Objective:To identify the serotype and genotype characteristics of the first cluster infection of Brucella in Nujiang Lisu Autonomous Prefecture of Yunnan Province. Methods:The information of seven suspected cluster brucellosis cases reported in Lanping County, Nujiang Lisu Autonomous Prefecture in April 2023 were collected, blood samples were collected, and the strains were isolated and cultured. Serological methods were employed for brucellosis diagnosis, bacterial species identification was performed using BCSP31-PCR and AMOS-PCR. Multilocus locus variable-number tandem repeat analysis (MLVA) was conducted for strain genotyping, followed by phylogenetic analysis comparing the strains with those from other regions of China.Results:All seven cases were diagnosed with brucellosis, they were all villagers from the same village and had daily contact with sheeps. Four suspected Brucella strains were isolated, identified as Brucella melitensis biotype by BCSP31-PCR and AMOS-PCR. The four isolated strains exhibited identical MLVA-16 genotype, with MLVA-8 genotype 42 and MLVA-11 genotype 180, belonging to the Eastern Mediterranean lineage. Compared with the MLVA-16 of the isolated strains from other regions of China, the four isolated strains formed an independent cluster. Conclusion:The first cluster infection of Brucella in Nujiang Lisu Autonomous Prefecture of Yunnan Province is caused by Brucella melitensis biotype, and the four isolated strains have showed unique MLVA genotype.

Objective:To learn about the geographical distribution and bio-tying diversity characteristics of Brucella strains isolated in Yunnan Province. Methods:From March 2017 to December 2023, 516 suspected Brucella strains were collected from brucellosis surveillance sites and hospitals in Yunnan Province, and Yunnan Institute of Endemic Disease Control and Prevention. The Brucella isolates were confirmed to genus level by BCSP31-PCR, and subsequently identified to species and biovar level using conventional biotyping methods and AMOS-PCR. The geographical distribution of the strains was visualized using ArcGIS 10.8 software, simultaneously analyze the general characteristics of brucellosis patients. Results:Among the 516 suspected Brucella strains, 514 strains were isolated from patient blood samples and 2 strains were isolated from sheep blood samples. BCSP31-PCR identification showed that all strains were Brucella spp. The results of conventional biotyping and AMOS-PCR identification revealed that the isolates comprised 514 Brucella melitensis strains (16 strains of Brucella melitensis biovar 1 and 498 strains of Brucella melitensis biovar 3), one Brucella abortus (biovar 1) strain, and one Brucella canis strain. The strain was distributed in 69 counties/cities of 13 prefectures/cities in Yunnan Province, involving 390 administrative villages in 186 townships. Brucella melitensis was the dominant epidemic strain, and the largest number of Brucella melitensis was distributed in Kunming City( n = 205), followed by Honghe Hani and Yi Autonomous Prefecture ( n = 98) and Qujing City ( n = 72). Brucella abortus was only distributed in Lincang City ( n = 1), and Brucella canis was distributed Wenshan Zhuang and Miao Autonomous Prefecture ( n = 1). The age range of 514 brucellosis patients ranged from 10 months to 88 years, with the majority being between 40 and 60 years old (52.72%, 271/514). The predominant occupational group was farmers (89.11%, 458/514), followed by students (5.06%, 26/514). Conclusion:Brucella exhibits a wide distribution and species/biovar diversity in Yunnan Province, with infection among the farming population emerging as a serious public health problem in the area.

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 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 study the epidemiological characteristics and clinical diagnosis of human brucellosis in Qujing City, Yunnan Province.Methods:Through the Infectious Disease Reporting Information Management System of the China Disease Prevention and Control Information System, the basic information and clinical diagnostic data of brucellosis cases reported in Qujing City from January 2008 to December 2023 were retrospectively collected. Descriptive epidemiological methods were used to analyze the epidemic profile, three distribution characteristics (time, population, region), and diagnosis of brucellosis.Results:A total of 1 417 brucellosis cases were reported in Qujing City from 2008 to 2023, with no death. The annual average incidence of brucellosis was 1.49/100 000, with no cases reported in 2009 and 2010, and the highest incidence in 2023 (7.82/100 000). The incidence of brucellosis showed an increasing trend year by year (χ 2trend = 1 874.58, P < 0.001). The number of cases from June to November accounted for 61.54% (872/1 417). The majority of brucellosis cases were in the age group of 36 - 65 years old, accounting for 67.82% (961/1 417). Among them, there were 954 males and 463 females, with a gender ratio of 2.06 ∶ 1.00. Farmers were the main occupation, accounting for 84.33% (1 195/1 417). The cases were mainly distributed in Luliang County (621 cases), Xuanwei City (282 cases) and Shizong County (137 cases), accounting for 73.39% (1 040/1 417). The median interval between onset and diagnosis was 13 days, and the cases with intervals ≤7 d, 8 - 30 d, and ≥31 d accounted for 32.11% (455/1 417), 40.16% (569/1 417), and 27.73% (393/1 417), respectively. Totally 63.94% (906/1 417) of the cases were confirmed in medical institutions in Qujing City. Conclusions:The incidence of brucellosis in Qujing City is increasing year by year, with men, middle-aged and elderly people and farmers as the main population, summer and autumn as the peak period, and Luliang County, Xuanwei City and Shizong County as the high incidence areas. Most cases have an interval of less than 30 days between onset and diagnosis, and can be diagnosed within the jurisdiction.

Objective To investigate the mechanism by which Senegenin(SEN)alleviates microglial inflammatory response through the nuclear factor erythroid 2-related factor 2(Nrf2)/NOD-like receptor protein 3(NLRP3)pathway.Methods BV2 mouse microglia cells were randomly divided into control group,model group,SEN group and MCC950 group.Cells in control group were not treated,and cells in model group were added with 1 μg/ml lipopolysaccharide(LPS);Cells in SEN group were added with 1 μg/ml LPS+4 μmol/L SEN,and cells in MCC950 group were added with 1 μg/ml LPS+10 μmol/L MCC950 for 24 hours.CCK-8 method was used to detect the effect of different concentrations of SEN on the viability of BV2 cells.Griess method was used to determine the release amount of nitric oxide(NO)in the supernatant.Real-time fluorescent quantitative PCR was used to determine the mRNA expression levels of NLRP3,lymphocyte apoptosis-associated spect-like protein containing a CARD(ASC),caspase-1,interleukin(IL)-1β and IL-18 mRNA.Immunofluorescence staining was used to detect the expression levels of ASC,IL-1β,Nrf2 and heme oxygenase-1(HO-1).Western blotting was used to detect the expression levels of NLRP3,caspase-1,ASC,IL-1β,IL-18,Nrf2,HO-1,nuclear factor kappa B(NF-κB)and inducible nitric oxide synthase(iNOS).Results The results of CCK-8 method showed that there was no significant difference in the viability of BV2 cells treated with 2～20 μmol/L SEN compared with control group(P>0.05).Compared with control group,the viability of BV2 cells in model group decreased significantly(P<0.05).Compared with model group,the viability of BV2 cells in 4 μmol/L SEN group was significantly restored(P<0.05).Compared with control group,the results of Griess method showed that the release amount of NO in cells of model group increased significantly(P<0.05);the results of real-time PCR showed that the expression levels of NLRP3,ASC,caspase-1,IL-1β and IL-18 mRNA in cells of model group increased significantly(P<0.05);the results of Western blotting showed that the protein expression levels of NLRP3,ASC,caspase-1,IL-1β and IL-18 proteins in cells of model group increased significantly(P<0.05),and the immunofluorescence staining results showed that the expression levels of iNOS and NF-κB protein in cells of model group increased,and the expression levels of Nrf2 and HO-1 decreased,with statistically significant differences(P<0.05).Compared with model group,the release amount of NO in cells of SEN group and MCC950 group decreased,and the expression levels of NLRP3,ASC,caspase-1,IL-1β and IL-18 mRNA and proteins decreased,with statistically significant differences(P<0.05);in the SEN group,the expression levels of iNOS and NF-κB decreased,and immunofluorescence staining showed that Nrf2 was translocated into the nucleus,and the expression levels of Nrf2 and HO-1 proteins increased significantly,with statistically significant differences(P<0.05).Conclusions SEN could alleviate the inflammatory response of mouse microglia cells induced by LPS and inhibit the activation and expression of NLRP3 inflammasome,with an effect comparable to that of the inflammasome inhibitor MCC950.The mechanism may be related to the regulation of the expression of upstream factors Nrf2 and HO-1.

Objective To investigate the types and mechanisms of microglial cell death induced by interaction between palmitic acid(PA)and lipopolysaccharide(LPS).Methods BV-2 microglial cells were divided into three groups for apoptosis research,BSA group,PA treatment group,and staurosporine(STA)group.They were further divided into four groups for necrosis research,BSA group,BSA+inhibitor group,PA group,and PA+inhibitor group.Western blotting was conducted to assess the expression levels of key proteins involved in apoptosis and necrosis pathways.The effect of PA on microglial cells was validated through feeding a high-fat diet to Institute of Cancer Research(ICR)mice.Results Apoptotic microglia were observed in both BSA group and PA group,PA significantly induced the activation of caspase-3,caspase-7,and poly ADP-ribose polymerase(PARP).However,compared to the BSA group,the level of activated Caspase-7 in the STA group did not change significantly.Inhibition of ferroptosis,necroptosis,or autophagy did not protect against PA-induced cell damage,while the Caspase-11 inhibitor,wedelolactone(WE),significantly improved PA induced cell damage.This study also found that PA could promote LPS entry into microglial cells and induce pyroptosis.This phenomenon and the protective effect of WE were further confirmed in a high-fat diet mouse model through immunofluorescent staining and Western blotting.Conclusion PA induces apoptosis and pyroptosis in microglial cells,while simultaneously promoting LPS entry into microglial cells and inducing pyroptosis.

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 study the epidemiological characteristics and clinical diagnosis of human brucellosis in Qujing City, Yunnan Province.Methods:Through the Infectious Disease Reporting Information Management System of the China Disease Prevention and Control Information System, the basic information and clinical diagnostic data of brucellosis cases reported in Qujing City from January 2008 to December 2023 were retrospectively collected. Descriptive epidemiological methods were used to analyze the epidemic profile, three distribution characteristics (time, population, region), and diagnosis of brucellosis.Results:A total of 1 417 brucellosis cases were reported in Qujing City from 2008 to 2023, with no death. The annual average incidence of brucellosis was 1.49/100 000, with no cases reported in 2009 and 2010, and the highest incidence in 2023 (7.82/100 000). The incidence of brucellosis showed an increasing trend year by year (χ 2trend = 1 874.58, P < 0.001). The number of cases from June to November accounted for 61.54% (872/1 417). The majority of brucellosis cases were in the age group of 36 - 65 years old, accounting for 67.82% (961/1 417). Among them, there were 954 males and 463 females, with a gender ratio of 2.06 ∶ 1.00. Farmers were the main occupation, accounting for 84.33% (1 195/1 417). The cases were mainly distributed in Luliang County (621 cases), Xuanwei City (282 cases) and Shizong County (137 cases), accounting for 73.39% (1 040/1 417). The median interval between onset and diagnosis was 13 days, and the cases with intervals ≤7 d, 8 - 30 d, and ≥31 d accounted for 32.11% (455/1 417), 40.16% (569/1 417), and 27.73% (393/1 417), respectively. Totally 63.94% (906/1 417) of the cases were confirmed in medical institutions in Qujing City. Conclusions:The incidence of brucellosis in Qujing City is increasing year by year, with men, middle-aged and elderly people and farmers as the main population, summer and autumn as the peak period, and Luliang County, Xuanwei City and Shizong County as the high incidence areas. Most cases have an interval of less than 30 days between onset and diagnosis, and can be diagnosed within the jurisdiction.