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1.
Food Chem ; 308: 125682, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31655479

RESUMO

In this work, a multifunctional food packaging composite coating with transparent, biodegradable, antifogging and antibacterial properties was designed and fabricated by quaternary ammonium salt modified chitosan (HACC) and poly (vinyl alcohol) (PVA) via a facile and environment-friendly solution casting method. A simple quaternization modification enabled the coating simultaneously to achieve excellent antifogging and antibacterial functions. The excellent antifogging property of the HACC/PVA composite coating was attributed to the strong water absorbency of quaternary ammonium chitosan and PVA. A nearly 98% transmittance ratio of coated glasses was achieved during antifogging test. In addition, the inhibition rate of the HACC/PVA composite coating kill against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Botrytis cinerea were up to ~99%. The antibacterial effect was demonstrated by each group of strawberries after storage for 1, 3, 5 days. The multifunctional coating has broad prospects in the application of fruit and vegetable packaging.


Assuntos
Compostos de Amônio/química , Antibacterianos/farmacologia , Quitosana/farmacologia , Embalagem de Alimentos , Quitosana/química , Escherichia coli/efeitos dos fármacos , Compostos de Amônio Quaternário , Staphylococcus aureus/efeitos dos fármacos
2.
J Colloid Interface Sci ; 559: 197-205, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31627143

RESUMO

Mesoporous silica nanoparticle (MSN) demonstrates great potentials as a loading platform for bactericidal agents, but may be limited by its application form of bulk or powder. Herein, we developed MSN surface-enriched composite membranes with remarkable photodynamic antimicrobial activities via a facile electrospinning method. The mixture of zein and polycaprolactone (PCL) was served as the polymeric matrix, while the methylene blue (MB) loaded MSN was modified by trichloro (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane (THFS) and acted as reactive oxygen species (ROS) generator to exert their antimicrobial performances. Owing to its low surface energy, the fluorinated MSN tended to be enriched on the surface of the nanofiber, hence significantly enhancing the ROS generation. Moreover, benefiting from the surface enrichment of the fluorinated nanoparticles, the composite membrane displayed obvious surface hydrophobicity and exhibited discernible bacterial repellency. Subsequently, upon visible light (660 nm) irradiation, the composite membrane demonstrated remarkable photodynamic antibacterial activities against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) but without essential detrimental impacts on the mammalian cells. We envision that this self-enriched MSN composite membrane may find broad applications in bacterial infection-resistant areas.


Assuntos
Anti-Infecciosos/química , Azul de Metileno/química , Nanopartículas/química , Fotoquimioterapia/métodos , Dióxido de Silício/química , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fibroblastos/citologia , Flúor/química , Interações Hidrofóbicas e Hidrofílicas , Luz , Camundongos , Poliésteres/química , Porosidade , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Zeína/química
3.
J Colloid Interface Sci ; 559: 313-323, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675662

RESUMO

Antibiotic resistance is a common phenomenon observed during treatment with antibacterials. Use of nanozymes, especially those with synergistic enzyme-like activities, as antibacterials could overcome this problem, but their synthesis is limited by their high cost and/or complex production process. Herein, vanadium oxide nanodots (VOxNDs) were prepared via a one-step bottom-up ethanol-thermal method using vanadium trichloride as the precursor. VOxNDs alone possess bienzyme mimics of peroxidase and oxidase. Accordingly, highly efficient antibacterials against drug-resistant bacteria can be obtained through synergistic catalysis; the oxidase-like activity decomposes O2 to generate superoxide anion radical (O2-) and hydroxyl radicals (OH), and the intrinsic peroxidase-like activity can further induce the production of OH from external H2O2. Consequently, H2O2 concentration could decrease up to four magnitude orders with VOxNDs to achieve an antibacterial efficacy similar to that of H2O2 alone. Wound healing in vivo further confirms the high antibacterial efficiency, good biocompatibility, and application potential of the synergistic antibacterial system due to the "nano" structure of VOxNDs. The method of synthesis of nanodot antibacterials described in this paper is inexpensive, and the results of this study reveal the multi-enzymatic synergism of nanozymes.


Assuntos
Antibacterianos/química , Nanopartículas Metálicas/química , Óxidos/química , Compostos de Vanádio/química , Cicatrização/efeitos dos fármacos , Animais , Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Catálise , Sobrevivência Celular/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Células HeLa , Células Endoteliais da Veia Umbilical Humana , Humanos , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Peroxidases/metabolismo , Ratos Sprague-Dawley , Staphylococcus aureus/efeitos dos fármacos
4.
J Colloid Interface Sci ; 558: 47-54, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31580954

RESUMO

The unique antibacterial characteristics of Ag nanomaterials offer a wide potential range of applications, but achieving rapid and durable antibacterial efficacy is challenging. This is because the speed and durability of the antibacterial function make conflicting demands on the structural design: the former requires the direct exposure of Ag to the surrounding environment, whereas the durability requires Ag to be protected from the environment. To overcome this incompatibility, we synthesize sandwich-structured polydopamine shells decorated both internally and externally with Ag nanoparticles, which exhibit prompt and lasting bioactivity in applications. These shells are biocompatible and can be used in vivo to counter bacterial infection caused by methicillin-resistant Staphylococcus aureus superbugs and to inhibit biofilm formation. This work represents a new paradigm for the design of composite materials with enhanced antibacterial properties.


Assuntos
Antibacterianos/química , Materiais Biocompatíveis/química , Indóis/química , Nanopartículas Metálicas/química , Polímeros/química , Prata/química , Animais , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Escherichia coli/efeitos dos fármacos , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Ratos , Ratos Sprague-Dawley
5.
Arch Insect Biochem Physiol ; 103(1): e21626, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31562754

RESUMO

Insects can produce various antimicrobial peptides (AMPs) upon immune stimulation. One class of AMPs are characterized by their high proline content in certain fragments. They are generally called proline-rich antimicrobial peptides (PrAMPs). We previously reported the characterization of Spodoptera litura lebocin-1 (SlLeb-1), a PrAMP proprotein. Preliminary studies with synthetic polypeptides showed that among the four deductive active fragments, the C-terminal fragment SlLeb-1 (124-158) showed strong antibacterial activities. Here, we further characterized the antibacterial and antifungal activities of 124-158 and its four subfragments: 124-155, 124-149, 127-158, and 135-158. Only 124-158 and 127-158 could agglutinate bacteria, while 124-158 and four subfragments all could agglutinate Beauveria bassiana spores. Confocal microscopy showed that fluorescent peptides were located on the microbial surface. Fragment 135-158 lost activity completely against Escherichia coli and Staphylococcus aureus, and partially against Bacillus subtilis. Only 124-149 showed low activity against Serratia marcescens. Negative staining, transmission, and scanning electron microscopy of 124-158 treated bacteria showed different morphologies. Flow cytometry analysis of S. aureus showed that 124-158 and four subfragments changed bacterial subpopulations and caused an increase of DNA content. These results indicate that active fragments of SlLeb-1 may have diverse antimicrobial effects against different microbes. This study may provide an insight into the development of novel antimicrobial agents.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Insetos/farmacologia , Spodoptera/química , Animais , Peptídeos Catiônicos Antimicrobianos/química , Bacillus subtilis/efeitos dos fármacos , Beauveria/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Proteínas de Insetos/química , Serratia marcescens/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
6.
Food Chem ; 308: 125633, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31644968

RESUMO

The objective of this study was to evaluate the in vitro antimicrobial and antioxidant activities of different bran extracts and concentrations, and their influence on the parameters of a mayonnaise-type emulsion. To that end, first ethanol and then water were used to extract two rice bran extracts (RBE) from rice bran. Both these extracts were then added at two different concentrations (0.5 and 2%) to the emulsions that were subsequently analysed after seven days under two different storage temperatures, 4 °C and 20 °C. The antioxidant and antimicrobial ability of the extracts were evaluated, along with a control and a synthetic antioxidant. Results indicate the positive effect of rice bran extracts as additives in the food matrix. Ethanolic rice bran extract (EE) at 2% decreased the oxidation as well as mould and yeast proliferation and preserved the emulsion structure, while the other treatments acted in a similar way although their effect was less pronounced.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Oryza/química , Extratos Vegetais/farmacologia , Antibacterianos/química , Antioxidantes/química , Condimentos , Emulsões , Escherichia coli/efeitos dos fármacos , Listeria/efeitos dos fármacos , Oxirredução , Extratos Vegetais/química
7.
Bratisl Lek Listy ; 120(12): 935-940, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31855054

RESUMO

OBJECTIVES: We focused on detecting the most frequent resistance mechanisms in selected multidrug-resistant (MDR) strains and determining their antimicrobial resistance. BACKGROUND: MDR pathogens pose urgent public health threat due to limited treatment options, rigorous control measures and significant mortality. METHODS: We confirmed extended-spectrum ß-lactamase (ESBL) and carbapenemase producing Enterobacteriaceae through guidelines, as well following ß-lactamases: AmpC by cloxacillin, class A carbapenemase with phenylboronic acid, class B metallo-ß-lactamase with ethylenediaminetetraacetic acid. Multilocus sequence typing was used to investigate 20 Escherichia coli strains. RESULTS: Overall 205 mostly ESBL Escherichia coli demonstrated resistance against amikacin (4.7 %), tigecycline (1.2 %), and no resistance to ceftazidime/avibactam, meropenem, nitrofurantoin and fosfomycin. Out of 41 Klebsiella species (spp.), 37 (90.2 %) showed carbapenemase activity, 13 (35.1 %) of class A and 24 (64.9 %) of class B. Resistance was following: meropenem 66.7 %, tigecyclin 10.2 % and colistin 0 %. From Enterobacter spp. 21 strains, 14 (66.7 %) were ESBL, 5 produced ESBL and/or AmpC and 2 were MDR. We ascertained 14 (70 %) E. coli sequence type - ST131. CONCLUSIONS: The study revealed various resistance mechanisms in concert with different agents and association of specific ST131 within E. coli. These characteristics considerably contribute to emergence of antimicrobial resistance (Tab. 4, Ref. 30).


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriaceae/enzimologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Klebsiella pneumoniae/efeitos dos fármacos , beta-Lactamases/metabolismo , Adulto , Idoso , Proteínas de Bactérias/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Farmacorresistência Bacteriana , Enterobacteriaceae/classificação , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , beta-Lactamases/genética
8.
J Photochem Photobiol B ; 200: 111650, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31698288

RESUMO

The biosynthesis of ZnO nanoparticles was synthesized by biogenic reduction of applied Cucurbita seed extract. The powder X-ray diffraction pattern displayed the high crystalline nature of synthesized ZnO nanoparticles and the crystallite size was calculated at 35 nm range. The Fourier Transform Infra-Red study revealed the functional groups of biogenic reduction and vibrational bands present in the synthesized nanoparticles. The UV-Visible analysis explained the SPR absorption peak at 371 nm. The Photoluminescence study revealed the strong red shoulder emission peak at 665 nm. The particle size analyzer displayed the particle size occupies majorly on 45-65 nm. The SEM analysis pointed the ZnO nanoparticles under rod, rectangular and hexagonal shapes were procured. The EDAX spectrum also mapping exposed the purity of formed ZnO nanoparticles with just Zn and O peaks. The HRTEM analysis exposed the hexagonal shape wurtzite structure ZnO particles formation. The physiochemical analysis revealed general nature of Cucurbita seed powder moreover which explained the phytochemicals involved in biogenic reduction of ZnO nanoparticles. The formed ZnO nanoparticles exhibited good antibacterial activity on E. coli, Bacillus pumilus, and Salmonella typhi bacteria. The cytotoxicity study stated the good toxicity on E. coli AB 1157. The antifungal activity showed a better effect on Aspergillus flavus and Aspergillus niger fungi. The antioxidant activity clarified the good free radical scavenging action. The anti larvicidal activity expressed a better impact on Culex tritaeniorhynchus mosquito larvae.


Assuntos
Cucurbita/química , Culex/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Extratos Vegetais/química , Óxido de Zinco/química , Animais , Antibacterianos/biossíntese , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Aspergillus niger/efeitos dos fármacos , Cucurbita/metabolismo , Culex/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Química Verde , Larva/efeitos dos fármacos , Nanopartículas Metálicas/química , Tamanho da Partícula , Sementes/química , Sementes/metabolismo
9.
J Photochem Photobiol B ; 201: 111651, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31683166

RESUMO

Designing biomimetic biomaterials influenced by the common complex structure of hard tissues is yet a test these days. The control of bio-mineralization procedure onto biomaterials should be assessed before the use in medical applications. Coming to the bone rejuvenation applications, this work assessed the in vitro antibacterial activity and interacting between osteoblast cells (MG63) on poly (hydroxypropyl methacrylate) (PHPMA) cryogel consolidated with Zn/Ce substituted hydroxyapatite (MHAp) nanocomposite (PHPMA/MHAp). Osteoblast cell multiplication, morphology, and metabolic action were assessed through various conventions. The functional group, texture, mechanical properties, and protein adsorption profiles of the fabricated nanocomposite were analyzed by the FTIR, XRD, SEM, and mechanical examinations, respectively. The bacterial activity of nanocomposites was additionally assessed against E. coli and S. aureus microorganisms, individually. Nanocomposite advanced endo-chondral ossification at the messed up parts of the bone deformity than cryogel did. These results recommend that PHPMA/MHAp nanocomposites joined the good innate properties of each polymer and bioceramic, giving a mechanically powerful, cell-responsive, and permeable stage for hard tissue applications.


Assuntos
Criogéis/química , Durapatita/química , Fraturas do Fêmur/terapia , Nanocompostos/química , Nanopartículas/química , Animais , Regeneração Óssea/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Cério/química , Modelos Animais de Doenças , Escherichia coli/efeitos dos fármacos , Fraturas do Fêmur/patologia , Nanocompostos/uso terapêutico , Nanocompostos/toxicidade , Polímeros/química , Ratos , Staphylococcus aureus/efeitos dos fármacos , Engenharia Tecidual , Zinco/química
10.
Chem Commun (Camb) ; 55(87): 13104-13107, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612170

RESUMO

We designed a few polymyxin derivatives which exhibit broad-spectrum antimicrobial activity. Lead compound P1 could disrupt bacterial membranes rapidly without developing resistance, inhibit biofilms formed by E. coli, and exhibit excellent in vivo activity in an MRSA-infected thigh burden mouse model.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Polimixinas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Conformação Molecular , Polimixinas/síntese química , Polimixinas/química
11.
J Agric Food Chem ; 67(45): 12393-12401, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31596571

RESUMO

Accumulation of toxic copper in soil and development of copper-resistant pests are emerging challenges currently faced by the agricultural community worldwide. As an alternative, we have developed a ternary zinc chelate solution (TSOL) pesticide where zinc ions are the primary active ingredient. The material is composed of zinc, urea, and hydrogen peroxide. Urea was chosen as it is widely used as a plant fertilizer and can also bind to both zinc and hydrogen peroxide. No phytotoxicity was observed with TSOL on Meyer lemon (Citrus × meyeri) seedlings at a field spray rate of 800 µg/mL Zn metal concentration. Antimicrobial studies showed that TSOL exhibited improved killing efficacy against Escherichia coli and Xanthomonas alfalfae compared to Zn ions alone. Citrus canker field trials in a grapefruit (Chrysopelea paradisi) grove over three years showed that TSOL provided comparable disease protection to copper products at an equivalent or lower metal content.


Assuntos
Antibacterianos/química , Citrus/microbiologia , Peróxido de Hidrogênio/química , Doenças das Plantas/microbiologia , Ureia/química , Zinco/química , Zinco/farmacologia , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Peróxido de Hidrogênio/farmacologia , Folhas de Planta/microbiologia , Ureia/farmacologia , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
12.
Mymensingh Med J ; 28(4): 767-772, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31599239

RESUMO

Evaluation of the in vitro antibacterial activity of the ethanolic extract isolated from Cinnamomum zeylanicum bark against two food borne pathogens, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. This experimental study was carried out in the department of Pharmacology & Therapeutics in collaboration with the department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2017 to July 2018. The antibacterial activity was tested at different concentrations of extracts of spice by using disc diffusion method. The extracts were prepared by using a solvent ethanol. The test microorganisms were also tested for their activity against a standard antibiotic Amikacin (500mg) by disc diffusion method and the result was compared with that of ethanolic extracts. Cinnamon had inhibitory activity against both Staphylococcus aureus and Escherichia coli. The ethanolic extracts were more effective against Staphylococcus aureus than E. coli. Staphylococcus aureus showed activity from 60% conc. (zone of inhibition 17mm) where E. coli from 80% conc. (ZOI 18mm). Maximum zone of inhibition was 26mm for both the test organisms. This result was also compared to those obtained against a standard antibiotic Amikacin where extract produced wider zone of inhibition of 26mm as compared to Amikacin for both test organisms. The present study showed that ethanolic extract of cinnamon demonstrated stronger antimicrobial effect against food borne pathogens.


Assuntos
Antibacterianos/toxicidade , Cinnamomum zeylanicum , Escherichia coli/efeitos dos fármacos , Extratos Vegetais/toxicidade , Staphylococcus aureus/efeitos dos fármacos , Bangladesh , Etanol , Microbiologia de Alimentos , Humanos
13.
Mymensingh Med J ; 28(4): 779-791, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31599241

RESUMO

Evaluation of the in vitro antibacterial activity of aqueous and ethanolic extracts isolated from Clove (Syzygium aromaticum) buds against three food borne pathogens, gram-positive Staphylococcus aureus and gram-negative Escherichia coli & Pseudomonas aeruginosa. This interventional study was carried out during the period of July 2018 to June 2019 in the Department of Pharmacology and Therapeutics with the collaboration of Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. The antibacterial activity was tested at different concentrations of both extracts of spice by using disc diffusion & broth dilution method. The extracts were prepared by using solvents aqueous & ethanol. The test microorganisms were also tested for their activity against a standard antibiotic Gentamicin (80mg) by broth dilution method and the result was compared with that of Aqueous and Ethanolic extracts. Aqueous and ethanolic extracts of clove had inhibitory activity against the test bacteria. Among different concentrations of the ACE, 500µg/ml & above concentration showed inhibitory effect against Staphylococcus aureus & Escherichia coli and 700µg/ml & above concentration showed inhibitory effect against Pseudomonas aeruginosa. In case of ECE, 500µg/ml & above concentration showed inhibitory effect against aforesaid bacteria. In disc diffusion method, S. aureus was found to be most susceptible to ACE (30.5mm) & Pseudomonas aeruginosa was found to be most susceptible to ECE (38mm). Minimum inhibitory concentrations (MIC) of ECE were lower than ACE for the test bacteria except Staphylococcus aureus where MICs of ACE & ECE were the same. This result was also compared against a standard antibiotic Gentamicin where the MICs of Gentamicin were lower in comparison to MICs of ACE & ECE. The present study showed that aqueous and ethanolic extracts of Clove demonstrated antibacterial effects against food borne pathogens.


Assuntos
Antibacterianos/toxicidade , Extratos Vegetais/toxicidade , Syzygium , Bangladesh , Escherichia coli/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
14.
N Engl J Med ; 381(21): 2043-2050, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31665575

RESUMO

Fecal microbiota transplantation (FMT) is an emerging therapy for recurrent or refractory Clostridioides difficile infection and is being actively investigated for other conditions. We describe two patients in whom extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli bacteremia occurred after they had undergone FMT in two independent clinical trials; both cases were linked to the same stool donor by means of genomic sequencing. One of the patients died. Enhanced donor screening to limit the transmission of microorganisms that could lead to adverse infectious events and continued vigilance to define the benefits and risks of FMT across different patient populations are warranted.


Assuntos
Bacteriemia/etiologia , Disbiose/terapia , Escherichia coli/isolamento & purificação , Transplante de Microbiota Fecal/efeitos adversos , Fezes/microbiologia , Idoso , Bacteriemia/microbiologia , Farmacorresistência Bacteriana , Disbiose/etiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Evolução Fatal , Encefalopatia Hepática/complicações , Encefalopatia Hepática/terapia , Humanos , Masculino , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/terapia , beta-Lactamases/metabolismo
15.
J Agric Food Chem ; 67(45): 12584-12589, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31640344

RESUMO

Lysozyme has emerged to be a promising alternative to traditional antibiotics to deal with the increasing antibiotic resistance of bacteria. However, its application is hampered by its inferior bactericidal activity against Gram-negative bacteria. To address this problem, a novel "enzyme-cascade fluorescent high-throughput screening (HTS) method" was designed and constructed based on detection of fluorescence resonance energy transfer (FRET) and enzyme-cascade reaction of lysozyme and protease. As a proof of concept, site-saturation mutagenesis libraries targeting at residues of the unstructured stretch at the N-terminus of Antheraea pernyi lysozyme were constructed and screened by the proposed HTS method. The isolated lysozyme variants proved to exhibit higher antibacterial activity against Escherichia coli K12, demonstrating the significance of this region for the bactericidal function of lysozyme. The presented cell-based fluorescent HTS method is a new tool for screening lysozyme variants with improved bactericidal efficacy against Gram-negative bacteria and for exploring the sequence-structure-function relationship of lysozyme.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Transferência Ressonante de Energia de Fluorescência/métodos , Ensaios de Triagem em Larga Escala/métodos , Muramidase/química , Muramidase/farmacologia , Animais , Escherichia coli/crescimento & desenvolvimento , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Mariposas/química , Mariposas/genética , Mariposas/metabolismo
16.
Soft Matter ; 15(38): 7686-7694, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31498364

RESUMO

We report a simple and facile self-assembly approach to fabricate polyelectrolyte complex (PEC) hydrogel films with positively charged chitosan (CS) and negatively charged heparin sodium (HS) by combining hydrogen bonding and electrostatic interactions. The CS/HS hydrogel films exhibited excellent tensile strength and toughness, good self-recovery ability, superior water absorbency, and pH-dependent surface charge characteristics. The gelation mechanism was investigated by zeta potential measurements. The CS/HS hydrogel films exhibited high antibacterial efficacy against E. coli at selected pHs or when coordinated with various metal ions and a significant effect on accelerating wound healing. The self-assembly approach presented in this work may serve as a generic strategy for the fabrication of novel multi-functional PEC hydrogels for broad biomedical applications.


Assuntos
Antibacterianos/química , Quitosana/química , Heparina/química , Polieletrólitos/química , Cicatrização/efeitos dos fármacos , Antibacterianos/farmacologia , Cátions , Escherichia coli/efeitos dos fármacos , Humanos , Hidrogéis , Concentração de Íons de Hidrogênio , Membranas Artificiais , Metais/química , Pele , Propriedades de Superfície , Resistência à Tração , Água
17.
Nat Chem Biol ; 15(10): 945-948, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31501590

RESUMO

Helical membrane proteins are typically assumed to attain stable transmembrane topologies immediately upon co-translational membrane insertion. Here we show that unassembled monomers of the small multidrug resistance (SMR) family exist in a dynamic equilibrium where the N-terminal transmembrane helix flips in and out of the membrane, with rates that depend on dimerization and the polypeptide sequence. Thus, membrane topology can display rapid dynamics in vivo and can be regulated by post-translational assembly.


Assuntos
Antiporters/metabolismo , Proteínas de Escherichia coli/química , Escherichia coli/fisiologia , Proteínas de Membrana/química , Sequência de Aminoácidos , Animais , Antibacterianos/farmacologia , Antiporters/genética , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Variação Genética , Proteínas de Membrana/metabolismo , Plasmídeos , Conformação Proteica
18.
Orv Hetil ; 160(36): 1437-1442, 2019 Sep.
Artigo em Húngaro | MEDLINE | ID: mdl-31492084

RESUMO

Introduction: Due to the inappropriate use of antibiotics (AB), more pathogens become multiresistant. One of the most severe sources of sepsis is cholangitis. To avoid fatal outcome, an effective AB policy plays a key role. Aim: To investigate the AB resistance of bacteria causing cholangitis and the efficacy of AB treatment. Patients and method: Microbiological tests of bile samples collected during cholangitis-indicated endoscopic retrograde cholangiopancreatographies were analysed at the First Department of Medicine, University of Szeged, in 2006 and in 2016. Results: 29 and 111 patients had bile sample collection in 2006 and in 2016, respectively. Of that, 22 (75%) and 106 (95%) were positive. Mean age: 61 ± 14 vs. 71 ± 14 years, no difference between men/women ratio. In 2006, 10 cases empirical AB (ciprofloxacine with metronidazole or imipenem) were used. In 9 cases (90%), the AB was adequate based on the microbiological results. In 2016, in 88 cases empirical AB was applied (ciprofloxacine and metronidazole, ceftriaxone with metronidazole or imipenem with metronidazole). In 29 cases, the empirical AB was ineffective. The efficacy of ciprofloxacine decreased to 64% in 2016. The profile of the most frequent cholangitis-causing pathogens (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae) was the same, but their resistency against ciprofloxacine increased. The rates of polymicrobal infections were 73% and 63%, respectively. Conclusion: The rates of positive bile samples were significantly higher in 2016. The profile of the most frequent pathogens was the same. The efficacy of the first-choice empirical AB ciprofloxacine decreased in 2016. The types of the most frequent cholangitis-causing bacteria are in line with the ones included in the Tokyo Guideline. Orv Hetil. 2019; 160(36): 1437-1442.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Bile/microbiologia , Colangite/tratamento farmacológico , Farmacorresistência Bacteriana , Idoso , Bactérias/classificação , Colangiopancreatografia Retrógrada Endoscópica , Colangite/microbiologia , Enterococcus faecalis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Feminino , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade
19.
J Agric Food Chem ; 67(40): 11066-11076, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508948

RESUMO

The electrospinning of nanofibers (NFs) of cinnamaldehyde inclusion complexes (ICs) with two different hydroxypropylated cyclodextrins (CDs), hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD), was successfully performed in order to produce cinnamaldehyde/CD-IC NFs without using an additional polymer matrix. The inclusion complexation between cinnamaldehyde and hydroxypropylated CDs was studied by computational molecular modeling, and the results suggested that HP-ß-CD and HP-γ-CD can be inclusion complexed with cinnamaldehyde at 1:1 and 2:1 (cinnamaldehyde/CD) molar ratios. Additionally, molecular modeling and phase solubility studies showed that water solubility of cinnamaldehyde dramatically increases with cyclodextrin inclusion complex (CD-IC) formation. The HP-ß-CD has shown slightly stronger binding with cinnamaldehyde when compared to HP-γ-CD for cinnamaldehyde/CD-IC. Although cinnamaldehyde is a highly volatile compound, it was effectively preserved with high loading by the cinnamaldehyde/CD-IC NFs. It was also observed that cinnamaldehyde has shown much higher temperature stability in cinnamaldehyde/CD-IC NFs compared to uncomplexed cinnamaldehyde because of the inclusion complexation state of cinnamaldehyde within the hydroxypropylated CD cavity. Moreover, cinnamaldehyde still has kept its antibacterial activity in cinnamaldehyde/CD-IC NF samples when tested against Escherichia coli. In addition, cinnamaldehyde/CD-IC NF mats were fast-dissolving in water, even though pure cinnamaldehyde has a water-insoluble nature. In brief, self-standing nanofibrous mats of electrospun cinnamaldehyde/CD-IC NFs are potentially applicable in food, oral-care, healthcare, and pharmaceutics because of their fast-dissolving character, enhanced water solubility, stability at elevated temperature, and promising antibacterial activity.


Assuntos
Acroleína/análogos & derivados , Antibacterianos/química , Antibacterianos/farmacologia , Composição de Medicamentos/métodos , Acroleína/química , Acroleína/farmacologia , Ciclodextrinas/química , Composição de Medicamentos/instrumentação , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Nanofibras/química , Solubilidade , Temperatura Ambiente
20.
BMC Infect Dis ; 19(1): 823, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31533647

RESUMO

BACKGROUND: The purpose of this study was to gather temporal trends on bacteria epidemiology and resistance of intraoperative bone culture from chronic ostemyelitis at an affiliated hospital in South China. METHOD: Records of patients with chronic osteomyelitis from 2003 to 2014 were retrospectively reviewed. The medical data were extracted using a unified protocol. Antimicrobial susceptibility testing was carried out by means of a unified protocol using the Kirby-Bauer method, results were analyzed according to Clinical and Laboratory Standards Institute definitions. RESULT: Four hundred eighteen cases met our inclusion criteria. For pathogen distribution, the top five strains were Staphylococcus aureus (27.9%); Pseudomonas aeruginosa (12.1%); Enterobacter cloacae (9.5%); Acinetobacter baumanii (9.0%) and Escherichia coli (7.8%). Bacterial culture positive rate was decreased significantly among different year-groups. Mutiple bacterial infection rate was 28.1%. One strain of Staphylococcus aureus was resistant to linezolid and vancomycin. Resistance of Pseudomonas aeruginosa stains to Cefazolin, Cefuroxime, Cefotaxime, and Cefoxitin were 100% nearly. Resistance of Acinetobacter baumanii stains against Cefazolin, Cefuroxime were 100%. Ciprofloxacin resistance among Escherichia coli isolates increased from 25 to 44.4%. On the contrary, resistance of Enterobacter cloacae stains to Cefotaxime and Ceftazidime were decreased from 83.3 to 36.4%. CONCLUSIONS: From 2003 to 2014, positive rate of intraoperative bone culture of chronic osteomyelitis was decreased; the proportion of Staphylococcus aureus was decreased gradually, and our results indicate the importance of bacterial surveilance studies about chronic osteomyelitis.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Osteomielite/diagnóstico , Adolescente , Adulto , Antibacterianos/uso terapêutico , Cefotaxima/farmacologia , Cefotaxima/uso terapêutico , China , Doença Crônica , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Feminino , Hospitais , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Osteomielite/tratamento farmacológico , Osteomielite/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Estudos Retrospectivos , Rifampina/farmacologia , Rifampina/uso terapêutico , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Adulto Jovem
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