Polymyxins,a class of cyclic peptide antibiotics,have become the last line of defense against gram-negative bacterial infections as the number of multidrug-resistant bacteria continues to rise.Het-eroresistance refers to the presence of subpopulations within the same strain with varying sensitivities to antibi-otics,which cannot be detected by standard clinical tests and may result in treatment failure.In several com-mon gram-negative bacteria,mutations in the PhoPQ and PmrAB two-component systems are key contributors to polymyxin heteroresistance.This review aims to summarize recent research on the mechanisms of polymyxin heteroresistance in gram-negative bacteria,so as to provide insights for developing rapid detection methods and improving clinical treatment strategies.

Objective To investigate the application effect of a refined early diet plan in patients with distal gastric cancer after laparoscopic radical surgery.Methods By convenience sampling method,46 patients with laparoscopic radical gastrectomy for distal gastric cancer admitted to a tertiary hospital in Zhejiang Province from July to December 2023 were selected as an experimental group,while 49 patients admitted from January to June 2023 as a control group.The experimental group was administered with the refined early diet plan,and the control group was administered with conventional methods.The intervention period was from the first day after surgery to discharge.The differences of the first postoperative defecation time,perioperative thirst and hunger score,postoperative hospitalization time,hospitalization cost,postoperative complications and the incidence of readmission 30 days after surgery were compared between the 2 groups.Results 42 patients in the experimental group and 49 patients in the control group completed the study.First postoperative exhaust time(t=4.922,P＜0.001),first postopera-tive defecation time(Z=-2.440,P=0.015),perioperative thirst score(Z=-8.024,P＜0.001),perioperative hunger score(Z=-8.192,P＜0.00 1),postoperative hospitalization time(Z=-7.622,P＜0.001)and hospitalization cost(Z=-4.522,P＜0.001)were lower than those of the control group,and the difference was statistically significant.There was no significant difference in complication rate and 30-day readmission rate between the experimental group and the control group(P＞0.05).Conclusion The refined early diet plan is safe and effective for early recovery of patients after laparoscopic radical gastrectomy for distal gastric cancer,promoting intestinal function recovery,shortening hospital stay,reducing hospital costs,and improving patients'subjective comfort.

Objective To discuss the different types of benefits of family care for Alzheimer's disease(AD)and its influencing factors based on the latent profile analysis.Methods A total of 154 family caregivers of patients with AD who were treated in Shaoxing Seventh People's Hospital,from July 2020 to September 2023 were selected as the research objects.A cross-sectional survey was conducted on the family caregivers of patients with AD by using general information questionnaire and disease benefit scale,and the results were profile analyzed.The influencing factors of family caregivers of patients with AD were analyzed by multiple linear regression.Results Family caregivers of AD can be roughly divided into three potential profile categories:high support positive type,stable health type and low growth introversion type.Multiple linear regression analysis showed that age,family income per capita,anxiety and social support were the independent influencing factors of family caregivers of AD(P＜0.05).Conclusion There are characteristic differences in the types of disease benefit of family caregivers of AD.Nurses can take personalized psychological counseling and intervention measures according to different types of disease benefit of family caregivers to maintain the mental health of family caregivers of AD.

Objective To summarize the changing prevalence of carbapenem resistance in Enterobacterales based on the data of CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021 for improving antimicrobial treatment in clinical practice.Methods Antimicrobial susceptibility testing was performed using a commercial automated susceptibility testing system according to the unified CHINET protocol.The results were interpreted according to the breakpoints of the Clinical & Laboratory Standards Institute(CLSI)M100 31st ed in 2021.Results Over the seven-year period(2015-2021),the overall prevalence of carbapenem-resistant Enterobacterales(CRE)was 9.43％(62 342/661 235).The prevalence of CRE strains in Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae was 22.38％,9.73％,and 8.47％,respectively.The prevalence of CRE strains in Escherichia coli was 1.99％.A few CRE strains were also identified in Salmonella and Shigella.The CRE strains were mainly isolated from respiratory specimens(44.23±2.80)％,followed by blood(20.88±3.40)％and urine(18.40±3.45)％.Intensive care units(ICUs)were the major source of the CRE strains(27.43±5.20)％.CRE strains were resistant to all the β-lactam antibiotics tested and most non-β-lactam antimicrobial agents.The CRE strains were relatively susceptible to tigecycline and polymyxins with low resistance rates.Conclusions The prevalence of CRE strains was increasing from 2015 to 2021.CRE strains were highly resistant to most of the antibacterial drugs used in clinical practice.Clinicians should prescribe antimicrobial agents rationally.Hospitals should strengthen antibiotic stewardship in key clinical settings such as ICUs,and take effective infection control measures to curb CRE outbreak and epidemic in hospitals.

Objective To characterize the changing species distribution and antibiotic resistance profiles of respiratory isolates in hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Commercial automated antimicrobial susceptibility testing systems and disk diffusion method were used to test the susceptibility of respiratory bacterial isolates to antimicrobial agents following the standardized technical protocol established by the CHINET program.Results A total of 589 746 respiratory isolates were collected from 2015 to 2021.Overall,82.6％of the isolates were Gram-negative bacteria and 17.4％were Gram-positive bacteria.The bacterial isolates from outpatients and inpatients accounted for(6.0±0.9)％and(94.0±0.1)％,respectively.The top microorganisms were Klebsiella spp.,Acinetobacter spp.,Pseudomonas aeruginosa,Staphylococcus aureus,Haemophilus spp.,Stenotrophomonas maltophilia,Escherichia coli,and Streptococcus pneumoniae.Each microorganism was isolated from significantly more males than from females(P＜0.05).The overall prevalence of methicillin-resistant S.aureus(MRSA)was 39.9％.The prevalence of penicillin-resistant S.pneumoniae was 1.4％.The prevalence of extended-spectrum β-lactamase(ESBL)-producing E.coli and K.pneumoniae was 67.8％and 41.3％,respectively.The overall prevalence of carbapenem-resistant E.coli,K.pneumoniae,Enterobacter cloacae,Pseudomonas aeruginosa,and Acinetobacter baumannii was 3.7％,20.8％,9.4％,29.8％,and 73.3％,respectively.The prevalence of β-lactamase was 96.1％in Moraxella catarrhalis and 60.0％in Haemophilus influenzae.The H.influenzae isolates from children(＜18 years)showed significantly higher resistance rates to β-lactam antibiotics than the isolates from adults(P＜0.05).Conclusions Gram-negative bacteria are still predominant in respiratory isolates associated with serious antibiotic resistance.Antimicrobial resistance surveillance should be strengthened in clinical practice to support accurate etiological diagnosis and appropriate antimicrobial therapy based on antimicrobial susceptibility testing results.

Objective:To analyze the electrocardiogram (ECG) data of congenital long QT syndrome (LQTS) patients, and to identify the ECG parameters for prediction of life-threatening arrhythmic events (LAEs).Methods:This cohort study enrolled patients diagnosed with congenital LQTS at the Department of Cardiology, Beijing Tsinghua Changgung Hospital from September 2014 to May 2023. Baseline clinical and ECG data were collected. Patients were followed with LAEs as the primary endpoint. Based on the occurrence of LAEs, patients were divided into two groups: the event group and the event-free group. Cox regression analysis was used to identify independent predictors of LAEs in LQTS patients.Results:A total of 293 patients diagnosed with congenital LQTS were included, aged 32.5 (19.0, 41.8) years, including 201 females (68.6%). Sixty-six patients experienced LAEs and 227 patients did not. Compared to the event-free group, the event group had a younger onset age (13.0 (5.5, 20.5) years vs. 26.0 (13.0, 35.0) years), a slower heart rate (69.0 (59.5, 76.5) beats/min vs. 77.0 (67.0, 88.0) beats/min), a higher proportion with family history of sudden cardiac death (30.3% vs. 14.5%), as well as longer QT intervals (500.0 (467.0, 594.0) ms vs. 428.0 (402.0, 470.0) ms) and QTc intervals (544.0 (502.5, 589.0) ms vs. 489.0 (480.0, 504.0) ms). Additionally, the event group had higher peak T-wave alternans value (65.0 (42.5, 85.3) μV vs. 44.0 (36.0, 54.0) μV), a higher proportion of patients with documented torsades de pointes (TdP) or ventricular fibrillation (VF) on 24-hour Holter monitoring (39.3% vs. 4.9%), and higher rates of pharmacological treatment (100.0% vs. 9.7%) and device therapy or left cardiac sympathetic denervation (45.5% vs. 2.2%) (all P<0.05). Multivariate Cox regression analysis identified that the heart rate<60 beats/min ( HR=2.0, 95% CI: 1.0-3.7) and QTc interval ≥500 ms ( HR=2.9, 95% CI: 1.5-5.6) on 12-lead ECG, as well as peak T-wave alternans value ≥55.5 μV ( HR=3.2, 95% CI: 1.3-7.8) and documented TdP or VF ( HR=2.0, 95% CI: 1.1-3.7) on 24-hour Holter monitoring were independent predictors of LAEs in LQTS patients (all P<0.05). Conclusion:Heart rate <60 beats/min and QTc interval ≥500 ms on 12-lead ECG, along with peak T-wave alternans value ≥55.5 μV and documented TdP or VF on 24-hour Holter monitoring, have been identified as independent predictors of LAEs in patients with LQTS. These ECG parameters may serve as valuable early indicators of sudden cardiac death in LQTS patients.

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.

Infectious diseases caused by bacteria,viruses,and other pathogens are a significant global public health challenge.Accurate and efficient detection methods are crucial for the diagnosis and prevention of infec-tious diseases.Nucleic acid detection technologies based on the clustered regularly interspaced short palin-dromic repeats(CRISPR)and CRISPR-associated protein(Cas)systems have begun to be applied in the de-tection of pathogenic microorganisms due to their high sensitivity,high specificity,and rapid simplicity.In re-cent years,various convenient and efficient nucleic acid detection technologies and platforms for pathogenic microorganisms have been derived from the CRISPR/Cas system,further expanding the field of pathogen nu-cleic acid detection.This article summarizes the research progress of pathogen nucleic acid detection technolo-gies based on the CRISPR/Cas system,discusses the value of these detection technologies in the in vitro diag-nosis of pathogens,and provides references for the further development of CRISPR/Cas nucleic acid detection technologies.

Objective To analyze the main epidemiological characteristics of fungal infection in this hospital in the past 7 years,and to provide reference for clinical treatment and prevention and control strategies of fun-gal infection.Methods The fungal data and clinical data of related patients isolated from clinical samples in Peking Union Medical College Hospital from early January 2018 to the end of May 2024 were selected,and the main epidemiological characteristics of fungal infection in this hospital were identified and described through multi-angle statistical analysis.Results A total of 4 479 patients with filamentous fungal infection were en-rolled.The proportion of male patients[57.5％(2 576/4 479)]was higher than that of female patients[42.5％(1 903/4 143)],mainly distributed in internal medicine,Intensive Care Unit(ICU)and emergency de-partment,among which internal medicine accounted for the highest proportion[50.0％(2 241/4 479)].About 90.0％of the specimens were from the lower respiratory tract,in addition to specimens from skin and soft tis-sue,tissue,ear and blood culture.In terms of seasonal distribution,there are more patients in winter.The fun-gi were mainly composed of Aspergillus,Mucor,Cerdosporium,Fusarium and Penicillium,among which As-pergillus was the most abundant,accounting for 74.6％of the total.Aspergillus fumigatus was the most a-bundant Aspergillus,accounting for 42.5％of the total Aspergillus(1 418/3 340).Among the related infec-tions caused by mold,Aspergillus was the most common in the lower respiratory tract,accounting for 76.8％.Among them,Aspergillus fumigatus accounted for the highest proportion(33.6％).98.6％of the molds infected the ear were Aspergillus,of which Aspergillus niger and Aspergillus terreus were the most common.Skin infections are mainly caused by Sporothrix schenckii,Trichophyton rubrum,Microsporum ca-nis.The results of in vitro drug sensitivity test showed that the four common Aspergillus isolated in this hos-pital were sensitive to voriconazole,and amphotericin B had better antifungal activity against Mucorales in vitro.Conclusion Based on the main epidemiological characteristics of fungal infections in this hospital,it is recommended that special attention be paid to the admission of patients in the respiratory department during the peak infection period in autumn and winter.In the treatment of fungal infections in different regions and on different body parts,attention should be paid to the differences in the distribution of bacterial species.