Hypochlorous acid/hypochlorite(HClO/ClO-)plays a key role in biological processes and is commonly used as a disinfectant in drinking water.However,excessive intake of HClO/ClO-can oxidize biomolecules like DNA,RNA,and proteins,causing organ damage.Diseases such as rheumatoid arthritis and Alzheimer's disease can also lead to overproduction of HClO/ClO-.Therefore,accurately detecting HClO/ClO-levels is crucial.In this study,an HClO/ClO-fluorescent probe,NC-TPA-PPh3,was designed and synthesized,with a triphenylamine core as the fluorescent unit,carbon-carbon double bonds as recognition sites,and a quaternary ammonium salt for mitochondria targeting,forming a D-π-A structure.This probe had a fluorescence lifetime of 3.71 ns and a fluorescence quantum yield of 0.51.Upon exposure to HClO/ClO-,the maximum fluorescence emission wavelength of the probe in DMSO/H2O(9∶1,V/V,pH=7.4)solution(20 μmol/L)shifted from 550 nm to 430 nm,with a fluorescence intensity increase of 35.7 times compared to blank probe solution,allowing for selective recognition of HClO/ClO-.The probe also exhibited a large Stokes shift(130 nm)and a low limit of detection(LOD)of 9.16×10-8 mol/L.Based on characterization by proton nuclear magnetic resonance(1H NMR),electrospray ionization-mass spectrometry(ESI-MS),scanning electron microscopy(SEM)and theoretical calculations,it was speculated that NC-TPA-PPh3 recognized HClO/ClO-through oxidative cleavage of the C=C bond in the probe,generating TPA-CHO with lower water solubility and a smaller conjugated structure.This disrupted the D-π-A structure,blocking intramolecular charge transfer(ICT),causing the fluorescence emission peak to blue-shift from 550 nm to 430 nm.Additionally,this process induced an aggregation-induced fluorescence effect,significantly enhancing the fluorescence intensity at 430 nm.

Objective:To investigate the effects of metformin on esophageal squamous cell carcinoma cell growth, migration and angiogenesis by regulating the expression of ALKBH3.Methods:Human esophageal cancer TE-1 cells were treated with different concentrations (0, 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L) of metformin, and they were divided into a blank control group, low- (0.5 mmol/L), medium- (1.0 mmol/L), and high- (2.0 mmol/L) concentration metformin groups, a metformin (2.0 mmol/L) +pcDNA-NC group, and a metformin (2.0 mmol/L) +pcDNA-ALKBH3 group. The cell viability was determined by the CCK-8 method. The cell proliferation ability was detected by the clone formation assay. The cell migration and invasion abilities were examined by the Transwell assay. The cell apoptosis was detected by flow cytometry. The tube formation ability of cells was detected by the angiogenesis assay. A xenograft tumor model was constructed using 4- to 6-week-old male BALB/c thymus-less nude mice, which were divided into a model control group, a metformin group, a metformin+pcDNA-NC group, and a metformin+pcDNA-ALKBH3 group using a random number table method, and with six in each group. And the volume and weight of the tumor were measured. The protein expression levels of apoptosis-related proteins Bcl-2, Bax, ALKBH3 and vascular endothelial growth factor A (VEGF-A) were detected by Western blotting. The expression of CD31 protein was detected by immunohistochemistry.Results:After treating TE-1 cells with 0, 0.5, 1.0, 2.0, 4.0, and 8.0 mmol/L metformin for 48 hours, the cell viability was (100.00±0.00) %, (90.31±5.23) %, (81.25±8.65) %, (63.52±6.80) %, (54.64±5.35) %, and (31.48±4.21) %, respectively, with a statistically significant difference ( F=98.11, P<0.001). There were statistically significant differences in cell viability between 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L and 0 mmol/L (all P<0.05). The IC 50 of metformin for TE-1 cells was 4.46 mmol/L. The numbers of colony formations of TE-1 cells in the blank control group, low-, medium-, and high-concentration metformin groups, metformin+pcDNA-NC group, and metformin+pcDNA-ALKBH3 group were 153.15±13.55, 134.80±11.62, 116.24±10.43, 93.17±8.85, 89.39±8.46, 110.26±7.21, respectively, with a statistically significant difference ( F=34.28, P<0.001); the numbers of colony formations of TE-1 cells in the metformin groups at different concentrations decreased significantly with the increase in metformin concentration (both P<0.05); compared with the metformin+pcDNA-NC group, the number of colony formations of cells in the metformin+pcDNA-ALKBH3 group increased ( P<0.05). The numbers of migration of TE-1 cells of 6 groups were 152.13±13.40, 133.85±10.72, 115.28±8.64, 91.16±7.89, 85.39±7.23, 116.85±8.36, the numbers of invasion were 135.22±10.77, 112.07±9.53, 86.30±7.45, 69.53±6.74, 65.81±5.65, 79.80±6.32, respectively, with statistically significant differences ( F=41.35, P<0.001; F=69.06, P<0.001); the numbers of migrated and invaded cells in the metformin groups at different concentrations decreased significantly with the increase in metformin concentration (all P<0.05); compared with the metformin+pcDNA-NC group, the numbers of migrated and invaded cells in the metformin+pcDNA-ALKBH3 group increased significantly (both P<0.05). The apoptosis rates of TE-1 cells in 6 groups were (3.22±1.13) %, (13.82±1.90) %, (22.67±2.53) %, (29.18±3.24) %, (26.84±2.75) %, and (16.36±1.63) %, respectively, with a statistically significant difference ( F=103.66, P<0.001); the apoptosis rates of cells in the metformin groups at different concentrations gradually increased with the increase in metformin concentration (both P<0.05); compared with the metformin+pcDNA-NC group, the apoptosis rate of cells in the metformin+pcDNA-ALKBH3 group was relatively lower ( P<0.05). The tubular structure of cells in blank control group was intact, and there were different degrees of damage to the tubular structure of cells in the low-, medium-, high- concentration metformin groups, the degree of damage to the tubular structure of cells in the metformin+pcDNA-ALKBH3 group was reduced. The numbers of cellular tubular structures of TE-1 cells in the 6 groups were 38.35±3.20, 27.15±2.64, 15.92±3.14, 7.39±1.50, 8.61±1.37, and 29.33±4.20, respectively, with a statistically significant difference ( F=113.92, P<0.001); the number of cellular tubular structures in the low-, medium-, and high- concentration metformin groups gradually decreased (both P<0.05); the number of cellular tubular structures in the metformin+pcDNA-ALKBH3 group was more than that in the metformin+pcDNA-NC group ( P<0.05). There were statistically significant differences in the protein expressions of Bcl-2, Bax, ALKBH3, and VEGF-A in TE-1 cells among 6 groups ( F=56.36, P<0.001; F=57.26, P<0.001; F=159.30, P<0.001; F=132.89, P<0.001); compared with the blank control group, the protein expressions of Bcl-2, ALKBH3, and VEGF-A in the metformin groups at different concentrations decreased, while the protein expression of Bax increased (all P<0.05); compared with the metformin+pcDNA-NC group, the protein expressions of Bcl-2, ALKBH3, and VEGF-A in the metformin+pcDNA-ALKBH3 group increased, and the expression level of Bax decreased (all P<0.05). The weights of tumors in the model control group, metformin group, metformin+pcDNA-NC group, and metformin+pcDNA-ALKBH3 group were (1.16±0.12), (0.46±0.05), (0.50±0.06), (1.19±0.14) g, the volumes of tumors were (878.36±108.93), (413.59±50.23), (439.78±51.39), (793.75±96.98) mm 3, with statistically significant differences ( F=96.61, P<0.001; F=51.90, P<0.001); the weight of tumors were lower and the volume of tumors were smaller in the metformin group than those in the model control group (both P<0.05), the weight of tumors were higher and the volume of tumors were bigger in the metformin+pcDNA-ALKBH3 group than those in the metformin group and the metformin+pcDNA-NC group (all P<0.05). CD31 was mainly distributed in the cytoplasm and cell membrane of tumor cells. There were statistically significant differences in the positive rates of CD31 and the protein expression levels of VEGF-A in transplanted tumor tissues among 4 groups ( F=7.12, P=0.002; F=48.81, P<0.001); the positive rate of CD31 and the protein expression level of VEGF-A in the metformin group were lower than those in the model control group; the positive rate of CD31 and the protein expression level of VEGF-A in the metformin+pcDNA-ALKBH3 group were higher than those in the metformin group and the metformin+pcDNA-NC group (all P<0.05) . Conclusions:Metformin may inhibit the proliferation, migration, and tumor angiogenesis of esophageal squamous cell carcinoma by reducing ALKBH3 expression.

Ginsenoside Rg_2(GRg2) is a triterpenoid compound found in Panax notoginseng. This study explored its effects and mechanisms on diabetic retinopathy and angiogenesis. The study employed endothelial cell models induced by glucose or vascular endothelial growth factor(VEGF), the chorioallantoic membrane(CAM) model, the oxygen-induced retinopathy(OIR) mouse model, and the db/db mouse model to evaluate the therapeutic effects of GRg2 on diabetic retinopathy and angiogenesis. Transwell assays and endothelial tube formation experiments were conducted to assess cell migration and tube formation, while vascular area measurements were applied to detect angiogenesis. The impact of GRg2 on the retinal structure and function of db/db mice was evaluated through retinal thickness and electroretinogram(ERG) analyses. The study investigated the mechanisms of GRg2 by analyzing the activation of Yes-associated protein(YAP) and Toll-like receptors(TLRs) pathways. The results indicated that GRg2 significantly reduced cell migration numbers and tube formation lengths in vitro. In the CAM model, GRg2 exhibited a dose-dependent decrease in the vascular area ratio. In the OIR model, GRg2 notably decreased the avascular and neovascular areas, ameliorating retinal structural disarray. In the db/db mouse model, GRg2 increased the total retinal thickness and enhanced the amplitudes of the a-wave, b-wave, and oscillatory potentials(OPs) in the ERG, improving retinal structural disarray. Transcriptomic analysis revealed that the TLR signaling pathway was significantly down-regulated following YAP knockdown, with PCR results consistent with the transcriptome sequencing findings. Concurrently, GRg2 downregulated the expression of Toll-like receptor 4(TLR4), TNF receptor-associated factor 6(TRAF6), and nuclear factor-kappaB(NF-κB) proteins in high-glucose-induced endothelial cells. Collectively, GRg2 inhibits cell migration and tube formation and significantly reduces angiogenesis in CAM and OIR models, improving retinal structure and function in db/db mice, with its pharmacological mechanism likely involving the down-regulation of YAP expression.
Animals ; Ginsenosides/pharmacology* ; Diabetic Retinopathy/physiopathology* ; Mice ; YAP-Signaling Proteins ; Humans ; Male ; Signal Transduction/drug effects* ; Cell Movement/drug effects* ; Adaptor Proteins, Signal Transducing/genetics* ; Mice, Inbred C57BL ; Neovascularization, Pathologic/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Panax notoginseng/chemistry* ; Endothelial Cells/metabolism* ; Transcription Factors/genetics* ; Angiogenesis

This study aims to explore the protective effect of Chaihu Jia Longgu Muli Decoction on rats with heart failure after myocardial infarction, and to clarify its possible mechanisms, providing a new basis for basic research on the mechanism of classic Chinese medicinal formula-mediated inflammatory response in preventing and treating heart failure induced by apoptosis after myocardial infarction. A heart failure model after myocardial infarction was established in rats by coronary artery ligation. The rats were divided into sham group, model group, and low, medium, and high-dose groups of Chaihu Jia Longgu Muli Decoction, with 10 rats in each group. The low-dose, medium-dose, and high-dose groups of Chaihu Jia Longgu Muli Decoction were given 6.3, 12.6, and 25.2 g·kg~(-1) doses by gavage, respectively. The sham group and model group were given an equal volume of distilled water by gavage once daily for four consecutive weeks. Cardiac function was assessed using color Doppler echocardiography. Myocardial pathology was detected by hematoxylin-eosin(HE) staining, apoptosis was measured by TUNEL assay, and mitophagy was observed by transmission electron microscopy. The levels of tumor necrosis factor-α(TNF-α), interleukin(IL)-1β, and N-terminal pro-B-type natriuretic peptide(NT-proBNP) in serum were detected by enzyme-linked immunosorbent assay(ELISA). The expression of apoptosis-related proteins B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), and cleaved caspase-3 was detected by Western blot. Additionally, the expression of phosphorylated nuclear transcription factor-κB(NF-κB) p65(p-NF-κB p65)(upstream) and nuclear factor kappa B inhibitor alpha(IκBα)(downstream) in the NF-κB signaling pathway was assessed by Western blot. The results showed that compared with the sham group, left ventricular ejection fraction(LVEF) and left ventricular short axis shortening(LVFS) in the model group were significantly reduced, while left ventricular end diastolic diameter(LVEDD) and left ventricular end systolic diameter(LVESD) increased significantly. Myocardial tissue damage was severe, with widened intercellular spaces and disorganized cell arrangement. The apoptosis rate was increased, and mitochondria were enlarged with increased vacuoles. Levels of TNF-α, IL-1β, and NT-proBNP were elevated, indicating an obvious inflammatory response. The expression of pro-apoptotic factors Bax and cleaved caspase-3 increased, while the anti-apoptotic factor Bcl-2 decreased. The expression of p-NF-κB p65 was upregulated, and the expression of IκBα was downregulated. In contrast, the Chaihu Jia Longgu Muli Decoction groups showed significantly improved of LVEF, LVFS and decreased LVEDD, LVESD compared to the model group. Myocardial tissue damage was alleviated, and intercellular spaces were reduced. The apoptosis rate decreased, mitochondrial volume decreased, and the levels of TNF-α, IL-1β, and NT-proBNP were lower. The expression of pro-apoptotic factors Bax and cleaved caspase-3 decreased, while the expression of the anti-apoptotic factor Bcl-2 increased. Additionally, the expression of p-NF-κB p65 decreased, while IκBα expression increased. In summary, this experimental study shows that Chaihu Jia Longgu Muli Decoction can reduce the inflammatory response and apoptosis rate in rats with heart failure after myocardial infarction, which may be related to the regulation of the IκBα/NF-κB signaling pathway.
Animals ; Apoptosis/drug effects* ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Myocardial Infarction/physiopathology* ; Male ; NF-kappa B/genetics* ; Heart Failure/etiology* ; Rats, Sprague-Dawley ; Signal Transduction/drug effects* ; NF-KappaB Inhibitor alpha/genetics* ; Humans ; Tumor Necrosis Factor-alpha/genetics*

Emodin is a hydroxyanthraquinone compound that is widely distributed and has multiple pharmacological activities, including anti-diarrheal, anti-inflammatory, and liver-protective effects. Research indicates that emodin may be one of the main components responsible for inducing hepatotoxicity. However, studies on the mechanisms of liver injury are relatively limited, particularly those related to bile acids(BAs) metabolism. This study aims to systematically investigate the effects of different dosages of emodin on BAs metabolism, providing a basis for the safe clinical use of traditional Chinese medicine(TCM)containing emodin. First, this study evaluated the safety of repeated administration of different dosages of emodin over a 5-week period, with a particular focus on its impact on the liver. Next, the composition and content of BAs in serum and liver were analyzed. Subsequently, qRT-PCR was used to detect the mRNA expression of nuclear receptors and transporters related to BAs metabolism. The results showed that 1 g·kg~(-1) emodin induced hepatic damage, with bile duct hyperplasia as the primary pathological manifestation. It significantly increased the levels of various BAs in the serum and primary BAs(including taurine-conjugated and free BAs) in the liver. Additionally, it downregulated the mRNA expression of farnesoid X receptor(FXR), retinoid X receptor(RXR), and sodium taurocholate cotransporting polypeptide(NTCP), and upregulated the mRNA expression of cholesterol 7α-hydroxylase(CYP7A1) in the liver. Although 0.01 g·kg~(-1) and 0.03 g·kg~(-1) emodin did not induce obvious liver injury, they significantly increased the level of taurine-conjugated BAs in the liver, suggesting a potential interference with BAs homeostasis. In conclusion, 1 g·kg~(-1) emodin may promote the production of primary BAs in the liver by affecting the FXR-RXR-CYP7A1 pathway, inhibit NTCP expression, and reduce BA reabsorption in the liver, resulting in BA accumulation in the peripheral blood. This disruption of BA homeostasis leads to liver injury. Even doses of emodin close to the clinical dose can also have a certain effect on the homeostasis of BAs. Therefore, when using traditional Chinese medicine or formulas containing emodin in clinical practice, it is necessary to regularly monitor liver function indicators and closely monitor the risk of drug-induced liver injury.
Emodin/administration & dosage* ; Bile Acids and Salts/metabolism* ; Animals ; Male ; Liver/injuries* ; Chemical and Drug Induced Liver Injury/genetics* ; Drugs, Chinese Herbal/adverse effects* ; Humans ; Rats, Sprague-Dawley ; Mice ; Rats

Pulpotomy, which belongs to vital pulp therapy, has become a strategy for managing pulpitis in recent decades. This minimally invasive treatment reflects the recognition of preserving healthy dental pulp and optimizing long-term patient-centered outcomes. Pulpotomy is categorized into partial pulpotomy (PP), the removal of a partial segment of the coronal pulp tissue, and full pulpotomy (FP), the removal of whole coronal pulp, which is followed by applying the biomaterials onto the remaining pulp tissue and ultimately restoring the tooth. Procedural decisions for the amount of pulp tissue removal or retention depend on the diagnostic of pulp vitality, the overall treatment plan, the patient's general health status, and pulp inflammation reassessment during operation. This statement represents the consensus of an expert committee convened by the Society of Cariology and Endodontics, Chinese Stomatological Association. It addresses the current evidence to support the application of pulpotomy as a potential alternative to root canal treatment (RCT) on mature permanent teeth with pulpitis from a biological basis, the development of capping biomaterial, and the diagnostic considerations to evidence-based medicine. This expert statement intends to provide a clinical protocol of pulpotomy, which facilitates practitioners in choosing the optimal procedure and increasing their confidence in this rapidly evolving field.
Humans ; Calcium Compounds/therapeutic use* ; Consensus ; Dental Pulp ; Dentition, Permanent ; Oxides/therapeutic use* ; Pulpitis/therapy* ; Pulpotomy/standards*

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 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.