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 investigate the significance of urinary 8-oxo-7, 8-dihydroguanosine(8-oxoGuo)in assessing the short-term prognosis of sepsis in frail elderly patients.Methods:We conducted a cross-sectional study involving 62 frail elderly patients diagnosed with sepsis who were admitted to the Emergency Intensive Care Unit(EICU)at Beijing Hospital between March 2021 and March 2022.Based on their 28-day prognosis, the patients were categorized into two groups: those who died and those who survived.Upon admission, we collected urine samples and clinical data from both groups.We employed isotope dilution high-performance liquid chromatography-mass spectrometry to measure the levels of the RNA oxidation marker 8-oxoGuo in the urine.Results:A total of 62 frail elderly patients[aged(85.1±6.3)years]diagnosed with sepsis were included in the study, comprising 36 patients in the 28-day mortality group and 26 patients in the survival group.Univariate analysis revealed that the survival group had significantly lower body temperature, blood calcitonin(PCT)levels, sequential organ failure assessment(SOFA)scores, and urinary 8-oxoGuo levels compared to the mortality group.Additionally, the survival group exhibited a higher mean arterial pressure(MAP)than the mortality group, with all differences reaching statistical significance(all P<0.05).Spearman correlation analysis indicated that urinary 8-oxoGuo levels were positively correlated with both PCT and SOFA scores in frail elderly sepsis patients( r=0.426, 0.768, both P<0.05).Furthermore, logistic regression analysis identified urinary 8-oxoGuo and SOFA as independent risk factors for 28-day mortality in this population( OR=1.936, 1.427; P=0.006, 0.002).The area under the receiver operating characteristic curve(AUC)for urinary 8-oxoGuo and SOFA in predicting the 28-day prognosis of frail elderly sepsis patients was 0.761 and 0.741, respectively, both demonstrating statistical significance(both P<0.001). Conclusions:Our findings suggest that urinary 8-oxoGuo possesses strong predictive value for the short-term prognosis of sepsis in this vulnerable population.

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 construct a diagnostic and prognostic model for malignant pleural effusion (MPE) in patients with non-M1b stage (AJCC 7th edition) non-small cell lung cancer (NSCLC) by machine learning. Methods Retrospective analysis was conducted on patients diagnosed with NSCLC in the Surveillance, Epidemiology, and End Results database from 2010 to 2015, excluding those in the M1b stage. Two sets of data were collected: data 1 (patients with non-M1b stage NSCLC, n=47 392) was used to construct the MPE diagnostic model; and data 2 (patients with M1a stage NSCLC and MPE, n=2 422) was used to construct a prognostic model. The Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to screen feature variables, with a training set and validation set ratio of 7:3. Models were built using eight machine learning algorithms, with evaluation metrics including accuracy, precision, recall, F1 score, area under the ROC curve (AUC), decision curve, calibration curve, and precision recall curve (PR), with ROC-AUC as the main evaluation metric. Results The incidence of MPE in patients with non-M1b stage NSCLC was 5.12%, and the 1-year survival rate of patients with MPE was 32.5%. LASSO regression identified nine diagnostic-related variables and 12 prognostic-related variables. The AUC values of the models constructed by eight machine learning algorithms all exceeded 0.70. The random forest model performed the best in the diagnostic model (training set AUC=0.908, validation set AUC=0.897), and the XGBoost model showed the best performance in the prognostic model (training set AUC=0.905, validation set AUC=0.875). Other evaluation indicators showed good results and balanced distribution. SHAP feature importance analysis showed that tumor size, lymph node metastasis, and histological type were important influencing factors for the occurrence of MPE, and chemotherapy intervention was the most remarkably prognostic factor. Conclusion The random forest diagnostic model constructed in this study can effectively predict the risk of MPE in patients with non-M1b stage NSCLC, and the XGBoost prognostic model can predict the prognosis of M1a-stage NSCLC patients with concurrent MPE.

Objective To investigate the association between the pattern of carotid artery calcification and the prognosis of patients with acute cerebral infarction after 3 months of treatment. Methods A total of 112 patients who were diagnosed with acute ischemic stroke （AIS） in our hospital from March 2021 to September 2022 were enrolled as subjects. CT angiography was performed within 24 hours after admission， and the carotid artery was assessed in terms of calcification pattern （no calcification， intimal calcification， and medial calcification） and calcification load （low and high calcification）. After 7 days of treatment， CT reexamination was performed to evaluate hemorrhagic transformation and infarct volume. The patients were followed up for 3 months， and according to the modified Rankin Scale （mRS） score， they were divided into good prognosis group （82 patients with an mRS score of <3 points） and poor prognosis group （30 patients with an mRS score of ≥3 points）. Results Compared with the good prognosis group， the poor prognosis group had a significantly higher proportion of patients with an age of ≥70 years， a mean systolic blood pressure of ≥165 mmHg， a fasting blood glucose level of ≥7.5 mmol/L， an NIHSS score of ≥12 on admission， intimal calcification， medial calcification， high calcification， hemorrhagic transformation， and an infarct volume of ≥50 mm3 （P<0.05）. The multivariate logistic regression analysis showed that NIHSS score ≥12 on admission， intimal calcification， hemorrhagic transformation， and infarct volume ≥50 mm3 were risk factors for poor prognosis （P<0.05）. Conclusion Intimal calcification of the carotid artery may be associated with the poor short-term prognosis of AIS patients， which can be used as a new noninvasive indicator for predicting prognosis.
Prognosis

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 investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective To explore the impact of irregular shape of head CT hematomas on postoperative re-bleeding and prognosis of patients with spontaneous intracerebral hemorrhage(ICH)who undergo craniotomy for hematoma evacuation.Methods We retrospectively enrolled consecutive patients with ICH who underwent craniotomy for hematoma evacuation in the Department of Neurosurgery of the Second People's Hospital of Guiyang Affiliated to Guizhou Medical University from January 2019 to June 2024.Baseline and clinical data were collected form the patients,including age,gender,smoking history,drinking history,hypertension,diabetes,history of anticoagulant use,admission systolic and diastolic blood pressure,admission National Institutes of Health stroke scale(NIHSS)score,Glasgow coma scale(GCS)score,time from onset to the first head CT,neutrophil-to-lymphocyte ratio(NLR),and platelet-to-lymphocyte ratio(PLR).Admission head CT scans were used to assess hematoma shape(regular or irregular),hematoma location(basal ganglia,lobar,multifocal),hematoma volume,perihematomal edema volume,the presence of midline shift,and intraventricular extension.Volume of the hematoma was assessed 2 days after surgery.Postoperative re-bleeding is defined as an increase in the volume of the hematoma by 12.5 ml compared to the previous postoperative CT scan within 2 weeks after surgery,or the reappearance of high-density areas in the focal area of the head CT scan during follow-up after complete hematoma clearance.Conduct patients follow-ups via telephone at 6 months postoperatively to assess their modified Rankin scale(mRS)scores.The sliding dichotomy method was applied to define prognosis based on the patients' baseline characteristics and disease severity.The prognostic score was calculated using formula:10 × admission GCS score-age-0.64 × admission hematoma volume.A prognostic score＞27.672 was considered potentially favorable,while a score ≤ 27.672 was considered potentially unfavorable.For patients with a potentially favorable prognosis,an mRS score of 0-2 was defined as a good outcome,and a score of 3-6 as a poor outcome.For those with a potentially unfavorable prognosis,an mRS score of 0-3 was defined as a good outcome,and a score of 4-6 as a poor outcome.In the comparison of baseline and clinical data between patients with regular and irregular hematoma shapes,factors with P＜0.05 were included in propensity score matching(PSM)to adjust for confounding variables.A 1∶1 matching was performed using the nearest neighbor method with a caliper value set to 0.25.Variables with statistically significant differences between groups after PSM matching were included in the multivariate Logistic regression analysis to identify influencing factors for postoperative re-bleeding and poor prognosis in ICH patients undergoing craniotomy hematoma evacuation.The predictive value of irregular hematoma shape for postoperative rebleeding and poor prognosis in ICH patients was analyzed using receiver operating characteristic(ROC)curve analysis.Results(1)A total of 440 ICH patients were enrolled,including 342 males and 98 females,aged from 20 to 84 years with a mean age of(56±12)years.Statistically significant differences were observed in baseline and clinical data between patients with regular and irregular hematoma shapes before PSM,including age,admission GCS score,NIHSS score,NLR,proportion of patients with hematoma rupture into ventricles,preoperative hematoma volume,proportion of patients with midline shift,preoperative volume of hematoma surrounding edema,proportion of patients with hematoma located in multiple sites,and postoperative 2-day hematoma volume(all P＜0.05).After propensity score matching of these factors,298 ICH patients were included in the statistical analysis,comprising 228 males and 70 females,with an age range of 20 to 84 years and a mean age of(57±12)years.Following PSM,no statistically significant differences were observed in the baseline and clinical characteristics between patients with irregular and regular hematoma shapes(all P＞0.05).(2)After propensity score matching,28 patients experienced postoperative re-bleeding while 270 did not.Significant differences were observed between the two groups in the following factors:proportion of patients with a history of anticoagulant use,admission PLR,NLR,irregular hematoma shape,and hematoma volume at 2 days after operation(all P＜0.05).No statistically significant differences were found in the remaining baseline and clinical characteristics(all P＞0.05).Using postoperative re-bleeding as the dependent variable and incorporating factors with P＜0.05 from the univariate analysis as independent variables,multivariate Logistic regression analysis identified irregular hematoma shape(OR,2.821,95％CI 1.142-6.968,P=0.025)and larger hematoma volume at 2 days post-operation(OR,1.062,95％CI 1.026-1.099,P＜0.01)as independent risk factors for re-bleeding following intracranial hematoma evacuation in ICH patients.ROC curve analysis demonstrated that irregular hematoma shape predicted postoperative re-bleeding with an area under the curve(AUC)of 0.62,showing a sensitivity of 71.4％and a specificity of 52.2％.(3)After propensity score matching,174 patients had poor prognosis while 124 had good prognosis.Significant intergroup differences were observed in age,admission GCS score,NIHSS score,irregular hematoma shape,proportion of patients with hematomas located in the basal ganglia and cerebral lobes,and hematoma volume at 2 days post-operation(all P＜0.05).No statistically significant differences were found in the remaining baseline and clinical characteristics(all P＞0.05).Using poor prognosis as the dependent variable and incorporating factors with P＜0.05 from univariate analysis as independent variables,multivariate Logistic regression analysis revealed that advanced age(OR,1.039,95％CI 1.015-1.064,P=0.002),high admission NIHSS score(OR,1.068,95％CI 1.025-1.113,P=0.002),irregular hematoma shape(OR,2.675,95％CI 1.582-4.524,P＜0.01),and larger hematoma volume at 2 days post-operation(OR,1.033,95％CI 1.002-1.064,P=0.038)were independent risk factors for poor prognosis.Conversely,lobar hematoma location(OR,0.192,95％CI 0.073-0.504,P＜0.01)was identified as a protective factor.ROC curve analysis showed that irregular hematoma shape predicted poor prognosis after intracranial hematoma evacuation with an AUC of 0.61,demonstrating a sensitivity of 59.2％and specificity of 62.9％.Conclusion Irregular hematoma shape on head CT is an independent risk factor for both postoperative re-bleeding and poor prognosis in ICH patients undergoing craniotomy for hematoma evacuation.