1.Effect and mechanism of different concentrationsof resveratrol on hypermucinous Klebsiella pneumoniae
YU Feng ; XU Xianyun ; YANG Xiaojun
China Tropical Medicine 2024;24(5):566-
Abstract: Objective To investigate the effects and mechanisms of resveratrol on in vitro growth and biofilm formation of hypermucinous Klebsiella pneumoniae(HMKP), so as to provide a preliminary theoretical basis for the development of new antimicrobial drugs. Methods Clinical isolates of Klebsiella pneumoniae, non-repetitive, collected from March to October 2023, were identified for species and sensitivity to common antimicrobials using the VITEK-2 compact automatic microbial identification system. The mucous characteristics of the strains were assessed via a string test, and the broth microdilution method determined the minimum inhibitory concentration (MIC) of resveratrol. The effects of different concentrations of resveratrol on the growth of hypermucinous Klebsiella pneumoniae were observed by the bacterial growth curve method, and the effects of different concentrations of resveratrol on HMKP biofilm were determined by the crystal violet staining method. Real-time quantitative reverse transcription PCR (RT-qPCR) was used to detect the expression levels of virulence-related genes (aerobactin, rmpA, and mrkD) in HMKP. Data plotting and analysis were performed using GraphPad Prism 9.0. Results A total of 122 strains of Klebsiella pneumoniae were collected, with 29 strains testing positive in the string test (HMKP). Among these, 26 strains were allergic to commonly antimicrobial drugs, such as cephalosporins and their enzyme inhibitors, quinolones, and aminoglycosides, while 3 strains were identified as carbapenem-resistant hypermucinous Klebsiella pneumoniae (HM-CRKP). The minimum inhibitory concentration (MIC) of resveratrol for all HMKP strains exceeded 512 μg/mL. Resveratrol concentrations of 256 μg/mL and 128 μg/mL significantly reduced the growth capacity and biofilm formation capacity of HMKP (P<0.05) and decreased the expression levels of virulence-related genes rmpA and mrkD. Conclusions Resveratrol can inhibit the growth and biofilm formation of HMKP. The mechanism may be related to the downregulation of virulence-related genes expression, specifically rmpA and mrkD.
2.Experimental study of three different β-receptor blockers in treatment on murine hemangioendothelioma
Xianyun XU ; Qiongjun XIE ; Wei PENG ; Huiting NING ; Juncheng WEN ; Tao WANG ; Liangwen MA ; Yanbin HAO ; Qian LIU
Chinese Journal of Immunology 2016;32(8):1118-1122
Objective:To comparison of three different beta blockers on murine hemangioma (EOMA cells) cells in vitro and in vivo effects.Preliminary study on the therapeutic effect of propranolol on vascular tumor in mice and possible mechanisms , provide a reference for beta blockers in the treatment of infantile hemangioma .Methods: Comparative study on the effects of three kinds of different β-receptor blockers---metoprolol, propranolol and butoxamine , on the proliferation and apoptosis of Mouse Hemangioendothelioma Endothelial cell (EOMA cells) was conducted in vitro.EOMA cells were cultured in vitro,randomly divided into different groups,propranolol and timolol were added into the medium respectively ,after 24 h intervention.MTT assay and acridine orange staining assay were conducted respectively to detect cell viability and apoptosis level .EOMA cells were transplanted into nude mice in vivo.Tumor volume growth to 100 mm3 ,animals were randomly divided into 4 groups respectively ,the control group ,metoprolol group,Bhutto Samin group and propranolol group ,drug group according to 2 mg/( kg? d) oral gavage ,control group were given an equal volume of saline ( NS ) , every two days measurement tumor volume size .Serum levels of tumor necrosis factor alpha ( TNF-α) and vascular endothelial growth factor ( VEGF ) were detected by enzyme linked immunosorbent assay ( ELISA ) in the end of the experiment.Results:For propranolol,after 24 h treatment,significant differences of cell viability and apoptosis were noted (P<0.05) at the concentration of 50 μmol/L,while continuing to increase to 800 μmol/L,the cell survival rate decreased sharply to close to 10%. Acridine orange staining at the 50 μmol/L group after 24 h revealed many apoptotic cells .For metoprolol and butoxa mine ,significant differences of cell viability and apoptosis were noted ( P<0.05 ) at the concentration of 100 μmol/L,while continuing to increase to 800μmol/L,the cell survival rate decreased sharply to close to 20%.It was significantly higher than propranolol group at the same concentration ( P<0.05 ) .It showed a similar trend in acridine orange staining .In vivo experiments showed that the end of the experiment of metoprolol , butoxamine group and propranolol drugs in mice tumor volume , respectively ( 1 642.8 ±89.3 ) , ( 1 529.3 ± 119.1) and (752.7±46.5)mm3,significantly lower than the control group of mice tumor volume of (2 023.3±123.0) mm3(P<0.001).Metoprolol,butoxamine mice and propranolol drugs group ,serum VEGF levels for (606.5±105.8 ) pg/ml,(534.3±243.2 ) pg/ml and (420.1±123.7) pg/ml, significantly lower than the PBS control group [(825.8±145.7) pg/ml,(P<0.05)],the TNF alpha result was followed by(301.3±62.3) pg/ml,(305.1±53.8) pg/ml and (288.8±59.5) pg/ml,significantly lower than the normal control group [(444±100.4) pg/ml,P<0.05].Conclusion:Three kinds of beta-blockers can effectively inhibit EOMA cells proliferation and induce apoptosis in vitro, the role of propranolol more significantly than butoxamine and metoprolol .Three kinds of beta blockers restrain the growth of the hemangioma in vivo ,in which the inhibitory effect of propranolol is stronger than the metoprolol and butoxa mine.Three kinds of beta blockers can lower the levels of VEGF and TNF-αin vivo.Indicating that propranolol on vascular tumor in mice may be one of the mechanisms of β1 and β2 receptor synergy effect and its mechanism in the treatment of hemangioma may be associated with VEGF and TNF-α.
3.Influencing factors and epidemiological characteristics of common pneumonia pathogens and severe pneumonia in preschool children in Xining Area
Xianyun YU ; Fangjing WANG ; Jingjing XU ; Jinmei HE ; Chongzhi XU
Journal of Public Health and Preventive Medicine 2025;36(4):69-72
Objective To explore the epidemic characteristics of common pneumonia pathogens in preschool children in Xining area and analyze the influencing factors of progression to severe pneumonia. Methods A total of 522 preschool children with pneumonia who were treated in our hospital from May 2021 to March 2024 were retrospectively selected as the research subjects. Sputum samples from children were taken to identify the pathogens and analyze their pathogenic epidemic characteristics.According to the diagnostic criteria in the 2019 version of “Standards for the Diagnosis and Treatment of Community-Acquired Pneumonia in Children”, determine whether it is severe pneumonia, and collect the clinical data of the children.Logistic regression was used to analyze the influencing factors of the progression of common pneumonia to severe pneumonia. Results Among the 522 children with pneumonia, 522 cases were infected with pathogens, of which 447 cases were single infection (85.63%), 75 cases were mixed infection (14.36%). A total of 597 pathogens were detected, including 257 viruses (43.05%), 240 bacteria (40.20%), 68 mycoplasma pneumoniae (11.39%) and 32 chlamydia pneumoniae (5.36) . The detection rates of Streptococcus pneumoniae (149, 24.96%) and respiratory syncytial virus (118, 19.77%) were higher. Logistic regression results showed that length of hospital stay (OR=2.235, 95% CI: 1.552-3.439), ICU admission (OR=2.426, 95% CI: 1.769-3.881), intestinal microbiota disorder (OR=1.626, 95% CI: 1.335-2.842), multi-drug resistance (OR=2.086, 95%CI 1.417-2.905), mixed infection (OR=3.134, 95% CI : 2.217-8.857), nutritional risk (OR=2.783, 95% CI: 2.038-4.764), CRP (OR=2.589, 95% CI: 1.805-4.117), PCT (OR=1.486, 95%CI: 1.077-1.649), and white blood cells (OR=1.329, 95% CI: 1.021-1.536) were all associated with the risk of severe pneumonia (P<0.05). Conclusion The main pathogens of pneumonia in preschool children in Xining are Streptococcus pneumoniae and respiratory syncytial virus. Paying attention to the treatment of children with intestinal disorders, multiple infections, and malnutrition is of great significance to improve the progression of pneumonia.