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.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective:To assess the effect of transversus abdominis plane block (TAPB) with liposomal bupivacaine and general anesthesia on postoperative delirium (POD) in elderly patients with prior novel coronavirus pneumonia (COVID-19).Methods:In this randomized double-blind controlled study, 416 patients of either sex, aged 65-90 yr, weighing 50-90 kg, of American Society of Anesthesiologists Physical Status classification Ⅰ-Ⅲ, diagnosed as having COVID-19 within 6 months prior to surgery, who underwent laparoscopic colorectal cancer surgery under combination of elective TAPB and combined intravenous-inhalational general anaesthesia at Qingdao Municipal Hospital from June 2023 to December 2024, were selected. The patients were divided into liposomal bupivacaine group ( n=208) and bupivacaine hydrochloride group ( n=208) using the random number table method. After induction of anaesthesia, bilateral TAPB was performed with liposomal bupivacaine injectio 266 mg (40 ml) in liposomal bupivacaine group and with 0.5% bupivacaine hydrochloride 40 ml in bupivacaine hydrochloride group. The primary outcome measure was the occurrence of POD within 7 days after surgery. Secondary outcome measures included severity of POD, pain scores at 24, 48 and 72 h after operation, the rate of postoperative rescue analgesia and consumption of morphine, duration of post-anesthesia care unit stay, and length of hospital stay. The occurrence of complications such as death, reoperation, atelectasis and pneumonia was recorded at 30 days after surgery. Results:Compared with bupivacaine hydrochloride group, the incidence of POD was significantly decreased (21.5% [43/200]versus 12.0% [24/200]), pain scores at 24, 48 and 72 h after operation were decreased, the rate of postoperative rescue analgesia and consumption of morphine were decreased, and the duration of post-anesthesia care unit stay and length of hospital stay were shortened in liposomal bupivacaine group ( P<0.05). There was no significant difference in the severity of POD and the case fatality rate and related complications within 30 days after surgery between the two groups ( P>0.05). Conclusions:Liposomal bupivacaine TAPB combined with general anesthesia can reduce the development of POD in elderly patients with prior COVID-19.

Objective:To evaluate the relationship between preoperative concentrations of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:Six hundred and twenty-five patients of either sex, aged 50-90 yr, weighing 50-80 kg, with American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ, with the preoperative Mini-Mental State Examination score > 23, who underwent elective knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital from January 2022 to December 2023, were selected. The CSF specimens 2 ml were withdrawn from the subarachnoid space after successful subarachnoid puncture for determination of the concentrations of sTREM2, Amyloid beta protein (Aβ 42), total tau protein (T-tau), and phosphorylated tau protein (p-tau) by enzyme-linked immunosorbent assay. POD was assessed using the Confusion Assessment Method. Patients were divided into POD group and non-POD group based on whether POD occurred. Logistic regression was used to identify the risk and protective factors for POD. The performance of CSF sTREM2 concentration combined with CSF biomarker levels in predicting POD was evaluated using the receiver operating characteristic (ROC) curve and clinical decision curve. The mediating effect of CSF biomarker concentrations in the relationship between CSF sTREM2 concentration and POD was analyzed. Results:Five hundred and nineteen patients were finally included, with 112 patients in POD group and 407 patients in non-POD group. The results of logistic regression analysis showed that the elevated preoperative sTREM2 concentration in CSF was the risk factor for POD after adjusting for multiple confounding factors such as age, sex, body mass index, years of education, Mini-Mental State Examination score, history of smoking, history of drinking, hypertension, diabetes mellitus and coronary heart disease. The area under the ROC curve of the preoperative sTREM2 concentration in CSF in predicting POD was 0.716, and the area under the ROC curve of the preoperative sTREM2 concentration in CSF combined with CSF biomarkers in predicting POD was 0.796. This model had high clinical application value and predictive efficacy. The relationship between the preoperative sTREM2 concentration in CSF and POD was partially mediated by the CSF p-tau concentration (proportion of mediated effect 24.67%) and t-tau protein concentration (proportion of mediated effect 17.33%).Conclusions:The elevated preoperative concentration of sTREM2 in CSF is a risk factor for POD in patients undergoing total knee/hip arthroplasty, and concentrations of t-tau and p-tau in CSF play a mediating role in the relationship between the preoperative CSF sTREM2 concentration and POD.

Objective:To evaluate the association between postoperative delirium (POD) and preoperative frailty in elderly patients undergoing knee or hip arthroplasty.Methods:This nested case-control study utilized medical records from elderly patients who underwent knee or hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between September 2021 and May 2023. Participants were divided into 2 groups based on clinically diagnosed POD: POD group ( n=53) and non-POD group ( n=256). Univariate analysis was conducted on suspected influencing factors, and logistic regression analysis was utilized to identify the risk factors for POD. Receiver operating characteristic and clinical decision curves were plotted to evaluate the predictive performance of these risk factors for POD. Mediation analysis was performed, and a clinically applicable nomogram was constructed to achieve visual prediction of outcomes. Results:There were statistically significant differences in age, preoperative frailty, body mass index, American Society of Anesthesiologists Physical Status classification, Memorial Delirium Assessment Scale scores, and concentrations of Aβ 42, Aβ 40, phosphorylated tau protein (p-tau protein) and tau protein, Aβ 42/tau ratio and Aβ 42/p-tau ratio in cerebrospinal fluid (CSF) between non-POD group and POD group ( P<0.05). Preoperative frailty was a risk factor for POD ( P<0.05). Mediation analysis revealed that the association between preoperative frailty and POD was mediated by CSF tau protein concentrations. The area under the receiver operating characteristic curve of preoperative frailty and CSF biomarker concentrations in predicting POD was 0.974 ( P<0.05). The clinical decision curve demonstrated that the model combining the preoperative frailty and CSF biomarker concentrations predicted a higher net benefit ( P<0.05). The clinical decision curve showed that the model combining preoperative frailty and CSF biomarker concentrations predicted a higher net benefit. Conclusions:Preoperative frailty is a risk factor for POD in elderly patients undergoing knee or hip arthroplasty, and its combination with CSF biomarker concentrations can effectively predict the occurrence of POD. CSF tau concentration mediates the association between preoperative frailty and development of POD.

Objective:To evaluate the association between the preoperative aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:In this nested case-control study, medical records from patients, aged ≥55 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, with Mini-Mental State Examination (MMSE) scale score >24 on preoperative day 1, scheduled for elective total knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between November 2021 and December 2023, were collected. POD was assessed using the Confusion Assessment Method. Patients were categorized into POD and non-POD groups based on the occurrence of POD. Logistic regression was employed to identify protective and risk factors for POD. The predictive performance of preoperative AST/ALT ratio alone and its combination with cerebrospinal fluid (CSF) biomarker concentrations for POD was evaluated using receiver operating characteristic curves, and the clinical utility of the prediction models was assessed using decision curve analysis. Mediation analysis was conducted to examine the mediation role of CSF biomarkers in the relationship between the preoperative AST/ALT ratio and POD. Restricted cubic splines were used to assess the nonlinear relationship between the preoperative AST/ALT ratio and POD.Results:A total of 460 patients were finally included, with 49 in POD group and 411 in non-POD group. After adjustment for multiple confounding factors including age, sex, educational level, MMSE score, history of hypertension, history of diabetes, history of smoking and history of alcohol use, multivariable logistic regression identified that the higher preoperative AST/ALT ratio, CSF total tau protein (t-tau) and phosphorylated tau protein (p-tau) concentrations were independent risk factors for POD, whereas lower CSF β-amyloid 42 (Aβ 42) concentration, Aβ 42/t-tau ratio and Aβ 42/p-tau ratio served as protective factors ( P<0.05). The area under the receiver operating characteristic curve of the preoperative AST/ALT ratio combined with CSF biomarkers in predicting POD was 0.939 ( P<0.001), demonstrating high clinical efficacy. After adjusting for age, educational level, sex, MMSE score, history of hypertension, history of diabetes, history of smoking, history of alcohol use and body mass index, restricted cubic splines revealed a nonlinear relationship between preoperative AST/ALT levels and the probability of POD, and the probability of POD increased with rising ratios when the preoperative AST/ALT ratio ranged from 1.09 to 1.40 ( Poverall < 0.05, Pnonlinear <0.05). After stratification by sex, the preoperative AST/ALT ratio demonstrated a linear relationship with the probability of POD ( Poverall <0.05, Pnonlinear>0.05). Mediation analysis indicated that the relationship between the preoperative AST/ALT ratio and POD was partially mediated by CSF p-tau concentration (proportion mediated 18.1%), CSF t-tau concentration (proportion mediated 12.0%), and the Aβ 42/t-tau ratio (proportion mediated 15.4%). Conclusions:A higher preoperative AST/ALT ratio is an independent risk factor for POD in total knee/hip arthroplasty patients. The concentrations of CSF t-tau and p-tau and Aβ 42/t-tau ratio have a mediating role in the relationship between the preoperative AST/ALT ratio and POD.

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.