Objective To establish two golden hamster models infected with hypervirulent Klebsiella pneumoniae via aerosolized intratracheal(i.t.)and intranasal(i.n.)inoculation,and compare their properties.Methods Golden hamsters of 4 to 5 weeks old were exposed to K.pneumoniae NTUH-K2044 via i.t.route and i.n.route respectively.The survival of these golden hamsters was observed and recorded within 14 days of infection before the 50%lethal dose(LD50),survival rate,bacterial respiratory deposition rate,lung bacterial load and histopathology of the infected golden hamsters in the two groups were detected.Results The LD50 of the i.t.route(3×104 CFU)was lower than that of the i.n.route(7×105 CFU)in golden hamsters.After 4×106 CFU NTUH-K2044 infection,the golden hamsters in the i.t.group had 96.46%of the bacteria deposited and colonized in the lung,developed lobar pneumonia and died without exception within 4 days of infection,while those in the i.n.group had 95.62%of the bacteria deposited in the mouth and nose initially before the bacteria moved down to the trachea for colonization and were cleared out gradually.This group mainly acquired bronchopneumonia with relatively mild lung lesions,with a 14-day survival rate of 70%.Conclusion Inoculation routes can make a difference to the disease type of respiratory tract infections in animal models.The i.t.route mainly causes lobar pneumonia with severe lung lesions,while the i.n.route leads to bronchopneumonia with mild lung lesions.The two animal models established above may be utilized for pathogenesis investigation and treatment efficacy evaluation of Klebsiella pneumoniae.

ObjectiveTo investigate the effect of linalool against acute liver injury induced by aflatoxin B₁（AFB₁） in rats and explore its protective mechanism. MethodTwenty male SPF SD rats were randomly divided into three groups： Control （n=6）， AFB₁ （n=7）， and linalool （n=7） groups. Linalool solution （200 mg·kg^-1） was administered preventatively for 14 days， while the control and AFB₁ groups intragastrically received an equivalent volume of double distilled water. After preventative administration of linalool， AFB₁ solution （1 mg·kg^-1， dissolved in saline） was intraperitoneally injected for two consecutive days to induce acute liver injury in rats. Samples were collected and processed 14 days after model establishment. Pathological changes in liver tissue of rats were observed using Hematoxylin-eosin（HE） staining and Masson staining. Biochemical detection was performed to measure the levels of alanine transaminase（ALT）， aspartate transaminase（AST）， γ-glutamyl transferase（GGT）， lactate dehydrogenase（LDH）， alkaline phosphatase（ALP）， total bilirubin（TBil）， direct bilirubin（DBil）， indirect bilirubin（IBil）， malondialdehyde（MDA）， superoxidedismutase（SOD）， catalase（CAT） ， glutathione（GSH）， Fe³⁺， and Fe²⁺ in the liver tissue. Western blot was adopted to assess protein expression levels of nuclear factor-erythroid 2-related factor 2（Nrf2） and heme oxygenase-1（HO-1）. Molecular docking was performed to verify the binding between linalool and key proteins of the Nrf2/HO-1 signaling pathway. Molecular dynamics techniques were used to confirm the stability and affinity of linalool binding with key proteins of the Nrf2/HO-1 signaling pathway. ResultPathological results showed that compared to that in the AFB₁ group， the liver structure in the linalool group tended to be normal， with a significant decrease in blue collagen fibers. The linalool group exhibited significantly reduced levels of ALT， AST， GGT， LDH， ALP， TBil， DBil， and IBil （P<0.01）， Fe³⁺ and Fe²⁺ content， and oxidative stress marker MDA （P<0.01）. The levels of antioxidants SOD， CAT， and GSH significantly increased （P<0.01）. Molecular docking showed a molecular docking energy between linalool and Nrf2 and HO-1 targets of -5.495 6 and -5.199 4 kcal·mol^-1（1 cal≈4.186 J）， respectively. Molecular dynamics results indicated strong affinity in the binding of linalool with Nrf2 and HO-1. Western blot revealed a significant increase in Nrf2 protein expression （P<0.05） and a decrease in HO-1 protein expression （P<0.01） in the linalool group. ConclusionLinalool may protect against AFB₁-induced acute liver injury by modulating the Nrf2/HO-1 ferroptosis signaling pathway to inhibit liver cell ferroptosis and regulate hepatic oxidative stress levels.

Objective : To investigate the drug resistance and pathogenicity of six clinical isolates of Klebsiella pneu- moniae (Kp) ，and to provide a basis for prevention and treatment of Kp infection． Methods : The six strains from different hospitals were isolated ，cultured ，and identified by species-specific gene khe． Their whole genome se- quences (WGS) were obtained using next-generation sequencing technology (NGS) ．Based on the WGS，the cap- sular serotypes，sequence types (ST) and drug-resistance genes of six strains were identified．The capsular sero- type genes and virulence genes were validated or identified using PCR. Broth microdilution tests were conducted to validate their drug susceptibility，and mice were challenged with Kp aerosols by MicroSprayer aerosolizer to evaluate their pathogenicity. Results : The six strains were all serotype K2 but belonged to four ST types ( ST14 ，ST65， ST700，and ST86) ，and collectively carried six virulence genes and 23 drug-resistance genes．All the six strains were resistant to ampicillin，but only one strain was multidrug-resistant．Four strains exhibited high mucoid charac- teristics．Five strains could cause mortality in mice，which were preliminary identified as high virulence strains. Conclusion For the six Kp clinical isolates from different sources，only one strain named NY 13294 is both multi- drug-resistant and highly virulent，and other four highly virulent strains are resistant to one or two types of antibiot- ics.

Objective:To develop a prediction tool for 6-year incident risk of frailty among Chinese older adults aged 65 years or above.Methods:Data from the Chinese Longitudinal Healthy Longevity Survey from 2002 to 2018 was used, including 13 676 older adults aged 65 years or above who were free of frailty at baseline. Key predictors of frailty were identified via the least absolute shrinkage and selection operator (LASSO) method, and were thereafter used to predict the incident frailty based on the Cox proportional hazards regression model. The model was internally validated by 2 000 Bootstrap resamples and evaluated for the performance of discrimination and calibration using the area under the receiver operating characteristic curve (AUC) and calibration curve, respectively. The net benefit of the developed prediction tool was evaluated by decision-curve analysis.Results:The M( Q1, Q3) age and follow-up time of the participants were 81.0 (71.0, 90.0) years and 6.0 (4.1, 9.2) years, respectively. A total of 4 126 older persons (30.2%) were recorded with frailty incidents during the follow-up, with the corresponding incidence density of 41.8/1 000 person-years. A total of 15 key predictors of frailty were selected by LASSO, namely, age, sex, race, education years, meat consumption, tea drinking, performing housework, raising domestic animals, playing cards or mahjong, and baseline status of visual function, activities of the daily living score, instrumental activities of the daily living score, hypertension, heart disease, and self-rated health. The prediction model was internally validated with an AUC of 0.802, with the max Youden's index of 0.467 at a risk threshold of 19.0%. The calibration curve showed high consistency between predicted probabilities and observed proportions of frailty events. The decision curve indicated that higher net benefits could be obtained via the prediction model than did strategies based on intervention in all or none participants for any risk threshold less than 59%, and the model-based net benefit was estimated to be 0.10 at a risk threshold of 19.0%. Conclusions:The herein developed 6-year incident risk prediction model of frailty, based on easily accessible questionnaires and physical examination variables, has good predictive performance. It has application potential in identifying populations at high risk of incident frailty.

ObjectiveMetabolomics was utilized to investigate the preventive effect of notoginseng total saponins（NTS） on aspirin（acetyl salicylic acid， ASA）-induced small bowel injury in rats. MethodFifty male SD rats were randomly divided into normal and model groups， NTS high-dose and low-dose groups（62.5， 31.25 mg·kg^-1）， and positive drug group（omeprazole 2.08 mg·kg^-1+rebamipide 31.25 mg·kg^-1）， with 10 rats in each group. Except for the normal group， rats in other groups were given ASA enteric-coated pellets 10.41 mg·kg^-1 daily to establish a small intestine injury model. On this basis， each medication group was gavaged daily with the corresponding dose of drug， and the normal group and the model group were gavaged with an equal amount of drinking water. Changes in body mass and fecal characteristics of rats were recorded and scored during the period. After 14 weeks of administration， small intestinal tissues of each group were taken for hematoxylin-eosin（HE） staining， scanning electron microscopy to observe the damage， and the apparent damage of small intestine was scored. Serum from rats in the normal group， the model group， and the NTS high-dose group was taken and analyzed for metabolomics by ultra-performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry（UPLC-Q-Exactive Orbitrap MS）， and the data were processed by multivariate statistical analysis， the potential biomarkers were screened by variable importance in the projection（VIP） value≥1.0， fold change（FC）≥1.5 or ≤0.6 and t-test P<0.05， and pathway enrichment analysis of differential metabolites was performed in conjunction with Human Metabolome Database（HMDB） and Kyoto Encyclopedia of Genes and Genomes（KEGG）. ResultAfter 14 weeks of administration， the average body mass gain of the model group was lower than that of the normal group， and the NTS high-dose group was close to that of the normal group. Compared with the normal group， the fecal character score of rats in the model group was significantly increased（P<0.05）， and compared with the model group， the scores of the positive drug group and the NTS high-dose group were reduced， but the difference was not statistically significant. HE staining and scanning electron microscopy results showed that NTS could significantly improve ASA-induced small intestinal injury， compared with the normal group， the small bowel injury score of the model group was significantly increased（P<0.01）， compared with the model group， the small bowel injury scores of the NTS low and high dose groups were significantly reduced（P<0.05， P<0.01）. Serum metabolomics screened a total of 75 differential metabolites between the normal group and the model group， of which 55 were up-regulated and 20 were down-regulated， 76 differential metabolites between the model group and the NTS groups， of which 14 were up-regulated and 62 were down-regulated. NTS could modulate three differential metabolites（salicylic acid， 3-hydroxybenzoic acid and 4-hydroxybenzoic acid）， which were involved in 3 metabolic pathways， namely， the bile secretion， the biosynthesis of folic acid， and the biosynthesis of phenylalanine， tyrosine and tryptophan. ConclusionNTS can prevent ASA-induced small bowel injury， and the underlying mechanism may be related to the regulation of bile secretion and amino acid metabolic pathways in rats.

Objective:To construct a special training program for oncology nurses on immunotherapy, and to lay the foundation for the promotion of standardized care of immunotherapy.Methods:The first draft of the immunotherapy training program for oncology nurses was initially constructed through literature review and semi-structured interviews; the final draft of the immunotherapy training program for oncology nurses was determined by using the Delphi expert correspondence method from October to December, 2023.Results:Two rounds of expert correspondence were conducted, and the effective recovery rates of the questionnaires were 15/15, with the expert authority coefficients of 0.847 and 0.867, and Kendall harmony coefficients of 0.207 and 0.212, respectively (both P<0.01). The final established special training program for immunotherapy for oncology nurses included 3 primary indicators, 17 secondary indicators, and 58 tertiary indicators. Conclusions:The construction process of the special training program for oncology nurses′immunotherapy is rigorous and scientific, with obvious speciality characteristics, which can provide a feasible program for the training of oncology nurses′immunotherapy nursing.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.

Objective To understand the changing distribution and antimicrobial resistance profiles of Proteus,Morganella and Providencia in hospitals across China from January 1,2015 to December 31,2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods Antimicrobial susceptibility testing was carried out following the unified CHINET protocol.The results were interpreted in accordance with the breakpoints in the 2021 Clinical & Laboratory Standards Institute(CLSI)M100(31 st Edition).Results A total of 32 433 Enterobacterales strains were isolated during the 7-year period,including 24 160 strains of Proteus,6 704 strains of Morganella,and 1 569 strains of Providencia.The overall number of these Enterobacterales isolates increased significantly over the 7-year period.The top 3 specimen source of these strains were urine,lower respiratory tract specimens,and wound secretions.Proteus,Morganella,and Providencia isolates showed lower resistance rates to amikacin,meropenem,cefoxitin,cefepime,cefoperazone-sulbactam,and piperacillin-tazobactam.For most of the antibiotics tested,less than 10％of the Proteus and Morganella strains were resistant,while less than 20％of the Providencia strains were resistant.The prevalence of carbapenem-resistant Enterobacterales(CRE)was 1.4％in Proteus isolates,1.9％in Morganella isolates,and 15.6％in Providencia isolates.Conclusions The overall number of clinical isolates of Proteus,Morganella and Providencia increased significantly in the 7-year period from 2015 to 2021.The prevalence of CRE strains also increased.More attention should be paid to antimicrobial resistance surveillance and rational antibiotic use so as to prevent the emergence and increase of antimicrobial resistance.

Objective To understand the changing distribution and antimicrobial resistance profiles of Klebsiella strains in 52 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Antimicrobial susceptibility testing was carried out according to the unified CHINET protocol.The susceptibility results were interpreted according to the breakpoints in the Clinical & Laboratory Standards Institute(CLSI)M100 document.Results A total of 241,549 nonduplicate Klebsiella strains were isolated from 2015 to 2021,including Klebsiella pneumoniae(88.0％),Klebsiella aerogenes(5.8％),Klebsiella oxytoca(5.7％),and other Klebsiella species(0.6％).Klebsiella strains were mainly isolated from respiratory tract(48.49±5.32)％.Internal medicine(22.79±3.28)％,surgery(17.98±3.10)％,and ICU(14.03±1.39)％were the top 3 departments where Klebsiella strains were most frequently isolated.K.pneumoniae isolates showed higher resistance rate to most antimicrobial agents compared to other Klebsiella species.Klebsiella isolates maintained low resistance rates to tigecycline and polymyxin B.ESBLs-producing K.pneumoniae and K.oxytoca strains showed higher resistance rates to all the antimicrobial agents tested compared to the corresponding ESBLs-nonproducing strains.The K.pneumoniae and carbapenem-resistant K.pneumoniae(CRKP)strains isolated from ICU patients demonstrated higher resistance rates to majority of the antimicrobial agents tested than the strains isolated from non-ICU patients.The CRKP strains isolated from adult patients had higher resistance rates to most of the antimicrobial agents tested than the corresponding CRKP strains isolated from paediatric patients.Conclusions The prevalence of carbapenem-resistant strains in Klebsiella isolates increased greatly from 2015 to 2021.However,the Klebsiella isolates remained highly susceptible to tigecycline and polymyxin B.Antimicrobial resistance surveillance should still be strengthened for Klebsiella strains.