Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:To investigate the clinicopathological and molecular genetic features of high-grade astrocytomas with piloid features (HGAP).Methods:Clinical, histopathological and imaging data of 7 cases of HGAP diagnosed at the Neuropathology Center of Beijing Tiantan Hospital, Beijing, China from August 2023 to October 2024 were collected. The histopathological and molecular features for each case were analyzed.Results:Among the seven patients there were 4 males and 3 females, with the median age of 37 (34, 51) years. Patients exhibited various clinical symptoms and signs depending on the tumor′s location. Four tumors were located in the cerebellum, 2 in the supratentorial region, and 1 in the spinal cord. Magnetic resonance imaging showed that 6 of the 7 patients had cystic and solid lesions, with focal or nodular enhancement and relatively unclear boundaries. Histopathological features had a diverse morphological spectrum and extensive grading. Five cases displayed a pilocytic astrocytoma-like appearance with infiltrative growth patterns, while two cases presented glioblastoma-like morphology, containing locally anaplastic pleomorphic xanthoastrocytoma with minor pilocytic components. All tumors were diffusely positive for GFAP and Olig2, while 4 tumors exhibited partial or complete loss of ATRX. The Ki-67 proliferation index ranged from 2% to 40%. Next-generation sequencing showed that tumor cells most commonly harbored MAPK pathway gene mutations, and/or homozygous deletions of CDKN2A/B, and/or ATRX mutations. Among the 7 HGAP models, 3 cases showed the three types of molecular genetic variations, 1 case showed MAPK mutations and homozygous deletions of CDKN2A/B, 1 case had MAPK mutations and ATRX mutations, 1 case had only MAPK mutations, and 1 case showed no detectable molecular changes. DNA methylation clustering analyses showed that the median model prediction score was 0.94 (range, 0.85-0.99) for the 7 HGAP models. Five cases showed the MGMT promoter hypermethylation. Four patients received radiotherapy and concomitant temozolomide treatment after surgery, while three patients received no known treatments. At the last follow-up, seven patients were alive without any tumor, two patients had recurrence, and one patient was alive with the tumor.Conclusions:HGAP is relatively rare and predominantly occurs in adults. It has a wide histopathological spectrum and various histological grades, characterized by piloid astrocytoma-like and glioblastoma-like histological features. Its diagnosis relies on methylation clustering analysis. Most tumors harbor gene alterations in the MAPK signaling pathway, along with homozygous deletions of CDKN2A/B or ATRX mutations. The biological behavior is typically aggressive, while imaging and histological findings can be misleading. Therefore, clinicians need to increase their diagnostic awareness of this tumor and prevent missed diagnoses.

Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:To investigate the clinicopathological and molecular genetic features of high-grade astrocytomas with piloid features (HGAP).Methods:Clinical, histopathological and imaging data of 7 cases of HGAP diagnosed at the Neuropathology Center of Beijing Tiantan Hospital, Beijing, China from August 2023 to October 2024 were collected. The histopathological and molecular features for each case were analyzed.Results:Among the seven patients there were 4 males and 3 females, with the median age of 37 (34, 51) years. Patients exhibited various clinical symptoms and signs depending on the tumor′s location. Four tumors were located in the cerebellum, 2 in the supratentorial region, and 1 in the spinal cord. Magnetic resonance imaging showed that 6 of the 7 patients had cystic and solid lesions, with focal or nodular enhancement and relatively unclear boundaries. Histopathological features had a diverse morphological spectrum and extensive grading. Five cases displayed a pilocytic astrocytoma-like appearance with infiltrative growth patterns, while two cases presented glioblastoma-like morphology, containing locally anaplastic pleomorphic xanthoastrocytoma with minor pilocytic components. All tumors were diffusely positive for GFAP and Olig2, while 4 tumors exhibited partial or complete loss of ATRX. The Ki-67 proliferation index ranged from 2% to 40%. Next-generation sequencing showed that tumor cells most commonly harbored MAPK pathway gene mutations, and/or homozygous deletions of CDKN2A/B, and/or ATRX mutations. Among the 7 HGAP models, 3 cases showed the three types of molecular genetic variations, 1 case showed MAPK mutations and homozygous deletions of CDKN2A/B, 1 case had MAPK mutations and ATRX mutations, 1 case had only MAPK mutations, and 1 case showed no detectable molecular changes. DNA methylation clustering analyses showed that the median model prediction score was 0.94 (range, 0.85-0.99) for the 7 HGAP models. Five cases showed the MGMT promoter hypermethylation. Four patients received radiotherapy and concomitant temozolomide treatment after surgery, while three patients received no known treatments. At the last follow-up, seven patients were alive without any tumor, two patients had recurrence, and one patient was alive with the tumor.Conclusions:HGAP is relatively rare and predominantly occurs in adults. It has a wide histopathological spectrum and various histological grades, characterized by piloid astrocytoma-like and glioblastoma-like histological features. Its diagnosis relies on methylation clustering analysis. Most tumors harbor gene alterations in the MAPK signaling pathway, along with homozygous deletions of CDKN2A/B or ATRX mutations. The biological behavior is typically aggressive, while imaging and histological findings can be misleading. Therefore, clinicians need to increase their diagnostic awareness of this tumor and prevent missed diagnoses.

ObjectiveTo investigate the role and mechanism of hyodeoxycholic acid （HDCA） in the progression of metabolic associated fatty liver disease （MAFLD）， and to provide a new theoretical basis for further clarifying the pathogenesis of MAFLD. MethodsL02 hepatocytes were used as experimental cells， and palmitic acid was used to induce steatosis in L02 cells. The farnesoid X receptor （FXR） siRNA interference chain technique was used to construct a hepatocyte cell line with low FXR expression. CCK8 assay was used to observe the effect of HDCA on L02 steatosis hepatocytes at different concentrations （0， 100， 200， 300， and 400 μmol/L） and time points （12， 24， 36， and 48 hours）. The method of qRT-PCR was used to measure the mRNA expression levels of FXR， proliferating cell nuclear antigen （PCNA）， Cyclin D1， phosphatidylinositol 3-kinase （PI3K）， and protein kinase-B （AKT）， and Western blot was used to measure the protein expression levels of FXR， Cyclin D1， PCNA， PI3K， phosphorylated PI3K （p-PI3K）， AKT， and phosphorylated （p-AKT）. A one-way analysis of variance was used for comparison of normally distributed continuous data with homogeneity of variance between multiple groups， and the Tukey HSD test was used for further comparison between two groups； the Welch analysis of variance was used for comparison of normally distributed continuous data with heterogeneity of variance between multiple groups， and the Games-Howell test was used for further comparison between two groups. The independent-samples t test was used for comparison between two groups. ResultsCCK8 assay showed a significant reduction in the viability of L02 cells and steatosis hepatocytes treated by 300 μmol/L HDCA （P<0.05）， and qRT-PCR showed a significant increase in the mRNA expression level of FXR and significant reductions in the mRNA expression levels of PCNA， Cyclin D1， PI3K， and AKT （all P<0.05）. Western blot showed a significant increase in the protein expression level of FRX （P<0.05）， and after interference of FXR expression in L02 cells， there were significant increases in the protein expression levels of PCNA， PI3K， p-PI3K， AKT， and p-AKT （all P<0.05）. ConclusionHDCA inhibits the PI3K/AKT signaling pathway by upregulating FXR expression， thereby inducing a reduction in the viability of steatosis hepatocytes.

Abstract: The differential expression and subcellular localization of single-cell proteins are closely related to the physiological state and pathological mechanisms of the body. The development of single-cell protein in situ imaging methods provides powerful tools for spatial single-cell proteomics research and single-cell protein profiling. This article summarizes the single-cell protein imaging methods developed in recent years, including the circulating immunofluorescence imaging methods based on ordered multi-round antibody incubation, mass spectrometry imaging based on metal element labeled antibodies, fluorescence imaging based on DNA-barcoded antibody, gene encoded fluorescence protein imaging and spectral imaging based on Raman spectroscopy or X-ray spectroscopy, with brief explanation of the imaging principles of these methods. It focuses on the multiple performance, imaging resolution and signal amplification performance of these methods, and analyzes their application characteristics in practical scientific research and clinical work, in the hope of providing some reference for the development of more revolutionary single-cell imaging methods, and promoting the development of biomedical and precision medicine.

Objective To investigate the distribution and antimicrobial resistance profiles of the clinical isolates from wound pus in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods All the bacterial strains were isolated from wound pus samples from 2015 to 2021.The isolates were identified according to conventional methods.Antimicrobial susceptibility test was conducted by disk diffusion method or commercial automated susceptibility testing systems according to CHINET-specified uniform protocol.The results are interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition).Results A total of 90856 bacterial strains were isolated from wound pus samples from 2015 to 2021,of which gram positive bacteria accounted for 36.0％ (32729/90856) and gram negative bacteria accounted for 64.0％ (58127/90856).The most common bacterial species were Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Enterococcus.About 88.9％ of these strains were isolated from inpatients and 11.1％ from outpatients.The strains collected from surgery department and internal medicine accounted for (53.4±3.6)％ (49191/90856) and (9.6±1.0)％ (8960/90856) on average over the 7-year period.E.coli showed low level resistance to carbapenems (1.1％).The prevalence of ESBLs-producing E.coli was 51.1％.More than 35％ of the E.coli isolates were resistant to cefotaxime,ciprofloxacin,and trimethoprim-sulfamethoxazole.The prevalence of ESBLs-producing K.pneumoniae was 29.7％.The prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae varied from 2015 to 2021,but reached the peak level (12.5％ and 12.7％) in 2020.However,other Enterobacterales species showed low resistance rates to carbapenems.The prevalence of ESBLs-producing Klebsiella oxytoca and Proteus was 18.3％ and 32.5％,respectively.About 13.1％ and 10.6％ of P.aeruginosa isolates were resistant to imipenem and meropenem,respectively.However,71.1％ and 72.4％ of A.baumannii isolates were resistant to imipenem and meropenem,respectively.The overall prevalence of MRSA was 22.7％ in wound pus samples over the 7-year period.Three vancomycin-resistant strains and 122 linezolid-resistant isolates were identified in Enterococcus faecalis.Thirty-one vancomycin-resistant strains and 11 linezolid-resistant strains were detected in Enterococcus faecium.Conclusions The overall prevalence of MRSA,vancomycin-resistant Enterococcus (VRE),linezolid-resistant Enterococcus (LRE),ESBLs-producing Enterobacterales,and carbapenem-resistant organisms (CRO) in the isolates from wound pus samples was relatively lower than the corresponding prevalence in the total clinical isolates collected in the CHINET program.This finding suggests that the antimicrobial resistance profile of bacterial isolates may vary with the source of clinical samples.Therefore,we should strengthen the antimicrobial resistance surveillance for the isolates from different sites of infection.

Objective To investigate the distribution and antimicrobial resistance profiles of the clinical isolates from wound pus in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods All the bacterial strains were isolated from wound pus samples from 2015 to 2021.The isolates were identified according to conventional methods.Antimicrobial susceptibility test was conducted by disk diffusion method or commercial automated susceptibility testing systems according to CHINET-specified uniform protocol.The results are interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition).Results A total of 90856 bacterial strains were isolated from wound pus samples from 2015 to 2021,of which gram positive bacteria accounted for 36.0％ (32729/90856) and gram negative bacteria accounted for 64.0％ (58127/90856).The most common bacterial species were Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Enterococcus.About 88.9％ of these strains were isolated from inpatients and 11.1％ from outpatients.The strains collected from surgery department and internal medicine accounted for (53.4±3.6)％ (49191/90856) and (9.6±1.0)％ (8960/90856) on average over the 7-year period.E.coli showed low level resistance to carbapenems (1.1％).The prevalence of ESBLs-producing E.coli was 51.1％.More than 35％ of the E.coli isolates were resistant to cefotaxime,ciprofloxacin,and trimethoprim-sulfamethoxazole.The prevalence of ESBLs-producing K.pneumoniae was 29.7％.The prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae varied from 2015 to 2021,but reached the peak level (12.5％ and 12.7％) in 2020.However,other Enterobacterales species showed low resistance rates to carbapenems.The prevalence of ESBLs-producing Klebsiella oxytoca and Proteus was 18.3％ and 32.5％,respectively.About 13.1％ and 10.6％ of P.aeruginosa isolates were resistant to imipenem and meropenem,respectively.However,71.1％ and 72.4％ of A.baumannii isolates were resistant to imipenem and meropenem,respectively.The overall prevalence of MRSA was 22.7％ in wound pus samples over the 7-year period.Three vancomycin-resistant strains and 122 linezolid-resistant isolates were identified in Enterococcus faecalis.Thirty-one vancomycin-resistant strains and 11 linezolid-resistant strains were detected in Enterococcus faecium.Conclusions The overall prevalence of MRSA,vancomycin-resistant Enterococcus (VRE),linezolid-resistant Enterococcus (LRE),ESBLs-producing Enterobacterales,and carbapenem-resistant organisms (CRO) in the isolates from wound pus samples was relatively lower than the corresponding prevalence in the total clinical isolates collected in the CHINET program.This finding suggests that the antimicrobial resistance profile of bacterial isolates may vary with the source of clinical samples.Therefore,we should strengthen the antimicrobial resistance surveillance for the isolates from different sites of infection.