1.The mechanism of Laggerae Herba in improving chronic heart failure by inhibiting ferroptosis through the Nrf2/SLC7A11/GPX4 signaling pathway
Jinling XIAO ; Kai HUANG ; Xiaoqi WEI ; Xinyi FAN ; Wangjing CHAI ; Jing HAN ; Kuo GAO ; Xue YU ; Fanghe LI ; Shuzhen GUO
Journal of Beijing University of Traditional Chinese Medicine 2025;48(3):343-353
Objective:
To investigate the role and mechanism of the heat-clearing and detoxifying drug Laggerae Herba in regulating the nuclear factor-erythroid 2-related factor-2(Nrf2)/solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) signaling pathway to inhibit ferroptosis and improve chronic heart failure induced by transverse aortic arch constriction in mice.
Methods:
Twenty-four male ICR mice were divided into the sham (n=6) and transverse aortic arch constriction groups (n=18) according to the random number table method. The transverse aortic arch constriction group underwent transverse aortic constriction surgery to establish models. After modeling, the transverse aortic arch constriction group was further divided into the model, captopril, and Laggerae Herba groups according to the random number table method, with six mice per group. The captopril (15 mg/kg) and Laggerae Herba groups (1.95 g/kg) received the corresponding drugs by gavage, whereas the sham operation and model groups were administered the same volume of ultrapure water by gavage once a day for four consecutive weeks. After treatment, the cardiac function indexes of mice in each group were detected using ultrasound. The heart mass and tibia length were measured to calculate the ratio of heart weight to tibia length. Hematoxylin and eosin staining were used to observe the pathological changes in myocardial tissue. Masson staining was used to observe the degree of myocardial fibrosis. Wheat germ agglutinin staining was used to observe the degree of myocardial cell hypertrophy. Prussian blue staining was used to observe the iron deposition in myocardial tissue. An enzyme-linked immunosorbent assay was used to detect the amino-terminal pro-brain natriuretic peptide (NT-proBNP) and glutathione (GSH) contents in mice serum. Colorimetry was used to detect the malondialdehyde (MDA) content in mice serum. Western blotting was used to detect the Nrf2, GPX4, SLC7A11, and ferritin heavy chain 1 (FTH1) protein expressions in mice cardiac tissue.
Results:
Compared with the sham group, in the model group, the ejection fraction (EF) and fractional shortening (FS) of mice decreased, the left ventricular end-systolic volume (LVESV) and left ventricular end-systolic diameter (LVESD) increased, the left ventricular anterior wall end-systolic thickness (LVAWs) and left ventricular posterior wall end-systolic thickness (LVPWs) decreased, the ratio of heart weight to tibia length increased, the myocardial tissue morphology changed, myocardial fibrosis increased, the cross-sectional area of myocardial cells increased, iron deposition appeared in myocardial tissue, the serum NT-proBNP and MDA levels increased, the GSH level decreased, and Nrf2, GPX4, SLC7A11, and FTH1 protein expressions in cardiac tissue decreased (P<0.05). Compared with the model group, in the captopril and Laggerae Herba groups, the EF, FS, and LVAWs increased, the LVESV and LVESD decreased, the ratio of heart weight to tibia length decreased, the myocardial cells were arranged neatly, the degree of myocardial fibrosis decreased, the cross-sectional area of myocardial cells decreased, the serum NT-proBNP level decreased, and the GSH level increased. Compared with the model group, the LVPWs increased, the iron deposition in myocardial tissue decreased, the serum MDA level decreased, and Nrf2, GPX4, SLC7A11, and FTH1 protein expressions in cardiac tissue increased (P<0.05) in the Laggerae Herba group.
Conclusion
Laggerae Herba improves the cardiac function of mice with chronic heart failure caused by transverse aortic arch constriction, reduces the pathological remodeling of the heart, and reduces fibrosis. Its mechanism may be related to Nrf2/SLC7A11/GPX4 pathway-mediated ferroptosis.
2.Correlation between ICAM-1, CD62P, and inflammatory factors and cerebral artery stenosis in patients with acute cerebral infarction
Yunying WU ; Tao HAN ; Yanbo CHENG ; Qian ZHAO
Journal of Public Health and Preventive Medicine 2025;36(5):89-92
Objective To investigate the correlation between levels of intercellular adhesion molecule-1 (ICAM-1), platelet surface P-selectin (CD62P), and inflammatory factors and cerebral artery stenosis in patients with acute cerebral infarction (ACI). Methods A total of 305 patients with ACI complicated with cerebral artery stenosis admitted to Zhongwu Hospital of Suqian City and Xinyi People's Hospital from January 2021 to December 2023 were selected as the research subjects. According to the degree of cerebral artery stenosis, they were divided into grade I group (stenosis degree<50%, n=85), grade II group (stenosis degree of 50%-75%, n=128), and grade III group (stenosis degree>75%, n=92). Sixty-eight ACI patients without cerebral artery stenosis during the same period were included in the reference group. The levels of serum inflammatory factors [C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8)], ICAM-1 and CD62P were compared among the four groups. Spearman analysis was used to analyze the correlation between each factor and degree of cerebral artery stenosis. Results The levels of CRP, TNF-α, IL-6, IL-8, ICAM-1 and CD62P in the grade I, II and III groups were higher than those in the reference group. The levels of these factors were higher in the grade II and III groups than those in the grade I group, while the levels of various factors were higher in the grade III group than those in the grade II group (P<0.05). Spearman analysis showed that CRP, TNF-α, IL-6, IL-8, ICAM-1, and CD62P were positively correlated with the degree of cerebral artery stenosis in patients with ACI complicated with cerebral artery stenosis (P<0.05). Conclusion The levels of serum inflammatory factors, ICAM-1 and CD62P are significantly correlated with cerebral artery stenosis degree in patients with ACI.
3.Improvement of neutral protease activity of Bacillus amyloliquefaciens LX-6 by combined ribosome engineering and medium optimization and its application in soybean meal fermentation.
Yifan ZHU ; Xinyi HUANG ; Tao HAN ; Jiteng WANG ; Xiaoping YU ; Zheng MA
Journal of Zhejiang University. Science. B 2025;26(8):805-812
Soybean meal (SBM) prepared by soybean crushing is the most popular protein source in the poultry and livestock industries (Cai et al., 2015) due to its economic manufacture, high protein content, and good nutritional value. Despite these benefits, SBM contains various antigen proteins such as glycinin and β-conglycinin, which account for approximately 70% of the total proteins of the SBM and reduce digestibility and damage intestinal function (Peng et al., 2018). Treating SBM with proteases (neutrase, alcalase, and trypsin) or fermentation can eliminate these antigen proteins (Contesini et al., 2018). Because of its safety and rapid growth cycle, Bacillus strains are considered ideal for the fermentation industry (Yao et al., 2021). SBM fermented by Bacillus yields products with high nutritional value and low levels of antinutritional factors (ANFs), stimulating research in this area (Yuan et al., 2017). Kumari et al. (2023) demonstrated that fermentation with Bacillus species effectively degrades antigen proteins and increases crude protein content. The degradation of antigen proteins relies on protease hydrolysis. Low protease production is the major obstacle hindering the widespread use of microbial fermentation techniques.
Bacillus amyloliquefaciens/metabolism*
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Fermentation
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Glycine max/metabolism*
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Soybean Proteins/metabolism*
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Peptide Hydrolases/metabolism*
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Ribosomes/metabolism*
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Globulins
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Antigens, Plant
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Seed Storage Proteins
4.Inhibition of zona incerta GABAergic neurons regulates lipopolysaccharide induced motor dysfunction in mice
Hongquan ZHANG ; Xinyi WANG ; Kun TONG ; Jie HAN ; Can GAO
Chinese Journal of Neuroanatomy 2024;40(3):347-352
Objective:By activating gamma-aminobutyric acid(GABA)neurons in zona incerta(ZI),we observed the alleviation of motor ability impairment in mice treated with lipopolysaccharide(LPS),and investigate the function of GABA neurons in the process of motor function impairment in mice with neuroinflammation.Methods:The central nervous system infection model of C57BU6 mice was eatablished by intraperitoneal injection of LPS.The motor function were detected by open field test and running wheel test in mice.The expression of c-Fos in ZI neurons and ionized calci-um binding adaptor molecule 1(Iba-1)in glial cells were detected by immunofluorescence staining.rAAV-DIO-hM3Dq-mCherry was bilaterally injected into ZI of adult male VGAT-Cre mice through the stereotaxic technique.After three weeks with the virus sufficiently expressing in the neurons,the neuroinflammation model was made by intrabitoneal injection of LPS,and GABAergic neurons were activated by intrabitoneal injection of N-oxyclozapine(CNO)30 min before behavioral tests.The motor ability in mice were detected by open field test and running wheel test.Results:The results of open field experiment and wheel experiment showed that the activity of mice in LPS group was significantly decreased(P<0.05)compared with the control group.The expression of ZI c-Fos positive protein in the brain of mice was significantly down-regulated with Iba-1 positive protein up-regulating in the ZI.The chemogenetic results showed that the activity of LPS mice was relieved with ZI GABAergic neurons being activated(P<0.05).Conclusion:The activity of ZI GABAergic neurons was significantly decreased and the motor ability was impaired in mice with neuroin-flammation in the brain.Chemogenetic activation of ZI GABAergic neurons significantly improved the motor ability of inflammatory mice.
5.Baihe Wuyaotang Ameliorates NAFLD by Enhancing mTOR-mediated Liver Autophagy
Rui WANG ; Tiantian BAN ; Lihui XUE ; Xinyi FENG ; Jiyuan GUO ; Jiaqi LI ; Shenghe JIANG ; Xiaolei HAN ; Baofeng HU ; Wenli ZHANG ; Naijun WU ; Shuang LI ; Yajuan QI
Chinese Journal of Experimental Traditional Medical Formulae 2024;30(7):66-77
ObjectiveTo investigate the therapeutic effect of Baihe Wuyaotang (BWT) on non-alcoholic fatty liver disease (NAFLD) and elucidate its underlying mechanism. MethodC57BL/6J mice were randomly assigned to six groups: normal control, model, positive drug (pioglitazone hydrochloride 1.95×10-3 g·kg-1), and low-, medium-, and high-dose BWT (1.3,2.5 and 5.1 g·kg-1). Following a 12-week high-fat diet (HFD) inducement, the mice underwent six weeks of therapeutic intervention with twice-daily drug administration. Body weight was monitored weekly throughout the treatment period. At the fifth week, glucose tolerance (GTT) and insulin tolerance (ITT) tests were conducted. Subsequently, the mice were euthanized for the collection of liver tissue and serum, and the subcutaneous adipose tissue (iWAT) and epididymal adipose tissue (eWAT) were weighed. Serum levels of total triglycerides (TG) and liver function indicators,such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were determined. Histological examinations, including oil red O staining, hematoxylin-eosin (HE) staining, Masson staining, and transmission electron microscopy, were performed to evaluate hepatic lipid deposition, pathological morphology, and ultrastructural changes, respectively. Meanwhile, Western blot and real-time quantitative polymerase chain reaction (Real-time PCR) were employed to analyze alterations, at both gene and protein levels, the insulin signaling pathway molecules, including insulin receptor substrate 1/2/protein kinase B/forkhead box gene O1 (IRS1/2/Akt/FoxO1), glycogen synthesis enzymes phosphoenolpyruvate carboxy kinase (Pepck) and glucose-6-phosphatase (G6Pase), lipid metabolism-related genes stearoyl-coA desaturase-1 (SCD-1) and carnitine palmitoyltransferase-1 (CPT-1), fibrosis-associated molecules α-smooth muscle actin (α-SMA), type Ⅰ collagen (CollagenⅠ), and the fibrosis canonical signaling pathway transforming growth factor-β1/drosophila mothers against decapentaplegic protein2/3(TGF-β1/p-Smad/Smad2/3), inflammatory factors such as interleukin(IL)-6, IL-8, IL-11, and IL-1β, autophagy markers LC3B Ⅱ/Ⅰ and p62/SQSTM1, and the expression of mammalian target of rapamycin (mTOR). ResultCompared with the model group, BWT reduced the body weight and liver weight of NAFLD mice(P<0.05, P<0.01), inhibited liver lipid accumulation, and reduced the weight of white fat: it reduced the weight of eWAT and iWAT(P<0.05, P<0.01) as well as the serum TG content(P<0.05, P<0.01). BWT improved the liver function as reflected by the reduced ALT and AST content(P<0.05, P<0.01). It improved liver insulin resistance by upregulating IRS2, p-Akt/Akt, p-FoxO1/FoxO1 expressions(P<0.05). Besides, it improved glucose and lipid metabolism disorders: it reduced fasting blood glucose and postprandial blood glucose(P<0.05, P<0.01), improved GTT and ITT(P<0.05, P<0.01), reduced the expression of Pepck, G6Pase, and SCD-1(P<0.01), and increased the expression of CPT-1(P<0.01). The expressions of α-SMA, Collagen1, and TGF-β1 proteins were down-regulated(P<0.05, P<0.01), while the expression of p-Smad/Smad2/3 was downregulated(P<0.05), suggesting BWT reduced liver fibrosis. BWT inhibited inflammation-related factors as it reduced the gene expression of IL-6, IL-8, IL-11 and IL-1β(P<0.01) and it enhanced autophagy by upregulating LC3B Ⅱ/Ⅰ expression(P<0.05)while downregulating the expression of p62/SQSTM1 and mTOR(P<0.05). ConclusionBWT ameliorates NAFLD by multifaceted improvements, including improving IR and glucose and lipid metabolism, anti-inflammation, anti-fibrosis, and enhancing autophagy. In particular, BWT may enhance liver autophagy by inhibiting the mTOR-mediated signaling pathway.
6.Astrocytes regulate glial scar formation in cerebral ischemic stroke
Ting YANG ; Zhibin DING ; Nan JIANG ; Hongxia HAN ; Miaomiao HOU ; Cungen MA ; Lijuan SONG ; Xinyi LI
Chinese Journal of Tissue Engineering Research 2024;28(1):131-138
BACKGROUND:Cerebral ischemic stroke is one of the main fatal and disabling diseases in the clinic,but only a few patients benefit from vascular recanalization in time,so it is urgent to explore new and effective therapy.As one of the critical pathological changes of ischemic stroke,the glial scar formed mainly by astrocytes is one major cause that hinders axonal regeneration and neurological recovery at the late stage of stroke. OBJECTIVE:To elucidate the pathological process and crucial signal regulatory mechanism of astrocytes in the formation of glial scar after ischemic stroke,as well as the potential therapeutic targets,to provide a theoretical reference for intervening astrocytic scar formation against ischemic stroke effectively,and novel strategies for promoting post-stroke rehabilitation. METHODS:The relevant articles published in CNKI,PubMed and Web of Science databases from 2010 to 2022 were retrieved.The search terms were"Ischemic stroke,Brain ischemi*,Cerebral ischemi*,Astrocyt*,Astroglia*,Glial scar,Gliosis,Astrogliosis"in Chinese and English.Finally,78 articles were included after screening and summarized. RESULTS AND CONCLUSION:(1)Astrocytes play an important role in the maintenance of central nervous system homeostasis.After ischemic stroke,astrocytes change from a resting state to an active state.According to the different severities of cerebral ischemic injury,astrocyte activation changes dynamically from swelling and proliferation to glial scar formation.(2)Mature astrocytes are stimulated to restart the cell cycle,then proliferate and migrate to lesions,which is the main source of the glial scar.Neural stem cells in the subventricular zone,neuron-glial antigen 2 precursor cells and ependymal precursor cells in the brain parenchyma can also differentiate into astrocytes.Endothelin-1,aquaporin 4,ciliary neurotrophic factor and connexins are involved in this process.In addition,chondroitin sulfate proteoglycan,as the main component of the extracellular matrix,forms the dense glial scar barrier with proliferated astrocytes,which hinders the polarization and extension of axons.(3)Activation or inhibition of crucial signal molecules involved in astrocyte activation,proliferation,migration and pro-inflammation functions regulate the glial scar formation.Transforming growth factor beta 1/Smad and Janus kinase/signal transducer and activator of transcription 3 are classical pathways related to astrogliosis,while receptor-interacting protein 1 kinase and glycogen synthase kinase 3β are significant molecules regulating the inflammatory response.However,there are relatively few studies on Smad ubiquitination regulatory factor 2 and Interleukin-17 and their downstream signaling pathways in glial scar formation,which are worthy of further exploration.(4)Drugs targeting astrogliosis-related signaling pathways,cell proliferation regulatory proteins and inflammatory factors effectively inhibit the formation of glial scar after cerebral ischemic stroke.Among them,the role of commonly used clinical drugs such as melatonin and valproic acid in regulating glial scar formation has been verified,which makes it possible to use drugs that inhibit glial scar formation to promote the recovery of neurological function in patients with stroke.(5)Considering the protective effects of glial scar in the acute phase,how to choose the appropriate intervention chance of drugs to maintain the protective effect of the glial scar while promoting nerve regeneration and repair in the local microenvironment is the direction of future efforts.
7.Combination of 1% platelet-rich plasma and bone marrow mesenchymal stem cells improves the recovery of peripheral nerve injury
Ruiqin FENG ; Na HAN ; Meng ZHANG ; Xinyi GU ; Fengshi ZHANG
Chinese Journal of Tissue Engineering Research 2024;28(7):985-992
BACKGROUND:Platelet-rich plasma has been shown to enhance the viability and the pro-angiogenesis capacity of mesenchymal stem cells.Extracellular vesicles are one of the key mediators for mesenchymal stem cells to exert their effects,but currently,it is unclear whether platelet-rich plasma affects the functions of extracellular vesicles. OBJECTIVE:To investigate the effects of platelet-rich plasma on the function of extracellular vesicles from bone marrow mesenchymal stem cells,verify whether platelet-rich plasma can be used as an adjuvant to enhance the healing effects of bone marrow mesenchymal stem cells on repairing the peripheral nerve injury. METHODS:For in vitro study,bone marrow mesenchymal stem cells were cultured under normal conditions and with 1%platelet-rich plasma.The ultracentrifugation was used to extract the extracellular vesicles produced by bone marrow mesenchymal stem cells cultured under normal conditions(EVs-nor)or the condition supplemented with 1%platelet-rich plasma(EVs-prp).Extracellular vesicles were used to incubate with Schwann cells.The EdU assay,western blot assay,qPCR and light microscopy photography were performed to examine the effects of EVs-nor and EVs-prp on Schwann cell reprogramming,which was characterized by cell proliferation,c-Jun expression,reprogramming-associated gene expression and cell morphology.For in vivo study,the model of sciatic nerve injury in rats was established.Bone marrow mesenchymal stem cells were grafted with or without 1%platelet-rich plasma into the injured rat sciatic nerve using a chitin nerve conduit.Eight weeks after the surgery,the recovery was assessed by histological and functional indexes,including regenerated nerve fiber density,gastrocnemius wet weight ratio and sciatic function index. RESULTS AND CONCLUSION:(1)Compared with EVs-nor,EVs-prp was stronger in promoting Schwann cell proliferation.The gene expressions of c-Jun and GDNF were significantly upregulated in EVs-prp treated Schwann cells.The morphology of Schwann cells was significantly longer in EVs-prp group than that in EVs-nor group,indicating that EVs-prp had a stronger ability to stimulate Schwann cell reprogramming than EVs-nor.(2)Sciatic nerve injury animal experiment results revealed that grafting mesenchymal stem cells along with platelet-rich plasma into the injured sciatic nerve showed the best recovery compared with grafting mesenchymal stem cells or platelet-rich plasma alone,demonstrated by the significantly improved density of nerve fibers,gastrocnemius wet weight ratio,and sciatic function index.(3)These results suggested that platelet-rich plasma improved the function of bone marrow mesenchymal stem cell-derived extracellular vesicles and could be served as a practical and feasible preparation to synergize with bone marrow mesenchymal stem cells to improve peripheral nerve repair.
8.Self Precipitation Analysis of Erhuang Powder and Its Effect on HeLa Cells
Xinyi WANG ; Shuyu ZHAO ; Xiufeng YU ; Feng GUAN ; Weinan LI ; Fengjuan HAN ; Yanhong WANG
Chinese Journal of Modern Applied Pharmacy 2024;41(12):1604-1614
OBJECTIVE
To explore the self precipitation source of Erhuang powder, determine the content of related components and its efficacy on HeLa cells.
METHODS
Bifurcation study to identify the main compatibility of precipitating. The self precipitation, supernatant and extract of Erhuang powder were analyzed by UHPLC-Q-Exactive MS. The main compounds in Coptidis Rhizoma and Catechu, catechin, epicatechin, epicberberine, coptisine, berberine and palmatine were selected as controls. A analysis method of UHPLC for self precipitation, supernatant and extract of Erhuang powder was established and the related components were quantitatively determined. The effects of self precipitation, supernatant and extract on HeLa cells were evaluated by MTT method and flow cytometry.
RESULTS
A slight flocculation precipitate appeared when the decoction of Erhuang powder was mixed in pairs, while a large amount of flocculation appeared when the decoction of Coptidis Rhizoma and Catechu water was mixed. The self precipitation, supernatant and extract samples contained 39 compounds, which were mainly alkaloids and phenolic acids. The contents of catechin and berberine in the 6 index components were mostly, which accounted for 73.56% of the total content of the index components in self precipitation and 61.89% of the total content of the index components in extract. Inhibition effect on HeLa cells: extract ≈ self precipitation > supernatant, and inducing apoptosis: self precipitate ≈ extract, supernatant had no apoptosis-inducing effect.
CONCLUSION
Coptidis Rhizoma-Catechu is the main compatible formula for precipitation formation. The self precipitation and extracts of Erhuang powder are mainly alkaloids and phenolic acids, among which berberine and catechin are high in content and can be used as representative components. The effect of self-precipitation and extract on HeLa cells was better than that of supernatant. This basically indicates that the self precipitation components and pharmacological effects of Erhuang powder are similar to those of the extract.
9.Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources
Xiao HAN ; Xinyi GONG ; Beibei MIAO ; Huan XING ; Zeliang LIU ; Pengfang GAO ; Yuelong LI ; Jiachen LI ; Yating TANG ; Yanlei GE ; Aiying DONG ; Juan LI
Chinese Journal of Preventive Medicine 2024;58(6):891-897
To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and r df_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, l mb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.
10.Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources
Xiao HAN ; Xinyi GONG ; Beibei MIAO ; Huan XING ; Zeliang LIU ; Pengfang GAO ; Yuelong LI ; Jiachen LI ; Yating TANG ; Yanlei GE ; Aiying DONG ; Juan LI
Chinese Journal of Preventive Medicine 2024;58(6):891-897
To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and r df_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, l mb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.


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