1.Engineered Bacteriophages for The Treatment of Multidrug-resistant Bacterial Infections
Yu-Ying CHEN ; Chun-Mei HUANG ; Jin-Zhi PAN ; De-Liang LIU ; Yang ZHOU ; Gui-Qin DAI ; Peng-Fei ZHAO ; Hong-Zhou LU ; Ming-Bin ZHENG
Progress in Biochemistry and Biophysics 2026;53(6):1581-1596
Multidrug-resistant (MDR) bacterial infections have emerged as a serious challenge of global public health crisis. The overuse and misuse of conventional antibiotics have dramatically accelerated the emergence, evolution and worldwide spread of drug-resistant bacterial strains, necessitating urgent exploration of novel antibacterial strategies. Bacteriophages serve as natural bacterial predators offering distinct advantages including high host specificity, autonomous self-replication capabilities and cost-effective large-scale production. However, wild-type phages present significant clinical limitations due to their narrow host ranges, susceptibility to rapid immune clearance and poor penetration of bacterial biofilms, which severely restrict their therapeutic applications. The convergence of synthetic biology, nanotechnology and advanced gene editing technologies has accelerated the development of engineered bacteriophage platforms, providing programmable, scalable and clinically translatable pathways to overcome these inherent biological constraints. Here, we systematically delineate four fundamental strategies for engineered bacteriophage development. Chemical modification utilizes reactive functional groups such as amino, carboxyl and thiol moieties on capsid proteins through esterification, amidation or click chemistry reactions to achieve precise drug conjugation and surface functionalization. In vivo editing encompasses ultraviolet or chemical mutagenesis for random mutation induction, homologous recombination for targeted genetic alterations, recombineering methodologies including electroporation-mediated bacteriophage recombination engineering, and CRISPR-Cas systems for precise genome editing to enable exact genetic reconstruction and host range reprogramming. In vitro synthesis leverages genome engineering platforms where intact phage genomes are transferred into yeast or host bacteria to facilitate highly efficient homologous recombination, enabling large DNA fragment assembly and cross-gene host range expansion without bacterial toxicity constraints. Directed evolution combines artificial selection through mutation library screening with rational design approaches involving chimeric receptor binding protein construction or site-specific mutagenesis, effectively balancing the discovery of unknown adaptive pathways with targeted host specificity modification. Moreover, we comprehensively discuss therapeutic applications across diverse clinical scenarios. Engineered bacteriophage effectively disrupt bacterial biofilms through sophisticated functionalized delivery platforms including nanozyme-conjugated phages, phage-liposome nanoconjugates and bio-responsive hydrogels, demonstrating significantly enhanced bactericidal efficiency compared to unmodified free phages. These bioengineered vectors attenuate bacterial virulence and resensitize pathogens to antibiotics by delivering CRISPR-Cas systems or base editors to disrupt critical virulence factors such as pili, capsule synthesis machineries and quorum sensing systems, or by inactivating antibiotic resistance determinants including beta-lactamase genes. As an intelligent nanomedicine delivery platform, engineered bacteriophage enable precise pathogen elimination an through photocatalytic reactive oxygen species generation, immunomodulatory interventions, or controlled release of antibacterial drugs. Furthermore, oral administration of engineered bacteriophage facilitates microbiota modulation, which selectively eliminate intestinal pathogens while preserve beneficial commensal microbiota, thereby restoring microbial community balance and preventing complications associated with dysbiosis. Finally, we critically analyze persistent challenges including host strain matching complexity, evolution of bacterial resistance mechanisms, pharmacokinetic optimization requirements, optimal administration route selection, large-scale production quality control standards and clinical dosing determination protocols. Through multidisciplinary integration of synthetic biology, infectious disease medicine and immunology, future translational medicine studies of bacteriophage should establish comprehensive technical platforms encompassing rapid phage screening, intelligent rational design, rigorous in vivo evaluation and standardized clinical validation processes, ultimately advancing engineered bacteriophage from laboratory innovations to clinically approved therapeutics for effectively combating MDR bacterial infections.
2.Identification and infection rate of densovirus in Culex pipiens pallens in Beijing in 2023
Xiu-yan XU ; Ting YAN ; Si-jie ZHU ; Jing LI ; Mei-de LIU ; Hong-jiang ZHANG ; Ting LIU ; Qiu-hong LI ; Xiao-jie ZHOU ; Ying TONG ; Yong ZHANG
Acta Parasitologica et Medica Entomologica Sinica 2026;33(1):25-30
Objective This study conducted molecular biological identification of the viruses carried by Culex pipiens pallens specimens collected in Shunyi District, Beijing in 2023, and observed the changes in the infection rate of the viruses carried by Cx. pipiens pallens at different collection times. Methods Cx. pipiens pallens were collected using carbon dioxide mosquito traps. The mosquito samples were ground in batches and analyzed by molecular biology technologies. The virus infection rate at different collection times was analyzed statistically. Results 17 strains of Culex pipiens pallens densovirus(CppDNV)were identified from Cx. pipiens pallens samples collected in Shunyi District, Beijing, in 2023. The nucleotide sequence analysis of the virus genome coding region showed that CppDNV was a single-stranded DNA virus with a total length of 3 335 nt, encoding 2 non-structural proteins(NS1, NS2)and 1 capsid protein(VP). The nucleotide(amino acid)sequence lengths of the three proteins were 2 376 nt(791 aa),1 092 nt(363 aa)and 1 071 nt(356 aa), respectively. Phylogenetic analysis showed that CppDNV was located in genus Brevihamaparvovirus. Statistical analysis showed no significant difference in infection rates across collection times(χ2=4.429, P=0.194). Conclusions CppDNV was identified in Cx. pipiens pallens in Beijing, and it was stably maintained in this natural population.
3.Analysis of Risk Factors for Early Relapse/Progression in Patients with Multiple Myeloma and Development of a Nomogram Predic-tion Model
Mei-Jiao HUANG ; Yu LIU ; Hong-Yan WANG ; Tai-Ran CHEN ; Xing-Li ZOU
Journal of Experimental Hematology 2025;33(6):1655-1661
Objective:To analyze the potential risk factors for early relapse/progression in patients with multiple myeloma(MM)and develop a risk prediction model based on these factors.Methods:A retrospective analysis was conducted on 187 newly diagnosed multiple myeloma(NDMM)patients who treated at the Affiliated Hospital of North Sichuan Medical College from February 2014 to December 2020.The clinical,laboratory examination,and follow-up data of patients experiencing relapse/progression within 24 months after treatment(ER/EP24)were analyzed using univariate and multivariate analyses,and a nomogram prediction model was established.Results:Among the 187 patients,58(31.0%)experienced ER/EP24,with a median survival time of only 24 months.The results of multivariate logistic regression analysis showed that failure to achieve partial response(PR)or better after 3-4 cycles of chemotherapy and albumin(ALB)levels<35 g/L were independent risk factors for ER/EP24(P<0.05).These factors,along with other clinically relevant variables,were further incorporated into the nomogram prediction model.The model demonstrated a concordance index(C-index)of 0.784,indicating strong predictive accuracy.Conclusion:MM patients experiencing ER/EP24 exhibit poor outcome,and the nomogram model developed in this study effectively predicts the risk of ER/EP24 in NDMM patients,providing a valuable tool for clinical risk assessment.
4.Investigation of plague sources in the border port areas of Longchuan County, Yunnan Province in 2022
Zhengxiang LIU ; Yuqiong LI ; Mei HONG ; Wei LIANG ; Qiuxiang YANG ; Shilong YANG ; Cuicui ZHAO ; Zihou GAO ; Zongti SHAO
Chinese Journal of Endemiology 2025;44(6):467-471
Objective:To investigate the host and vector composition of pestis and the epidemic situation of pestis among animals in the border port areas of Longchuan County, Yunnan Province.Methods:In September 2022, a survey was conducted on rodents and their surface parasitic fleas in the border port areas of Longchuan County, according to three habitat types: residential areas, agricultural areas, and forest-shrubbery areas. Samples of murine animals organs and their surface parasitic fleas were collected for isolation and identification of Yersinia pestis. Blood samples of plague indicating animals, such as murine animals, dogs and cats were collected, and serum plague F1 antibody was detected by indirect hemagglutination assay. Meanwhile, a retrospective investigation was conducted on the occurrence of self dead rats, sick rats, and suspected cases in the local area from 2018 to 2022 through interviews with farmers. Results:A total of 168 murine animals belonging to 3 orders, 5 families, 10 genera, and 11 species were captured in three habitats in Longchuan County. Among them, the capture rate in residential areas was 5.00% (30/600), with Rattus tanezumi and Suncus murinus as dominant species, with a composition ratio of 50.00% (15/30). The capture rate in agricultural areas was 9.67% (122/1 262), with Rattus tanezumi and Suncus murinus as dominant species, with a composition ratio of 50.82% (62/122) and 44.26% (54/122), respectively. The capture rate in the forest-shrubbery areas was 6.25% (16/256), with Hylomys suillus and Eothenomys eleusis as dominant species, with a composition ratio of 37.50% (6/16) and 31.25% (5/16), respectively. Among the captured murine animals, 20 individuals carried 52 parasitic fleas, belonging to 2 species of 2 genera and 2 families. The total flea infection rate was 11.90% (20/168), and the total flea index was 0.31 (52/168). The dominant specie was Xenopsylla cheopis (90.38%, 47/52). The flea infection rate in residential areas was 33.33% (10/30), and the flea index was 1.23 (37/30). The flea infection rate in agricultural areas was 7.38% (9/122), and the flea index was 0.11 (14/122). The flea infection rate in the forest-shrubbery areas was 6.25% (1/16), and the flea index was 0.06 (1/16). The samples of murine animals and their parasitic fleas obtained were isolated and cultured by Yersinia pestis, and the results were negative. A total of 144 serum samples from murine animals, dogs and cats were separated, and no F1 antibody against pestis was detected. According to interviews and investigations, no abnormal situations such as a large number of self dead rats, sick rats, and suspected cases were found from 2018 to 2022. Conclusions:No plague epidemic has been found in the border port areas of Longchuan County recently. The main host of plague, Rattus tanezumi, and the main vector, Xenopsylla cheopis, remain the dominant species in this area.
5.Newly formulated Tadalafil tablets alleviates liver fibrosis in mice by inhibiting activation of hepatic stellate cells
Wen-bin FENG ; Jian-qin YANG ; Li-mei LI ; Jia-xiu LEI ; Fan LIU ; Zi-jian ZHAO ; Yun-ping MU ; Fang-hong LI
Chinese Pharmacological Bulletin 2025;41(2):290-297
Aim To investigate the therapeutic effect of newly formulated Tadalafil tablets on liver fibrosis in mice induced by carbon tetrachloride(CCl4)and its impact on the activation of hepatic stellate cells(HSCs).Methods Liver fibrosis model was estab-lished by intraperitoneally injecting 20%CCl4 corn oil solution twice a week for eight weeks.After four weeks of modeling,the treatment group was administered ei-ther the newly formulated Tadalafil tablets(1.0 mg·kg-1)or the Cialis(2.5 mg·kg-1)via gavage for the remaining four weeks.We assessed the effects of Tadalafil on collagen deposition,tissue structural dam-age,and HSCs activation markers in the fibrotic liver of mice using serum biochemical analysis,histopathologi-cal staining,and Western blotting following the treat-ment period.LX-2 cells were cultured and treated with tadalafil after TGF β1 stimulation,and the effects of tadalafil on LX-2 cell activation were assessed via Western blot.Results Compared to the normal mice,the model group mice exhibited a significantly higher liver-specific index,increased liver function indicators,and notable hepatocyte necrosis.Additionally,liver lobules were damaged,accompanied by severe infiltra-tion of inflammatory cells.Both smooth muscle actin(α-SMA)and fibronectin(Fn)were elevated,serving as markers of HSCs activation.As a result of treatment with the newly formulated Tadalafil tablets,liver tissue damage was significantly reduced,transaminase levels decreased,necrosis and inflammatory cell infiltration were reduced,and collagen fiber deposition was allevia-ted,and α-SMA and Fn expression was reduced.It was worth noting that low-dose newly formulated Tadalafil tablets were found to be as effective as high-dose Cia-lis.In a cellular model,Tadalafil significantly inhibited the activation of LX-2 cells and reduced the expression of proteins related to cell activation.Conclusions The newly formulated Tadalafil tablets can significantly inhibit HSCs activation,reduce extracellular matrix(ECM)deposition,improve liver fibrosis and liver function damage caused by CCl4.This new formulation offers a significant advantage over Cialis in terms of ef-fectiveness,with a lower effective dose.
6.Analysis of Lung Cancer Screening Compliance Among High-Risk Population in Chongqing from 2013 to 2021
Lu XIAO ; Shenglin ZHAO ; Zhikai YU ; Jia DU ; Yan ZHANG ; Xiu LIU ; Qing GUO ; Hong ZHOU ; Mei HE
China Cancer 2025;34(3):203-208
[Purpose]To analyze the compliance and its influencing factors of lung cancer screening using low-dose computed tomography(LDCT)among high-risk population in urban districts of Chongqing from 2013 to 2021.[Methods]The lung cancer screeing of Cancer Early Diagnosis and Treatment Project was conducted among permanent residents aged 40~69 years old from 14 urban districts of Chongqing selected by cluster sampling method from 2013 to 2021.The questionnaire survey was performed to assess the risk level of lung cancer,and individuals with high risk were advised to have LDCT examination.The compliance rate of LDCT examination among high-risk populations was calculated and compared using Chi-square test among residents with different de-mographic features;the influencing factors of compliance was analyzed with generalized linear mixed models.[Results]A total of 316 066 residents completed the risk assessment questionnaire survey,52 858 people were assessed as high-risk(17.17%).Among the high-risk population,20 398 completed LDCT screening,with an overall compliance rate of 38.59%.The generalized linear mixed model showed that male participants(OR=0.871,95%CI:0.823~0.922)and smokers(light smokers:OR=0.829,95%CI:0.775~0.886;heavy smokers:OR=0.842,95%CI:0.792~0.896)had lower compliance rates;while people with higher education level(OR=1.347,95%CI:1.265~1.435),occupational exposure to harmful substances(OR=1.400,95%CI:1.340~1.463),passive smoking for 20 years or more(OR=1.472,95%CI:1.376~1.576),infrequent physical exercise(OR=1.203,95%CI:1.152~1.256),family history of lung cancer(OR=2.312,95%CI:2.201~2.429),and those having media promotion by community staff(OR=1.365,95%CI:1.223~1.524),and trained community staff(OR=1.343,95%CI:1.227~1.470)had higher compliance rates.Comorbidities were also factors influencing compliance,and there was an increasing trend of compliance rate with the increase of comorbidity numbers(P<0.001).[Conclusion]The compli-ance rate of LDCT examination for lung cancer screening in Chongqing needs to be improved,and more precise health education should be implemented for groups with different characteristics to improve the compliance among high-risk population.
7.Chemical constituents from Commelina communis
Hong-ting YI ; Ding-mei LIANG ; Bin LEI ; Hong-ling ZENG ; Zhong-wen CHEN ; Hua LIU ; Feng LIU
Chinese Traditional Patent Medicine 2025;47(3):827-833
AIM To study the chemical constituents from Commelina communis L.METHODS The 95%ethanol extract from C.Communis was isolated and purified by activated charcoal,silica gel,Sephadex LH-20,and HPLC,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Seventeen compounds were isolated and identified as p-hydroxyl ethyl cinnamate(1),p-hydroxybenzaldehyde(2),vanillin(3),4-hydroxy-2,3-dimethyl-2-nonen-4-olide(4),hemeratrol A(5),chakyunglupulin B(6),chakyunglupulin A(7),2-(2-hydroxyethyl)-3-methylfumaric acid(8),N-cis-feruloyl tyramine(9),N-trans-coumaroyltyramine(10),5,6,7,3',4',5'-hexamethoxyflavone(11),N-trans-sinapoyltyramine(12),dihydro-feruloyltyramine(13),N-trans-feruloyltyramine(14),2-phenylethanol-β-D-glucoside(15),quercetin-3-O-β-D-glucoside(16),and isorhamnetin-3-O-β-D-glucopyranoside(17).CONCLUSION Compounds 4-8,10 and 11 are isolated from Commelina genus for the first time,and 1,9,12-15 are first isolated from this plant.
8.Stability of salvianolic acid B based on degradation kinetic models
Wen-kang LIU ; Xian-run HU ; Xue-mei CHENG ; Wei LIU ; Hai WEI ; Chang-hong WANG
Chinese Traditional Patent Medicine 2025;47(3):733-739
AIM To investigate the stability of salvianolic acid B.METHODS HPLC was adopted in the content determination of salvianolic acid B,after which the chemical stability in different pH of buffer solutions,oxidation stability in different concentrations of H2O2,and biological stability in artificial gastric fluid,artificial intestinal fluid and biological matrices were analyzed,and its degradation kinetics was fitted.RESULTS Salvianolic acid B was stable in acidic and weakly acidic buffer solutions and artificial gastric fluid,which demonstrated poor stability in neutral and alkaline buffer solutions,artificial intestinal fluid,H2O2 and biological matrices.The degradation process of this constituent accorded with the first-order kinetic model in ileum homogenate,and the second-order kinetic model in pH 7.4 buffer solution,artificial intestinal fluid,H2O2 and stomach,duodenum,jejunum,colon homogenates.CONCLUSION Biological matrices,oxidants and alkaline environment can affect the stability of salvianolic acid B.This experimental exhibits important significance for the development and application of salvianolic acid B-related products.
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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