Background Chronic intermittent hypobaric hypoxia (CIHH) can effectively alleviate type 2 diabetes mellitus (T2DM). In this process, the underlying mechanism in its association with the epigenetic regulation of DNA methylation in the promoter regions of glucose metabolism key enzyme genes remains unclear yet. Objective To investigate the effects of CIHH on expression and promoter region methylation of key enzyme genes related to glucose metabolism in diabetes mice, and to explore the underlying mechanism by which CIHH regulates glucose metabolism. Methods Forty C57BL/6J male mice were divided randomly into a normobaric normoxic control (NN/CON) group, a chronic intermittent hypobaric hypoxia intervention control (CIHH/CON) group, a normobaric normoxic diabetic model (NN/DM) group, and a chronic intermittent hypobaric hypoxia intervention diabetic model (CIHH/DM) group. The mice in the NN/DM and the CIHH/DM groups were fed for 7 weeks with high-fat and high-sugar diet. Subsequently, these mice were intraperitoneally injected consecutively with 50 mmol·L⁻¹ streptozotocin (STZ) for 5 d at a dose of 40 mg·kg⁻¹ (body weight) per day to create T2DM model mice. The mice in the CIHH/DM and the CIHH/CON groups were intervened by simulating hypobaric hypoxia at 5000 m altitude for 6 h per day, while the mice in the NN/DM and the NN/CON groups were always placed in a normobaric normoxic environment. All mice were continuously treated for 4 weeks, and blood glucose were monitored during this period. After the CIHH intervention experiment, the glucose tolerance and insulin sensitivity of mice were evaluated. A set of indicators involved in key glycolytic enzymes glucokinase (GK) and pyruvate kinase (PK), as well as key gluconeogenic enzymes phosphoenolpyruvate carboxyl kinase (PEPCK) and glucose-6-phosphatase (G6P) were measured in the liver of mice, including enzyme activity, relative mRNA expression level, and DNA methylation level in the gene promoter regions. Results Compared with the mice in the NN/DM group, the blood glucose levels of the mice in the CIHH/DM group decreased after the 25^th day of the CIHH intervention (P<0.05). Regarding the diabetic glucose tolerance curves, the area under the curve (AUC) of the mice in the CIHH/DM group was lower than that of the NN/DM group (P<0.05). Compared with the mice in the NN/DM group, the mice in the CIHH/DM group showed that the serum insulin content and HOMA of insulin resistance index (HOMA-IRI) decreased (P<0.05), the enzyme activities of GK and PK increased and the relative mRNA expression levels of their genes were up-regulated (P<0.05), while the enzyme activities of PEPCK and G6P decreased and the relative mRNA expression levels of their genes were down-regulated (P<0.05) in liver. The average DNA methylation levels in the promoter regions of GK, PK, PEPCK, and G6P genes in liver of mice in each group were not significantly different (P>0.05), and their correlations with mRNA expression levels were also not statistically significant (P>0.05). Conclusion CIHH intervention may reduce blood glucose level, improve glucose tolerance, alleviate insulin resistance, and regulate the key enzyme activities of glucose metabolism and the relative mRNA expression of their corresponding genes in T2DM mice, but the above phenomena are not related to the DNA methylation levels in the promoter regions of these key enzymes.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

AIM To determine the contents of aspartic acid,glutamic acid,serine,glycine,threonine,citrulline,arginine,alanine,γ-amino-butyric acid,tyrosine,valine,phenlalanine,isoleucine,ornithine,leucine,lysine and proline in Gualoupi Injection and its intermediates,and to analyze their change laws.METHODS The OPA-FMOC online derivatization analysis was performed on a 45℃ thermostatic Waters XBridge C18 column(4.6 mm×100 mm,3.5 μm),with the mobile phase comprising of phosphate buffer solution-[methanol-acetonitrile-water(45 : 45 : 10)]flowing at 1 mL/min in a gradient elution manner,and the detection wavelengths were set at 262,338 nm.Principal component analysis and heatmap analysis were adopted in chemical pattern recognition for the corresponding intermediates in ten processes of six batches of samples.RESULTS Seventeen amino acids showed good linear relationships within their own ranges(R2>0.998 0),whose average recoveries were 83.4％-119.5％with the RSDs of 0.91％-7.94％.Different batches of samples in the same process were clustered,and the corresponding intermediates in different processed were clustered into three groups.Alcohol precipitation and cation exchange column demonstrated the biggest influences on amino acid composition.CONCLUSION This experiment can provide important references for the critical factors on quality control of Gualoupi Injection,thus ensure the stability and uniformity of final product.

Objective To explore the clinical application value of simple resection in the treatment of pancreatic solid pseudopapillary tumor(SPT).Methods Retrospective analysis of clinical and follow-up data of pancreatic SPT patients who underwent simple pancreatectomy and conventional pancreatectomy from January 2015 to December 2022 in the pancreatic cystic tumor database of Huashan Hospital,Fudan University.A total of 87 patients with pancreatic SPT,including 14 cases underwent simple resection and 73 cases underwent conventional resection,were included.The average age was(36.2±11.7)years old,and females accounting for 87.4％.Results The accuracy of preoperative imaging diagnosis reached 88.5％.Simple resection had a significant advantage over conventional resection in terms of surgical time[(138.3± 56.4)min vs.(241.2±89.2)min,P＜0.05].Simple resection was not inferior to conventional resection in terms of common postoperative complications.Out of 87 cases,only 3 patients in conventional resection group experienced postoperative recurrence and metastasis,and all recurrent patients were still alive.There was no statistically significant difference in postoperative pancreatic endocrine and exocrine dysfunction,and quality of life between simple resection group and conventional resection group.Conclusions Simple resection of pancreatic SPT is reasonable and feasible,but the risks in actual clinical work cannot be ignored.Therefore,selective simple resection of SPT has certain clinical application value.

Objective To develop a low-oxygen mixed gas generator to make up for the deficiencies of low-pressure chambers and load-resistant hypoxia trainers during pilot hypoxia tolerance testing.Methods The device prepared the low-oxygen gas with the principle of gas separation,which was composed of a Sunsource OLF1100D-220AF air compressor,a SMC IDG75SAM4-03 filter,a buffer tank,an AIR Products PA3010 integrated assembly,a control box,sensors and regulators.The sensors included the pressure sensor,flow sensor,concentration sensor and dew point temperature sensor,and the control box consisted of a main control board,a power supply module,a transmission module,a communication module,a display and a housing.The embedded control software of the device was developed with KEIL 5 and C++.Results The device developed prepared the low-oxygen gas with the volume fraction being 4％to 18％and the maximum error of volume fraction being 0.05％,and the main components of the prepared gas met the technical requirements of medical oxygen as stipulated in GB 8982-2009 Oxygen supplies for medicine and aircraft breathing.Conclusion The low-oxygen gas prepared by the device has its volume fraction precisely controlled and can be used for hypoxia tolerance testing and acclimation training for pilots.[Chinese Medical Equipment Journal,2024,45(7):24-28]

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 investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

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.