Radiotherapy is a crucial treatment modality for head and neck tumors. However, while effectively killing tumor cells, it significantly disrupts the homeostasis of the oral microecology, which is closely associated with various complications such as radiation-induced oral mucositis. Literature review indicates that as radiotherapy doses accumulate and treatment durations extend, the richness and diversity of the oral microbiota show a declining trend, with the genus Streptococcus decreasing most markedly. In contrast, radiotherapy selectively promotes the proliferation of bacterial phyla such as Proteobacteria and Bacteroidetes, which are rich in opportunistic pathogens. Mechanistically, radiotherapy activates the nuclear factor-kappa B pathway, triggering chronic inflammation and oxidative stress, damaging the epithelial barrier, suppressing local immunity, and causing damage to organs such as the salivary glands. It can also induce systemic diseases via the oral-gut axis, forming a multi-level, interconnected pathogenic network. In terms of interventions, treatment strategies including probiotics and prebiotics have shown promising efficacy against side effects such as radiation-induced oral mucositis. Saliva-based oral microbiota transplantation is an emerging strategy that is expected to become widely utilized for restoring oral microecological balance. Existing interventions provide preliminary pathways for clinical practice, but this field still faces several key scientific questions. The association between oral microecology and systemic diseases remains largely correlative, lacking causal evidence. Furthermore, critical parameters for oral microbiota transplantation, such as donor screening criteria, transplantation protocols, and long-term safety, are not yet well-defined. Therefore, future research should focus on conducting large-scale clinical trials to establish standardized protocols and safety evaluation systems for oral microecological interventions, and explore combined treatment therapies such as probiotics, prebiotics, and microbiota transplantation to advance the development of personalized precision modulation. These will enable more effective management of radiotherapy-induced oral microecological dysbiosis and improve treatment outcomes and quality of life for patients with head and neck tumors.

ObjectiveTo explore the mechanisms of Qingchang Wenzhong Decoction （清肠温中方， QWD） in treating ulcerative colitis （UC）. MethodsA total of 100 male C57BL/6J mice were assigned to a pseudo-germ-free group （n=45） and a conventional group （n=55） using a random number table. Pseudo-germ-free model was established by giving antibiotic treatment and subsequently subjected to acute UC induction. After the model was successfully established， the 45 pseudo-germ-free acute UC mice were randomly allocated to a pseudo-germ-free model group， a pseudo-germ-free QWD group， and a pseudo-germ-free mesalazine group， with 15 mice in each group. The 55 conventional mice were randomly divided into a normal control group （n=10）， as well as a conventional model group， a conventional QWD group， and a conventional mesalazine group， with 15 mice in each group. Except for the normal control group， acute UC models were established in all other groups. Mice in the control group received no intervention. From day 32 of the experiment， mice in the pseudo-germ-free QWD group and the conventional QWD group were administered with QWD granules at a dose of 9.71 g/（kg·d） by gavage with deionized water， while those in the pseudo-germ-free mesalazine group and the conventional mesalazine group were given mesalazine enteric-coated tablets at a dose of 151.67 mg/（kg·d） by gavage. Mice in the remaining groups received an equal volume of deionized water once daily for 7 consecutive days. On day 25 of the experiment， six mice were randomly selected from both the pseudo-germ-free group and the conventional group to measure body weight， and fecal samples were collected for 16S rDNA sequencing to compare differences in gut microbiota， including operational taxonomic units （OTUs）， Shannon index， Observed_species index， and phylogenetic diversity （PD whole tree）. On day 39， body weight was measured in all groups， and the disease activity index （DAI） was evaluated. Colon length and colon wet weight were recorded. Histopathological changes in colonic tissues were assessed by hematoxylin and eosin （HE） staining， and histological injury scores were determined. In addition， the expression levels of mucopolysaccharides and mucin 2 （MUC2） in colonic tissues were measured. ResultsOn day 25， there was no significant difference in body weight between the pseudo-germ-free group and the conventional microbiota group （P＞0.05）. Compared to the conventional microbiota group， the pseudo-germ-free group showed significantly reduced OTUs， Shannon index， Observed_species index， and PD whole tree （P＜0.01）. On day 39， compared to the normal control group， mice in the conventional model group showed a significant decrease in the body weight and an increase in DAI， along with increased colon wet weight， shortened colon length， markedly elevated histopathological scores， and reduced expression of mucopolysaccharides and MUC2 （P＜0.01）. In contrast， no significant differences were observed in these parameters in the pseudo-germ-free model group （P＞0.05）. Compared to the conventional model group， the conventional QWD group showed significant improvement in all measured parameters， whereas the conventional mesalazine group showed reductions only in DAI scores and colon wet weight （P＜0.01）. No statistically significant differences were observed among the pseudo-germ-free model group， the pseudo-germ-free QWD group， and the pseudo-germ-free mesalazine group （P＞0.05）. ConclusionQWD may promote the reconstruction of the intestinal mucus barrier by regulating the intestinal flora， thereby exerting a therapeutic effect on acute UC.

ObjectiveTo explore the mechanisms of Qingchang Wenzhong Decoction （清肠温中方， QWD） in treating ulcerative colitis （UC）. MethodsA total of 100 male C57BL/6J mice were assigned to a pseudo-germ-free group （n=45） and a conventional group （n=55） using a random number table. Pseudo-germ-free model was established by giving antibiotic treatment and subsequently subjected to acute UC induction. After the model was successfully established， the 45 pseudo-germ-free acute UC mice were randomly allocated to a pseudo-germ-free model group， a pseudo-germ-free QWD group， and a pseudo-germ-free mesalazine group， with 15 mice in each group. The 55 conventional mice were randomly divided into a normal control group （n=10）， as well as a conventional model group， a conventional QWD group， and a conventional mesalazine group， with 15 mice in each group. Except for the normal control group， acute UC models were established in all other groups. Mice in the control group received no intervention. From day 32 of the experiment， mice in the pseudo-germ-free QWD group and the conventional QWD group were administered with QWD granules at a dose of 9.71 g/（kg·d） by gavage with deionized water， while those in the pseudo-germ-free mesalazine group and the conventional mesalazine group were given mesalazine enteric-coated tablets at a dose of 151.67 mg/（kg·d） by gavage. Mice in the remaining groups received an equal volume of deionized water once daily for 7 consecutive days. On day 25 of the experiment， six mice were randomly selected from both the pseudo-germ-free group and the conventional group to measure body weight， and fecal samples were collected for 16S rDNA sequencing to compare differences in gut microbiota， including operational taxonomic units （OTUs）， Shannon index， Observed_species index， and phylogenetic diversity （PD whole tree）. On day 39， body weight was measured in all groups， and the disease activity index （DAI） was evaluated. Colon length and colon wet weight were recorded. Histopathological changes in colonic tissues were assessed by hematoxylin and eosin （HE） staining， and histological injury scores were determined. In addition， the expression levels of mucopolysaccharides and mucin 2 （MUC2） in colonic tissues were measured. ResultsOn day 25， there was no significant difference in body weight between the pseudo-germ-free group and the conventional microbiota group （P＞0.05）. Compared to the conventional microbiota group， the pseudo-germ-free group showed significantly reduced OTUs， Shannon index， Observed_species index， and PD whole tree （P＜0.01）. On day 39， compared to the normal control group， mice in the conventional model group showed a significant decrease in the body weight and an increase in DAI， along with increased colon wet weight， shortened colon length， markedly elevated histopathological scores， and reduced expression of mucopolysaccharides and MUC2 （P＜0.01）. In contrast， no significant differences were observed in these parameters in the pseudo-germ-free model group （P＞0.05）. Compared to the conventional model group， the conventional QWD group showed significant improvement in all measured parameters， whereas the conventional mesalazine group showed reductions only in DAI scores and colon wet weight （P＜0.01）. No statistically significant differences were observed among the pseudo-germ-free model group， the pseudo-germ-free QWD group， and the pseudo-germ-free mesalazine group （P＞0.05）. ConclusionQWD may promote the reconstruction of the intestinal mucus barrier by regulating the intestinal flora， thereby exerting a therapeutic effect on acute UC.

Aim To establish the pyroptosis model of rat chondrocytes induced by tumor necrosis factor α(TNF-α)in order to study the effect of lysine acetyl-transferase 7(KAT7)on pyroptosis of chondrocytes.Methods Chondrocytes of rat knee joint were isolated by type Ⅱ collagenase digestion,and were identified by toluidine blue staining and Col Ⅱ immunofluorescence.CCK-8 was used to evaluate cell viability.Western blot was used to detect the expression of pyroptosis-related proteins NLRP3,GSDMD,caspase-8 and KAT7 in cells intervened with TNF-α,adenovirus overexpression of KAT7(KAT7-oe)and KAT7 inhibitor WM-3835.The microstructure of the cells was observed by scanning e-lectron microscopy.Pyroptosis was detected by TUNEL staining,and the expression of pyroptosis-related pro-tein and KAT7 was detected by immunofluorescence.Results Compared with the empty virus group,KAT7-oe inhibited cell viability,promoted the expression of pyroptosis-related proteins,and TNF-α enhanced this effect.At the same time,the expression of KAT7 and pyroptosis-related proteins in the TNF-α stimulation group increased,and WM-3835 reduced the related proteins expression.Electron microscopy showed that KAT7-oe caused cell swelling,deformation,membrane perforation and rupture,while WM-3835 could restore cell morphology.TUNEL staining and immunofluores-cence results also confirmed that KAT7-oe induced chondrocyte pyroptosis,and WM-3835 could down-reg-ulate the fluorescence of pyroptosis-related proteins.Conclusions The expression of KAT7 increases in rat chondrocyte pyroptosis model,and the intervention of KAT7 expression affects signal molecules related to py-roptosis pathway,suggesting that KAT7 may be related to chondrocyte pyroptosis.

Objective To explore method for improving the colonization efficiency of Helicobacter pylori(Hp)in the mouse stomach and to determine if the proton pump inhibitor(PPI)pantoprazole can act as a colonization adjuvant to enhance Hp colonization,with the aim of providing an effective tool for establishing an Hp infection mouse model.Methods The Hp Sydney strain 1(SS1)was introduced and solid plate and liquid culture systems were established.The effects of different doses of pantoprazole on gastric acid secretion in mice were compared.The impact of Hp inoculation,alone or combined with pantoprazole pretreatment,on Hp colonization efficiency was analyzed using rapid urease tests,bacterial plate cultures,and TaqMan quantitative polymerase chain reaction.Results PPI pretreatment inhibited gastric acid secretion and promoted Hp colonization in the mouse stomach,to some extent.Conclusions PPI can serve as colonization adjuvants to enhanc e the efficiency of constructing Hp infection mouse models.

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.

Aim To establish the pyroptosis model of rat chondrocytes induced by tumor necrosis factor α(TNF-α)in order to study the effect of lysine acetyl-transferase 7(KAT7)on pyroptosis of chondrocytes.Methods Chondrocytes of rat knee joint were isolated by type Ⅱ collagenase digestion,and were identified by toluidine blue staining and Col Ⅱ immunofluorescence.CCK-8 was used to evaluate cell viability.Western blot was used to detect the expression of pyroptosis-related proteins NLRP3,GSDMD,caspase-8 and KAT7 in cells intervened with TNF-α,adenovirus overexpression of KAT7(KAT7-oe)and KAT7 inhibitor WM-3835.The microstructure of the cells was observed by scanning e-lectron microscopy.Pyroptosis was detected by TUNEL staining,and the expression of pyroptosis-related pro-tein and KAT7 was detected by immunofluorescence.Results Compared with the empty virus group,KAT7-oe inhibited cell viability,promoted the expression of pyroptosis-related proteins,and TNF-α enhanced this effect.At the same time,the expression of KAT7 and pyroptosis-related proteins in the TNF-α stimulation group increased,and WM-3835 reduced the related proteins expression.Electron microscopy showed that KAT7-oe caused cell swelling,deformation,membrane perforation and rupture,while WM-3835 could restore cell morphology.TUNEL staining and immunofluores-cence results also confirmed that KAT7-oe induced chondrocyte pyroptosis,and WM-3835 could down-reg-ulate the fluorescence of pyroptosis-related proteins.Conclusions The expression of KAT7 increases in rat chondrocyte pyroptosis model,and the intervention of KAT7 expression affects signal molecules related to py-roptosis pathway,suggesting that KAT7 may be related to chondrocyte pyroptosis.

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.