1.Differences in deltamethrin resistance and kdr gene mutation in Culex tritaeniorhynchus population in and outside the Yellow Sea wetland
Xiao-er ZHANG ; Zhi-ming WU ; Ye TIAN ; Qian CUI ; Yu-qian JI ; Huan WANG ; Shu-juan YANG ; Yi-chao ZHAO ; Yu WANG ; Hua-yu YIN ; Yu DING ; Guo-jin YAN ; Min-sen ZHAO ; Shou-gang ZHANG ; Bing-dong SONG ; Hong-na CHEN ; Jian GAO ; Wei-fang YANG ; Yu-fu ZHANG ; Hui LIU ; Hong-liang CHU
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):101-107
Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.
2.Comparison of Logistic Regression and Machine Learning Approaches in Predicting Depressive Symptoms: A National-Based Study
Xing-Xuan DONG ; Jian-Hua LIU ; Tian-Yang ZHANG ; Chen-Wei PAN ; Chun-Hua ZHAO ; Yi-Bo WU ; Dan-Dan CHEN
Psychiatry Investigation 2025;22(3):267-278
Objective:
Machine learning (ML) has been reported to have better predictive capability than traditional statistical techniques. The aim of this study was to assess the efficacy of ML algorithms and logistic regression (LR) for predicting depressive symptoms during the COVID-19 pandemic.
Methods:
Analyses were carried out in a national cross-sectional study involving 21,916 participants. The ML algorithms in this study included random forest (RF), support vector machine (SVM), neural network (NN), and gradient boosting machine (GBM) methods. The performance indices were sensitivity, specificity, accuracy, precision, F1-score, and area under the receiver operating characteristic curve (AUC).
Results:
LR and NN had the best performance in terms of AUCs. The risk of overfitting was found to be negligible for most ML models except for RF, and GBM obtained the highest sensitivity, specificity, accuracy, precision, and F1-score. Therefore, LR, NN, and GBM models ranked among the best models.
Conclusion
Compared with ML models, LR model performed comparably to ML models in predicting depressive symptoms and identifying potential risk factors while also exhibiting a lower risk of overfitting.
3.Comparison of Logistic Regression and Machine Learning Approaches in Predicting Depressive Symptoms: A National-Based Study
Xing-Xuan DONG ; Jian-Hua LIU ; Tian-Yang ZHANG ; Chen-Wei PAN ; Chun-Hua ZHAO ; Yi-Bo WU ; Dan-Dan CHEN
Psychiatry Investigation 2025;22(3):267-278
Objective:
Machine learning (ML) has been reported to have better predictive capability than traditional statistical techniques. The aim of this study was to assess the efficacy of ML algorithms and logistic regression (LR) for predicting depressive symptoms during the COVID-19 pandemic.
Methods:
Analyses were carried out in a national cross-sectional study involving 21,916 participants. The ML algorithms in this study included random forest (RF), support vector machine (SVM), neural network (NN), and gradient boosting machine (GBM) methods. The performance indices were sensitivity, specificity, accuracy, precision, F1-score, and area under the receiver operating characteristic curve (AUC).
Results:
LR and NN had the best performance in terms of AUCs. The risk of overfitting was found to be negligible for most ML models except for RF, and GBM obtained the highest sensitivity, specificity, accuracy, precision, and F1-score. Therefore, LR, NN, and GBM models ranked among the best models.
Conclusion
Compared with ML models, LR model performed comparably to ML models in predicting depressive symptoms and identifying potential risk factors while also exhibiting a lower risk of overfitting.
4.Construction and biological characterization of a dual sagA/aroA gene deletion mutant strain of donkey-derived Streptococcus equi subsp. equi
Bing LIU ; Guangyuan LIU ; Nannan GAO ; Zhaoliang DING ; Jie YU ; Chuanlu WEI ; Haijing LI ; Hua WANG ; Shishan DONG ; Jianbao DONG
Chinese Journal of Veterinary Science 2025;45(11):2365-2371
Strangles,caused by Streptococcus equi subsp.equi,remains one of the most prevalent and high-incidence infectious diseases in intensive donkey farms,posing a significant threat to the healthy development of the donkey industry.Vaccination serves as an effective measure for the pre-vention and control of the disease,however,there is currently no attenuated vaccine against this disease in China.To provide a candidate strain for the development of a live attenuated strangles vaccine,this study focused on a wild-type S.equi subsp.equi strain isolated from donkeys.Using homologous recombination gene knockout technology,the aroA gene(encoding 5-enolpyru-vylshikimate-3-phosphate synthase)and the sag A gene(encoding the precursor of streptolysin S toxin)were sequentially deleted to construct a double-gene-deletion strain(ΔsagA/aroA).The virulence and key biological characteristics of the mutant strain were systematically evaluated.TheΔsagA/aroA strain was successfully generated,exhibiting complete loss of hemolytic activity and maintaining stable genetic inheritance over 60 consecutive passages.Electron microscopy revealed that the mutant retained morphological characteristics compared to the wild-type strain,and its growth rate was significantly slower(P<0.000 1).Virulence assessment using a challenge dose of 1× 105 CFU/0.2 mL(the minimum fully lethal dose of the wild-type strain)demonstrated markedly attenuated virulence in the mutant.Immunization trials with 1 ×104 CFU/0.2 mL of theΔsagA/aroA strain revealed a increase in ELISA antibody titers by day 7 post-vaccination,and higher levels at days 14 and 21.Notably,antibody levels in the experimental group were significant-ly higher than those in the control group(P<0.000 1).These findings confirm that the double-gene-deletion strain S.equi subsp.equi ΔsagA/aroA exhibits reduced virulence while retaining im-munogenicity,which suggested it can be used as a promising candidate strain for further develop-ment of a live attenuated strangles vaccine.
5.Differential expression of retinal mRNA in experimental autoimmune uveitis mice based on transcriptome sequencing
Qiang LIU ; Rongfeng LIAO ; Hua YU ; Lihong DONG
Chinese Journal of Experimental Ophthalmology 2025;43(9):786-792
Objective:To screen differentially expressed genes in the retinas of mice with experimental autoimmune uveitis (EAU) through transcriptome sequencing.Methods:Twenty 8-week-old SPF grade male C57BL/6J mice were randomly divided into EAU group and control group by random number table method, with 10 mice in each group.In the EAU group, an emulsion of interphotoreceptor retinoid-binding protein 1-20 and complete Freund adjuvant was injected subcutaneously into the inner side of the hind limbs and intravenously into the tail vein of the mice, and pertussis toxin was injected intraperitoneally to establish the EAU model.In the control group, mice were subcutaneously injected with the corresponding volume of phosphate buffer solution.On the 21st day after model establishment, the anterior segment inflammation of the mouse eyes was examined using a slit-lamp microscope.Retinal blood vessels were observed by fundus photography and clinical inflammation was scored.Hematoxylin-eosin staining was used to observe the morphological changes in the retinal tissues of the two groups.Retinal tissues were collected from two groups of mice.RNA was extracted and cDNA libraries were constructed for transcriptome sequencing.The clusterProfiler package in R programming language was used to screen for differentially expressed genes in EAU, and to conduct GO and KEGG enrichment analyses.The expression of core differentially expressed genes in the retinal tissues was then verified using real-time fluorescent quantitative PCR.The breeding and use of experimental animals were in compliance with the relevant regulations of the Animal Ethics Committee of Anhui Medical University.The study protocol was approved by the Ethics Committee of Anhui Medical University (No.LLSC20221208).Results:On the 21st day after model establishment, the clinical score of the EAU group was 2.83±0.94, significantly higher than 1.89±0.93 of the control group, and the difference was statistically significant ( t=2.290, P<0.05). The retinal blood vessels of mice in the EAU group showed tortuosity and dilation.Histopathological examination revealed a large number of inflammatory cell infiltrations in the retina, indicating successful establishment of the EAU mouse model.Transcriptome sequencing of the mouse retinal tissues identified a total of 32 473 genes, and 154 differentially expressed genes were screened out.Among them, 79 genes were up-regulated with Gm38574, Tmem81, Ptpn7 being top three and 75 genes were down-regulated with Gm19802, Fga, Cyp3a11 being top three.GO enrichment analysis showed that the differentially expressed genes were mostly related to immune response and cytokine action.KEGG pathway enrichment analysis showed that the differentially expressed genes were mainly enriched in the Toll-like pathway and cytokine signaling pathway.Compared with the control group, the relative expression levels of Gm38574, Tmem81, and Ptpn7 in the retinal tissues of the EAU group were up-regulated, while the expression levels of Gm19802, Fga, and Cyp3a11 were down-regulated, and the differences were statistically significant ( t=9.755, 5.358, 6.289, 4.312, 6.577, 6.118; all P<0.05). Conclusions:There are significant differences in the key genes Gm38574, Tmem81, Ptpn7, Gm19802, Fga, and Cyp3a11 in the retinal tissues of EAU mice, mainly corelated with the cytokine interaction pathway, Toll-like receptor signaling pathway.
6.Evaluation of assistive device adaptation and analysis of influencing factors among people with dysfunction
Chen LIU ; Liquan DONG ; Mei YAN ; Hua JIANG
Chinese Journal of Rehabilitation Theory and Practice 2025;31(11):1354-1364
Objective To investigate the current status of assistive device adaptation among people with dysfunction in China,identi-fy unmet assistive needs for assistive products,and determine key factors influencing attitudes toward assistive device use.Methods Based on data from the Chinese segment of the Global Rapid Assistive Technology Assessment(rATA)survey,5 935 individuals with dysfunction from Beijing,Anhui,Fujian,Hubei,Sichuan and Shaanxi were included.The adaptation status of assistive devices was analyzed,and a theoretical framework was constructed using the tech-nology acceptance model.Multiple linear regression analysis was applied to identify factors influencing attitudes toward assistive device use.Results The utilization rate of rehabilitation assistive devices among people with dysfunction was 65.9%,with a notable prevalence of multiple functional impairments.Fit rate was the highest(68.44%)in individuals with visual im-pairments,while those with communication impairments had the lowest(1.52%).Fit rates were significantly low-er among rural residents and older adults.Overall satisfaction with assistive devices was relatively high(4.11±0.71).Accessibility of the home environment(B=0.396,P<0.001),accessibility of the public environment(B=0.204,P<0.001),functional utility of assistive devices(B=0.204,P<0.001),and distance to obtain the devices(B<-0.112,P<0.01)were key factors affecting satisfication toward assistive device use,while the source of payment showed no significant impact(P>0.05).Conclusion Significant structural imbalances and group disparities exist in the adaptation of assistive devices among people with dysfunction in China.The phenomenon of multiple functional impairments has not received suffi-cient attention,and there remains a substantial unmet need for assistive products among non-fitted groups.Al-though overall satisfaction with assistive devices is high,influencing factors are complex.Continuous improve-ment of accessibility in both private and public environments,promotion of personalized adaptation services,and optimization of assistive device service networks are essential to enhance adaptation accuracy,sustained use,and subjective well-being among people with dysfunction.
7.The longitudinal effect of learning stress on learning burnout in vocational college students: mediating effect of academic procrastination
Hua WEI ; Yuejuan DONG ; Yanlei LIU ; Xinli CHEN ; Zi ZENG ; Shan YUE ; Wei WU ; Hui LIU
Chinese Journal of Behavioral Medicine and Brain Science 2025;34(9):840-845
Objective:To explore the longitudinal effect of learning stress on learning burnout in vocational college students, and the mediating role of academic procrastination.Methods:A total of 1 212 vocational college students were selected, and two follow-up surveys were conducted at 12-week intervals in September (T1) and November (T2) of 2024 using the basic situation questionnaire, the burnout inventory-student survey, the learning pressure questionnaire and the brief academic procrastination scale. SPSS 26.0 software was used to compare the demographic characteristics of students' depersonalization using t test and single factor analysis of variance. Bootstrap was used to analyze the relationship among learning stress, academic procrastination and learning burnout. Results:The scores of learning stress at T1 and T2 for vocational college students were 14.47±3.52 and 14.52 ±3.50, the scores of academic procrastination at T1 and T2 were 27.14±9.07 and 27.21±9.04, and the scores of learning burnout T1 and T2 were 39.38±8.76 and 39.69±8.79.The t-test showed that the score of learning burnout at T1 of students aged 18 and below (36.70±8.72) was lower than students aged 18 above (40.15±8.63, t=-5.81, P<0.01). The score of learning burnout for liberal arts students at T1(40.82±8.54) was higher than that of science students (37.68±8.72, t=6.31, P<0.01). Single factor analysis of variance showed that the score of learning burnout for grade 1 students at T1(35.19±8.45) was lower than that of grade 2 students (41.33±7.98) and grade 3 students (38.92±9.88), and learning burnout score of grade 2 students at T1 was higher than that of grades 3 students ( F=61.59, P<0.01). The score of learning burnout for high-achieving students at T1(36.23±8.34) was lower than that of middle-achieving students (39.82±8.52) and low-achieving students (45.42±9.14), and the score of learning burnout for middle-achieving students at T1 were lower than that of low-achieving students ( F=36.53, P<0.01). Bootstrap test showed that academic procrastination T2 played a partial mediating role in the relationship between learning stress T1 and learning burnout T2 (effect size=0.04, 95% CI=0.03-0.07). Academic procrastination T1 played a partial mediating role in the relationship between learning stress T1 and learning burnout T2 (effect size=0.05, 95% CI=0.04-0.07). Conclusion:Learning stress can directly affect learning burnout in vocational college students, and also can indirectly affect learning burnout through the mediating effect of academic procrastination.
8.Prognostic analysis of patients with left main coronary artery disease complicated by chronic kidney disease undergoing intravascular ultrasound-guided coronary intervention therapy
Dong YI ; Chen-wei MENG ; Xun JIAN ; Dao-quan LIU ; Lin XU ; Ting LUO ; Hua YAN
Chinese Journal of Interventional Cardiology 2025;33(9):500-508
Objective To elucidate the impact of chronic kidney disease(CKD)on the clinical outcomes of patients with left main coronary artery disease(LMCAD)undergoing intravascular ultrasound(IVUS)-guided percutaneous coronary intervention(PCI).Methods This retrospective study enrolled consecutive patients with LMCAD who underwent IVUS-guided PCI at Wuhan Asia Heart Hospital between January 2017 and December 2020.Patients were stratified into CKD and non-CKD groups according to the presence of CKD.Clinical data were systematically retrieved from the electronic health record system.Demographic,clinical,and angiographic characteristics were compared between groups.The primary endpoint was major adverse cardiovascular events(MACE),defined as a composite of all-cause mortality,myocardial infarction,and ischemic stroke.Results A total of 325 LMCAD patients[mean age(62.56±9.86)years;73.54%male]were included,with 31 patients(9.54%)in the CKD group.During a median follow-up of 5 years,CKD patients exhibited significantly older age[(70.13±9.77)years vs.(61.77±9.54)years,P<0.001],higher prevalence of three-vessel disease(64.52%vs.38.10%;P=0.040)and left main bifurcation lesion(45.16%vs.37.76%,P=0.011),greater IVUS-detected calcification burden(P=0.029),and higher median SYNTAXⅡ scores[(34.10(30.30,39.25)vs.26.75(22.42,31.58),P<0.001)].The cumulative incidence of MACE was significantly higher in the CKD group compared to the non-CKD group(32.26%vs.9.18%,P<0.001).Univariate Cox regression analysis and Kaplan-Meier survival curves confirmed a 5.877-fold increased risk of MACE in CKD patients(95%CI 2.765-12.494).After adjusting for age and cardiac function,CKD remained an independent predictor of MACE(HR 3.611,95%CI 1.634-7.978).Conclusions LMCAD patients with concomitant CKD present with advanced age,impaired cardiac function,more extensive coronary disease,and severe calcification.The presence of CKD is associated with a significantly worse long-term prognosis.
9.Distribution and resistance profiles of bacterial strains isolated from cerebrospinal fluid in hospitals across China:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Juan MA ; Lixia ZHANG ; Yang YANG ; Fupin HU ; Demei ZHU ; Han SHEN ; Wanqing ZHOU ; Wenen LIU ; Yanming LI ; Yi XIE ; Mei KANG ; Dawen GUO ; Jinying ZHAO ; Zhidong HU ; Jin LI ; Shanmei WANG ; Yafei CHU ; Yunsong YU ; Jie LIN ; Yingchun XU ; Xiaojiang ZHANG ; Jihong LI ; Bin SHAN ; Yan DU ; Ping JI ; Fengbo ZHANG ; Chao ZHUO ; Danhong SU ; Lianhua WEI ; Fengmei ZOU ; Xiaobo MA ; Yanping ZHENG ; Yuanhong XU ; Ying HUANG ; Yunzhuo CHU ; Sufei TIAN ; Hua YU ; Xiangning HUANG ; Sufang GUO ; Xuesong XU ; Chao YAN ; Fangfang HU ; Yan JIN ; Chunhong SHAO ; Wei JIA ; Gang LI ; Jinsong WU ; Yuemei LU ; Fang DONG ; Zhiyong LÜ ; Lei ZHU ; Jinhua MENG ; Shuping ZHOU ; Yan ZHOU ; Chuanqing WANG ; Pan FU ; Yunjian HU ; Xiaoman AI ; Ziyong SUN ; Zhongju CHEN ; Hong ZHANG ; Chun WANG ; Yuxing NI ; Jingyong SUN ; Kaizhen WEN ; Yirong ZHANG ; Ruyi GUO ; Yan ZHU ; Jinju DUAN ; Jianbang KANG ; Xuefei HU ; Shifu WANG ; Yunsheng CHEN ; Qing MENG ; Yong ZHAO ; Ping GONG ; Ruizhong WANG ; Hua FANG ; Jilu SHEN ; Jiangshan LIU ; Hongqin GU ; Jiao FENG ; Shunhong XUE ; Bixia YU ; Wen HE ; Lin JIANG ; Longfeng LIAO ; Chunlei YUE ; Wenhui HUANG
Chinese Journal of Infection and Chemotherapy 2025;25(3):279-289
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.
10.Changing antibiotic resistance profiles of the bacterial strains isolated from geriatric patients in hospitals across China:data from CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Xiaoman AI ; Yunjian HU ; Chunyue GE ; Yang YANG ; Fupin HU ; Demei ZHU ; Yingchun XU ; Xiaojiang ZHANG ; Hui LI ; Ping JI ; Yi XIE ; Mei KANG ; Chuanqing WANG ; Pan FU ; Yuanhong XU ; Ying HUANG ; Ziyong SUN ; Zhongju CHEN ; Yuxing NI ; Jingyong SUN ; Yunzhuo CHU ; Sufei TIAN ; Zhidong HU ; Jin LI ; Yunsong YU ; Jie LIN ; Bin SHAN ; Yan DU ; Sufang GUO ; Lianhua WEI ; Fengmei ZOU ; Hong ZHANG ; Chun WANG ; Chao ZHUO ; Danhong SU ; Dawen GUO ; Jinying ZHAO ; Hua YU ; Xiangning HUANG ; Wen'en LIU ; Yanming LI ; Yan JIN ; Chunhong SHAO ; Xuesong XU ; Chao YAN ; Shanmei WANG ; Yafei CHU ; Lixia ZHANG ; Juan MA ; Shuping ZHOU ; Yan ZHOU ; Lei ZHU ; Jinhua MENG ; Fang DONG ; Zhiyong LÜ ; Fangfang HU ; Han SHEN ; Wanqing ZHOU ; Wei JIA ; Gang LI ; Jinsong WU ; Yuemei LU ; Jihong LI ; Jinju DUAN ; Jianbang KANG ; Xiaobo MA ; Yanping ZHENG ; Ruyi GUO ; Yan ZHU ; Yunsheng CHEN ; Qing MENG ; Shifu WANG ; Xuefei HU ; Jilu SHEN ; Wenhui HUANG ; Ruizhong WANG ; Hua FANG ; Bixia YU ; Yong ZHAO ; Ping GONG ; Kaizhen WENG ; Yirong ZHANG ; Jiangshan LIU ; Longfeng LIAO ; Hongqin GU ; Lin JIANG ; Wen HE ; Shunhong XUE ; Jiao FENG ; Chunlei YUE
Chinese Journal of Infection and Chemotherapy 2025;25(3):290-302
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.


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