,vari-ations in collagen and myocardial hypertrophy indexes were analyzed,ATP content,free fatty acid content,hydroxyproline content,SCAD expression,and enzyme activity were measured,and an initial investigation into the protein expression of EGR1-SIRT1-PPARα-SCAD in myocardial tissues was undertaken.Results After AS-Ⅳ intervention,the heart weight index of TAC mice decreased(P＜0.01),LVAWd,LVAWs,LVPWd and LVPWs values decreased(P＜0.01,P＜0.05),EF％and FS％values increased(all P＜0.01),myocardial hypertrophy markers and collagen area decreased,FFA content,HYP content and collagen expression de-creased(all P＜0.01),SCAD enzyme activity and ex-pression increased(P＜0.01,P＜0.05),and ATP content increased(P＜0.01).The expression of EGR1 protein decreased,and the expression of SIRT1 and PPARα protein increased(all P＜0.01).Conclu-sions AS-Ⅳ may improve fatty acid oxidation via the EGR1-SIRT1-PPARα-SCAD signaling pathway,thereby ameliorating pathological myocardial hypertrophy and fibrosis in TAC model mice.

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.

Objective To explore the effect and mechanism of Slc1a2 overexpression on cognitive dysfunction in sleep-deprived mice.Methods A total of 130 mice were divided into five groups:normal sleep(NS),NS+ov-Slc1a2,sleep deprivation(SD),SD+ov-NC,and SD+ov-Slc1a2,with 26 mice in each group.The SD mice model was established using an automatic system based on a rotating rod,and overexpress Slc1a2 adenovirus was injected into the prefrontal cortex(PFC).Immunofluorescence and Western blotting were used to detect the expression of Slc1a2 in the mouse PFC.Electrophysiological tests were used to evaluate non-rapid eye movement(NREM)sleep time,rapid eye movement(REM)sleep time,and wakefulness time in mice.Real-time quantitative PCR was used to detect the expression of glutamate(Glu)and gamma-aminobutyric acid(GABA)metabolic enzymes in the mouse PFC.Whole-cell patch-clamp recording was used to detect the frequency and amplitude of miniature excitatory postsynaptic currents(mEPSC)in mouse PFC.Immunofluorescence was used to detect the proportion of GABA-positive cells in the mouse PFC.The C11-BODIPY fluorescent probe was used to detect lipid reac-tive oxygen species(ROS)levels in mouse PFC.Commercial kits were used to detect Fe2+and malondialdehyde(MDA)levels in the mouse PFC.Cognitive function in mice was evaluated using the open field,novel object recognition,and Y-maze tests.Results Compared with the NS group,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index increased significantly,while wakefulness time decreased significantly in the NS+ov-Slc1a2 group(all P＜0.05).The percentage of Slc1a2+GFAP+cells,expression of Slc1a2 protein,expression of Glul,Slc6a1,and Abat mRNA,frequency and amplitude of mEPSC,and proportion of GABA-positive cells in the PFC increased significantly,whereas lipid ROS,Fe2+,and MDA levels decreased significantly(all P＜0.05).Compared with the NS group,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index of the SD group and the SD+ov-NC group were significantly decreased,whereas wakefulness time was significantly increased(all P＜0.05).The percentage of Slc1a2+GFAP+cells,expression of Slc1a2 protein,expression of Glul,Slc6a1,and Abat mRNA,frequency and amplitude of mEPSC,and proportion of GABA-positive cells in the mouse PFC decreased significantly,whereas lipid ROS,Fe2+,and MDA levels increased significantly(all P＜0.05).Compared with the SD and SD+ov-NC groups,the NREM sleep time,REM sleep time,central area stay time,recognition index,and novel wall selection index of the SD+ov-Slc1a2 group increased significantly,whereas the wakeful-ness time decreased significantly(all P＜0.05).The percentage of Slc1a2+GFAP+cells,the expression of Slc1a2 protein,the expression of Glul,Slc6a1,and Abat mRNA,the frequency and amplitude of mEPSC,and the proportion of GABA-positive cells in the mouse PFC increased significantly,whereas lipid ROS,Fe2+,and MDA levels decreased significantly(all P＜0.05).Conclusion Ectopic overexpres-sion of Slc1a2 in the PFC can improve sleep disorders in SD mice,reduce the damage caused by SD to excitatory synaptic transmission and GABAergic neuron function in the PFC,and alleviate cognitive impairment and anxiety-like behavior in these mice.Its mechanism may be related to the improvement of Glu/GABA metabolic imbalance in the PFC and inhibition of ferroptosis.