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 effect of rapid maxillary expansion(RME)on sagittal soft and hard maxillofacial tissue in growing children.Methods In this retrospective study,children aged 6-12 years treated in Shanghai Stomatology Hospital from Jan 2018 to Dec 2020 were employed as subjects.Of the subjects,40 patients treated with RME were as the experimental group,27 patients presenting individualized malocclusion were as the control group.Lateral cephalogram was taken before(T0)and 2 years after treatment(T1).The images were imported into Dolphin Imaging's cephalometric measurement software,and the results were statistically analyzed using SPSS 22.0 software.Results Statistically significant differences were observed in all measurements before and after treatment in both two groups.A comparative analysis revealed that SNB value increased and ANB value decreased in the experimental group after treatment,while the changes in the control group were significantly smaller than those in the experimental group(P<0.05),indicating that RME is beneficial to the growth and development of mandibular in sagittal direction.Among the dentoalveolar measurements,statistically significant differences(P<0.01)were observed in U1-SN(upper incisor to sella-nasion angle),U1-NA(upper incisor to nasion-A point angle),U1-APog(upper incisor to A point-pogonion line distance),and overjet between the two groups.These findings indicate that RME significantly reduces the inclination of the maxillary central incisors,while having no significant effect on the mandibular central incisors.Compared with the control group,RME significantly reduced upper lip prominence,lip space and upper central incisor exposure(P<0.05),but had no effect on nose,chin and their correlation.Conclusion RME not only improved the prominence of the upper teeth and upper lip,but also facilitate the sagittal growth of mandibular in growing children.

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 analyze the CT manifestations of high altitude pulmonary edema(HAPE)to provide radiological evidence for its early and accurate diagnosis.Methods Totally 200 HAPE patients clinically confirmed at some hospital from April 2021 to April 2024 were enrolled into a study group,and 56 individuals undergoing health examinations at the hospital's physical examination center between January and June 2023 were included into a control group.Examinations were carried out with a United Imaging uCT528 40-slice spiral CT scanner.The patients in the study group were observed in terms of HAPE staging,the extent of pulmonary involvement,CT manifestations of different stages including location,distribution,density and morphology of pulmonary lesion.The diameters of the main pulmonary arteries and ascending aortas of the subjects in the two groups were measured,and the ratios of the two diameters were calculated.SPSS 25.0 software was used for statistical analysis.Results In the study group,there were 26 cases(13.0%)at early stage,105 ones at progression stage(52.5%),32 ones at critical outbreak stage(16.0%)and 37 ones at resolution and absorption stage(18.5%),and there were 35.5%with unilateral lung involvement and 64.5%with bilateral involvement.At early stage,HAPE chest CT manifestations included increased and thickened bilateral bronchovascular bundles,widened main pulmonary artery lumen and faint ground-glass opacity in lungs;at progression stage,HAPE chest CT manifestations revealed multiple cloud-like or patchy areas of increased density within lungs;at critical outbreak stage,CT scanning indicated diffuse patchy opacities and consolidation in lungs,white lung-like changes could be found in some severe cases,and bronchial air signs were shown within affected segments in some ones with severer signs in the right lung than in the left lung;at resolution and absorption stage the CT manifestations were similar to those at early stage,with lesions completely resolving after treatment.The study group had the diameters of the main pulmonary arteries greater while the diameters of the ascending aortas less than those of the control group,and the ratios of the diameters of the two diameters in the study group were higher than those in the control group,with the differences being statistically significant(all P<0.05).Conclusion Chest CT is an important examination method for the early diagnosis of HAPE and clarification of its clinical staging,which directly reflects the pulmonary pathological changes in HAPE patients and helps doctors fully understand the disease progression.

Objective:To establish a method for determination of fluoride in water using a fully automated biochemical analyzer (abbreviated as this method).Methods:Based on the parameters of the fully automatic biochemical analyzer, appropriate reagent volumes and reaction time were optimized to determine fluoride ions in water within the standard curve range (0.0 - 2.0 mg/L). The method was validated through evaluation of linear range, detection limit, precision, accuracy, and comparative analysis with the manual measurement results of fluoride reagent spectrophotometric method specified in the "Standard Examination Methods for Drinking Water - Part 5: Inorganic Nonmetallic indices" (GB/T 5750.5-2023).Results:Within the range of 0.0 - 2.0 mg/L fluoride mass concentration, the absolute values of the correlation coefficients were > 0.999 0 and the detection limit of this method was 0.082 mg/L. The relative standard deviation for the determination of fluoride level in water samples with low, medium and high fluoride mass concentrations was 4.03%, 2.16% and 1.68%, respectively. The spiked recovery rates were 98.1%, 99.5%, and 100.2%, respectively. There was no statistically significant difference between the results obtained by this method and manual measurement ( t = 1.07, P = 0.295). Conclusion:This method exhibits high sensitivity, accuracy, and efficiency in detecting fluoride, enabling rapid sample detection through instrumental automation instead of manual operation.

Objective:To investigate the efficacy of preoperative ultrasound-guided injection of carbon nanoparticle suspension in cervical lymph node dissection for thyroid cancer reoperation.Methods:Ninety-four patients undergoing reoperation for thyroid cancer admitted by the same physician team of the Department of Thyroid and Breast Surgery of the Ninety-sixty Hospital of the People’s Liberation Army (PLA) from Jan. 2019 to Sep. 2024 were retrospectively analyzed. According to the different scope of the initial surgery, they were divided into the re-specification clearance group, the regional lymph node clearance group, and the metastatic lymph node dissection group, and the groups were subdivided into the carbon nanoparticle group and the control group according to whether they were injected with carbon nanoparticle before the surgery or not. The t-test, χ2-test, and non-parametric test were used to compare the age, gender, surgical method, duration of surgery, total number of lymph nodes detected, and positive lymph node detection rate between the nano-charcoal group and the control group in the three groups. Results:There was no statistically significant difference between the three groups in terms of age, gender, surgical methods, or the total number of lymph nodes detected (all P>0.05) , and the difference between the surgical time of the carbon nanoparticle group in the re-regulation clearance group and the control group was not statistically significant ( P>0.05) ; the surgical time of the carbon nanoparticle group was shorter than that of the control group in both the regional lymph node clearance and the metastatic lymph node dissection groups, and the difference was statistically significant (all P<0.05) ; the positive detection rate of lymph nodes in the carbon nanoparticle group was higher than that in the control group among the three groups, and the difference was statistically significant (all P<0.05) . Conclusion:In the operation of cervical lymph node dissection for papillary thyroid cancer, preoperative ultrasound-guided injection of carbon nanoparticle can accurately localize the lymph nodes, increase the positive detection rate of lymph nodes, reduce the difficulty of surgical operation, and shorten the operation time.

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 analyze the CT manifestations of high altitude pulmonary edema(HAPE)to provide radiological evidence for its early and accurate diagnosis.Methods Totally 200 HAPE patients clinically confirmed at some hospital from April 2021 to April 2024 were enrolled into a study group,and 56 individuals undergoing health examinations at the hospital's physical examination center between January and June 2023 were included into a control group.Examinations were carried out with a United Imaging uCT528 40-slice spiral CT scanner.The patients in the study group were observed in terms of HAPE staging,the extent of pulmonary involvement,CT manifestations of different stages including location,distribution,density and morphology of pulmonary lesion.The diameters of the main pulmonary arteries and ascending aortas of the subjects in the two groups were measured,and the ratios of the two diameters were calculated.SPSS 25.0 software was used for statistical analysis.Results In the study group,there were 26 cases(13.0%)at early stage,105 ones at progression stage(52.5%),32 ones at critical outbreak stage(16.0%)and 37 ones at resolution and absorption stage(18.5%),and there were 35.5%with unilateral lung involvement and 64.5%with bilateral involvement.At early stage,HAPE chest CT manifestations included increased and thickened bilateral bronchovascular bundles,widened main pulmonary artery lumen and faint ground-glass opacity in lungs;at progression stage,HAPE chest CT manifestations revealed multiple cloud-like or patchy areas of increased density within lungs;at critical outbreak stage,CT scanning indicated diffuse patchy opacities and consolidation in lungs,white lung-like changes could be found in some severe cases,and bronchial air signs were shown within affected segments in some ones with severer signs in the right lung than in the left lung;at resolution and absorption stage the CT manifestations were similar to those at early stage,with lesions completely resolving after treatment.The study group had the diameters of the main pulmonary arteries greater while the diameters of the ascending aortas less than those of the control group,and the ratios of the diameters of the two diameters in the study group were higher than those in the control group,with the differences being statistically significant(all P<0.05).Conclusion Chest CT is an important examination method for the early diagnosis of HAPE and clarification of its clinical staging,which directly reflects the pulmonary pathological changes in HAPE patients and helps doctors fully understand the disease progression.

Objective:To establish a method for determination of fluoride in water using a fully automated biochemical analyzer (abbreviated as this method).Methods:Based on the parameters of the fully automatic biochemical analyzer, appropriate reagent volumes and reaction time were optimized to determine fluoride ions in water within the standard curve range (0.0 - 2.0 mg/L). The method was validated through evaluation of linear range, detection limit, precision, accuracy, and comparative analysis with the manual measurement results of fluoride reagent spectrophotometric method specified in the "Standard Examination Methods for Drinking Water - Part 5: Inorganic Nonmetallic indices" (GB/T 5750.5-2023).Results:Within the range of 0.0 - 2.0 mg/L fluoride mass concentration, the absolute values of the correlation coefficients were > 0.999 0 and the detection limit of this method was 0.082 mg/L. The relative standard deviation for the determination of fluoride level in water samples with low, medium and high fluoride mass concentrations was 4.03%, 2.16% and 1.68%, respectively. The spiked recovery rates were 98.1%, 99.5%, and 100.2%, respectively. There was no statistically significant difference between the results obtained by this method and manual measurement ( t = 1.07, P = 0.295). Conclusion:This method exhibits high sensitivity, accuracy, and efficiency in detecting fluoride, enabling rapid sample detection through instrumental automation instead of manual operation.