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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.
Environ Technol ; 41(2): 211-221, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29969951

RESUMO

Glucose is one of the most abundant monosaccharides and the easiest carbon source to be consumed by bacteria. In this study, four culture media (LB, M9, M63 and MOPS) were supplemented with glucose at three different concentrations (4, 12.5 and 25 g/L) in the presence of a genetically modified strain of Escherichia coli with the purpose of selecting the most suitable culture medium to obtain ABD (acetoin (A) and 2,3-butanediol (2,3-BD)). The selected medium was M9, the cheapest culture medium, since the ABD yields obtained fermenting 12.5 and 25 g/L of glucose in M9 culture medium at 37°C, atmospheric pressure, initial pH 6.5, 100 rpm and 10% (v/v) of inoculum were similar compared to the ABD yields obtained using M63 and LB culture media. The influence of nitrogen on ABD yield was tested adding sodium nitrate (NaNO3) or urea ((NH2)2CO) to M9 culture medium at three different nitrogen concentrations (2.5, 5.0 and 7.0 g N/L). Adding urea (7.0 g N/L) to M9 supplemented with 25 g/L of glucose improved by 23% the ABD yield at 96 h compared to M9 without urea, reaching a value of 27.2% (g ABD/g glucose). In contrast, the use of NaNO3 had no significant effect on the ABD yield.


Assuntos
Escherichia coli , Glucose , Álcoois , Meios de Cultura , Fermentação , Nitrogênio
5.
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
6.
Bioresour Technol ; 296: 122367, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31727558

RESUMO

The aim of this work was to bioconvert all sugars in BSG into ethanol using a process scheme that includes the enzymatic hydrolysis of the whole slurry resulting from the pretreatment of BSG with phosphoric and sulfuric acid using previously optimised conditions, followed by the co-fermentation of the mixed sugars. More than 90% of the sugars in raw BSG were recovered in the pretreatment and the subsequent enzymatic hydrolysis of the whole slurry. The co-fermentation of the enzymatic hydrolysates with Escherichia coli was then compared with that the co-culture of Scheffersomyces stipitis and Saccharomyces cerevisiae, which resulted in lower ethanol production. The co-fermentation strategy with a single microorganism (E. coli) when BSG was pretreated with phosphoric acid resulted into the highest ethanol concentration, 39 g/L, which means that 222 L of ethanol can be obtained from a ton of BSG without detoxification requirements.


Assuntos
Escherichia coli , Etanol , Grão Comestível , Fermentação , Hidrólise
7.
Bioresour Technol ; 296: 122337, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31727559

RESUMO

The shortage of food based feedstocks is a challenge in industrial biomanufacturing. In this study, genetically modified Escherichia coli strains were used to produce isopropanol as the mainly product from acetate, a cost-effective nonfood-based substrate. The isopropanol biosynthesis pathway was constructed by combining genes from Clostridium acetobutylicum (thlA, adc), E. coli (atoDA) and Clostridium beijerinckii (adh). E. coli MG1655 harboring the isopropanol biosynthesis pathway successfully produced isopropanol and low amounts of acetone from pure acetate. The enhancement of the acetate assimilation pathway coupled with cofactor engineering strategy further improved the production of isopropanol to 18.5 mM with a yield of 0.26 mol/mol. With simple treatment, two kinds of biologically produced acetate were utilized to generate 16.7 and 24.5 mM isopropanol with yields of 0.25 and 0.56 mol/mol, respectively. Engineered E. coli with an optimized isopropanol biosynthesis pathway can efficiently utilize biologically produced acetate to synthesize isopropanol.


Assuntos
2-Propanol , Clostridium acetobutylicum , Acetatos , Escherichia coli , Fermentação , Engenharia Metabólica
8.
J Environ Manage ; 254: 109780, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31739092

RESUMO

Minimising the usage of potable water in industrial and cleaning processes is essential to conserve fresh water. Recycling treated wastewater will help to do so. However, high quality treated wastewater is required for reuse and recycling. This study evaluated the performance of an enhanced membrane bioreactor (eMBR) in treating car wash wastewater for the purpose of reuse. The eMBR consisted of an anaerobic tank, an anoxic tank, an aerobic membrane bioreactor (AMBR) and a UV disinfection unit. The effects of hydraulic retention time of the eMBR on the treated water quality parameters and operating parameters were evaluated. The eMBR produced high quality recyclable water (0.5-10.2 mg/L of COD, 0.18-0.83 NTU of turbidity, 0 org. of E. Coli/100 mL) meeting Class A recycle water standards. Decrease in the mixed liquor suspended solids concentration in the AMBR (from 294 to 117 mg/L) reduced the fouling of the membrane which increased the permeate flux (from 5.9 to 6.7 L/m2h). This is unique to the eMBR system used in this study. However, when the flux exceeded the critical flux, the trans-membrane pressure increased significantly.


Assuntos
Águas Residuárias , Purificação da Água , Reatores Biológicos , Escherichia coli , Membranas Artificiais , Eliminação de Resíduos Líquidos
9.
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
10.
Food Microbiol ; 85: 103283, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500718

RESUMO

Many countries use Escherichia coli and coliforms as indicators of sanitary quality of foods and have set limits for cheeses, including raw-milk cheeses. This paper reviewed the scientific literature for E. coli and coliform levels that are found in different types of raw milk, the fate of indicators during the manufacturing and ripening of different cheeses and the indicator levels that have been found in the finished cheeses. These studies from worldwide showed that E. coli and coliforms are found in different types of raw milk but usually at <100 CFU/ml or not found. Instances where raw milk contained indicator levels >1000 CFU/ml have mostly been attributed to unsanitary conditions/production. During cheese-making, indicators present in raw milk will often increase in numbers, but the levels decline as the acidity from lactose fermentation decreases the pH. Except for fresh cheeses that are not aged, indicator levels are further reduced by 2-3 log10 CFU/g or more, during the ripening process. As a result, indicator levels in finished cheeses are often low and within the limits of <10 or <100 CFU/g set by many countries. The cited studies also show that raw milk cheeses that are made with quality raw milk, under hygienic conditions and properly aged, should not contain high levels of indicator bacteria in the final product.


Assuntos
Bactérias/crescimento & desenvolvimento , Queijo/microbiologia , Microbiologia de Alimentos/métodos , Microbiologia de Alimentos/normas , Alimentos Crus/microbiologia , Animais , Queijo/normas , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Escherichia coli/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Manipulação de Alimentos , Leite/microbiologia
11.
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
12.
Food Chem ; 308: 125646, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31654977

RESUMO

Hydroxytyrosol (HT), which is a polyphenol with a high antioxidant power and many associated health benefits, has been found in wines. Wine yeasts are capable of producing high amounts of the higher alcohol tyrosol, which is the precursor for HT synthesis. We have improved the ability of Saccharomyces cerevisiae to produce HT by heterologously expressing the HpaBC enzyme complex of Escherichia coli, which hydroxylates tyrosol into HT. By overexpressing the hpaB and hpaC genes, we achieved HT titers of 1.15 ±â€¯0.05 mg/L and 4.6 ±â€¯0.9 mg/L in a minimal medium in which either 1 mM tyrosine or 1 mM tyrosol were respectively added. This work demonstrates that the overexpression of HpaBC in yeast is a promising tool to overproduce HT at the expense of endogenous tyrosol through central carbon catabolism flux redirection to tyrosine catabolism.


Assuntos
Escherichia coli/metabolismo , Oxigenases de Função Mista/metabolismo , Álcool Feniletílico/análogos & derivados , Saccharomyces cerevisiae/metabolismo , Escherichia coli/genética , Oxigenases de Função Mista/genética , Álcool Feniletílico/metabolismo , Saccharomyces cerevisiae/genética
13.
APMIS ; 128(1): 10-19, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642122

RESUMO

Atherogenesis is associated with chronic gut infections; however, the mechanisms are not clear. The aim of the study was to determine whether lipopolysaccharide of E. coli (E. coli LPS) may affect endothelial barrier and modify IL-10 expression in dendritic cells (DCs). Human umbilical vein endothelial cells (HUVECs) and monocyte-derived DCs were treated with E. coli LPS, apolipoprotein B100 (ApoB100) and 7-ketocholesterol (7-kCH) - harmful oxidized form of cholesterol. The effect of E. coli LPS, 7-kCH and ApoB100 on the barrier functions of HUVECs in real-time cell electric impedance sensing system (RTCA-DP) was assessed. Furthermore, the effect of 7-kCH and ApoB100 on barrier functions of HUVECs co-cultured with DCs previously treated with LPS was analyzed. Both E. coli LPS and 7-kCH decreased barrier functions of HUVECs and reduced tight junction protein mRNA expression, whereas ApoB100 increased endothelial barrier. In DCs, ApoB100 and E. coli LPS decreased IL-10 mRNA expression. In HUVECs co-cultured with DCs treated with LPS and subsequently pulsed with ApoB100 or 7-kCH, IL-10 mRNA expression was lower. E. coli LPS-exposed DCs diminished the protective effect of ApoB100 on endothelial integrity and led to the decrease in occludin mRNA expression. LPS potentially derived from gut microflora may destabilize endothelial barrier together with oxidized cholesterol and intensify the immunogenicity of ApoB100.


Assuntos
Células Dendríticas/efeitos dos fármacos , Escherichia coli/imunologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Interleucina-10/genética , Lipopolissacarídeos/imunologia , Junções Íntimas/efeitos dos fármacos , Apolipoproteína B-100/farmacologia , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/imunologia , Escherichia coli/química , Humanos , Cetocolesteróis/farmacologia , Lipopolissacarídeos/farmacologia , Ocludina/genética , Transdução de Sinais/efeitos dos fármacos , Proteínas de Junções Íntimas/genética
14.
J Water Health ; 17(6): 921-929, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31850899

RESUMO

Solar water disinfection (SODIS) is a process by which microbially contaminated water is disinfected by transmitting solar ultraviolet radiation to the water, rendering the bacteria inactive. The purpose of this project was to determine a residence time for disinfection in specific applications using a 3-log reduction in colony-forming units per milliliter (CFU/mL). The water was contained in quartz tubes and tested over both flat and parabolic reflectors. While UVA and UVB radiation are diffuse and independent of reflector style, water temperature is affected by solar concentration. The two reflector styles were studied to identify how insolation level and temperature affects the bacteria inactivation process. Escherichia coli, DH5α, was inoculated into sterile water and treated for 2, 4, and 8 h. The study had several conclusions, first that a 5-log reduction was achieved after 2 h, for all water temperature and insolation levels. The reflector style did not have a measurable effect on inactivation due to the short disinfection time, but the water temperature increased significantly with the parabolic reflectors. A thermal model of the two systems confirmed that the parabolic configuration resulted in higher energy input, making it the preferred configuration for disinfection with lower residence times.


Assuntos
Desinfecção/métodos , Escherichia coli/efeitos da radiação , Raios Ultravioleta , Purificação da Água/métodos , Relação Dose-Resposta à Radiação , Humanos , Luz Solar , Temperatura Ambiente , Água/química , Microbiologia da Água
15.
Yi Chuan ; 41(12): 1138-1147, 2019 Dec 20.
Artigo em Chinês | MEDLINE | ID: mdl-31857285

RESUMO

Pathogenic Escherichia coli (E. coli) is the most common pathogen causing urinary tract infection in animals. We investigated the antibiotic resistance and virulence genes of pathogenic E. coli CCHTP derived from urine with occult blood of the giant panda by whole genome sequencing. The flanking sequencing of resistance and virulence genes in genomic islands were also analyzed. Our results demonstrate that E. coli CCHTP contains different families of antibiotic resistance genes, most of which are efflux pump related genes, including multiple drug resistance efflux pump genes mdfA, emrE, and mdtN. A total of 166 virulence factors and 563 virulence genes were identified, and the most virulence factors and related genes are involved in host cell attachment and invasion processes. Furthermore, sequence analysis of 19 genomic islands revealed that antibiotic and virulence genes are associated with mobile genetic elements (transposon and insertion sequence) in GIs011 and GIs017. These structures can mediate horizontal transfer of antibiotic and virulence genes. Our work described the distribution of antibiotic resistance genes and virulence genes in E. coli CCHTP, which may provide an important guidance for treatment and rational drug use of E. coli CCHTP infection in the giant panda.


Assuntos
Farmacorresistência Bacteriana , Proteínas de Escherichia coli , Escherichia coli , Urina , Ursidae , Animais , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Genoma Bacteriano , Urina/microbiologia , Ursidae/microbiologia , Virulência/genética , Fatores de Virulência/genética , Sequenciamento Completo do Genoma
16.
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
17.
Zhongguo Zhong Yao Za Zhi ; 44(22): 4864-4873, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31872594

RESUMO

Fifteen limonoids were isolated from 95% ethanol extracts of the dry seeds of neem( Azadirachta indica) by various column chromatography techniques including silica gel,Pharmadex LH-20 gel and ODS resin. Based on spectroscopic analysis,their structures were determined as nimbocinol( 1),17ß-hydroxynimbocinol( 2),1α,3α,7α-triacetylvilasinin( 3),7α-benzoyltrichilinin( 4),1,3-diacetyl-7-tigloyl-12-hydroxyvilasinin( 5),3-deacetylsalannin( 6),1-O-acetyl-1-detigloylsalannin( 7),2'( R),3'-dihydrosalannin( 8),2'( S),3'-dihydrosalannin( 9),2,3-dihydronimbolide( 10),6-homodesacetylnimbin( 11),gedunin( 12),7-deacetyl-7-epi-dihydrogedunin( 13),7-deacetoxy-7α-hydroxygedunin( 14) and nimbinene( 15). Compound 7 is a new natural product. 4,8,9,13 and 14 are isolated from the genus Azadirachta for the first time. Compound 2 showed inhibitory activity against Escherichia coli and Staphylococcus epidermidis,with MIC values of 32 and 128 mg·L~(-1),respectively. Compound 10 showed moderate inhibitory activity against S. epidermidis with a MIC value of 64 mg·L~(-1). Compound 11 inhibited the growth of E. coli and Pseudomonas aeruginosa,both with MIC values of 128 mg·L~(-1). Compound 15 exhibited inhibitory activity against P. aeruginosa,with a MIC value of128 mg·L~(-1).


Assuntos
Antibacterianos/farmacologia , Azadirachta , Limoninas , Extratos Vegetais/farmacologia , Escherichia coli , Sementes
18.
Pol J Microbiol ; 68(4): 559-563, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880899

RESUMO

We demonstrate here for the first time the use of an IncP-1ß plasmid, R751, as a gene capture vehicle for recombineering/conjugation strategies to clone large segments of bacterial genomes (20 - 100 + Kb). We designed R751 derivatives containing alternative markers for greater flexibility when using the R751 vehicle across different bacteria. These markers are removable if desired as part of the cloning procedure (with no extra steps needed). We demonstrated utility via cloning of 38 and 22 kb genomic segments from Salmonella enterica serovar Typhimurium and Escherichia coli, respectively. The plasmids expand the options available for use in recombineering/conjugation-based cloning applications.We demonstrate here for the first time the use of an IncP-1ß plasmid, R751, as a gene capture vehicle for recombineering/conjugation strategies to clone large segments of bacterial genomes (20 ­ 100 + Kb). We designed R751 derivatives containing alternative markers for greater flexibility when using the R751 vehicle across different bacteria. These markers are removable if desired as part of the cloning procedure (with no extra steps needed). We demonstrated utility via cloning of 38 and 22 kb genomic segments from Salmonella enterica serovar Typhimurium and Escherichia coli, respectively. The plasmids expand the options available for use in recombineering/conjugation-based cloning applications.


Assuntos
Clonagem Molecular , Conjugação Genética , Escherichia coli/genética , Plasmídeos/genética , Salmonella typhimurium/genética , DNA Bacteriano/genética , Recombinação Genética
19.
Georgian Med News ; (294): 132-136, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31687965

RESUMO

The work is dedicated to the study of biofilms formation process by main pyelonephritis causative agents in children in vitro using methods of light, fluorescent and scanning microscopy. To study biofilms formation bacteria were cultivated in liquid substratum on glass in polystyrene Petri dishes d=40mm. The study demonstrated that all isolates formed biofilms. Adhesion of bacteria planktonic forms took place on the first stage, intracellular matrix formation took place on the second stage, and biofilms formation took place on the third stage. During the study of E. coli and Proteus sрр bacteria preparations with the use of scanning and light microscopy ordered bacteria arrangement was seen in the form of separate structures or tiny clusters of bacterial cells united by matrix. During the study of the ability to form P. aeruginosa isolates biofilms with the help of scanning microscopy it was stated that the adhesion of separate bacterial cells occurs by conglomerates formation surrounded by matrix with further biofilms formation. Bacterial cells in the form of dense elongated sticks were seen under the film. P. аeruginosa isolates daily biofilms were stated to have dense structure in the form of gel. Packed biofilms areas with cells clusters with good fluorescence were found with the help of fluorescent microscopy. During daily K.рneumoniae isolates biofilms study by methods of scanning and fluorescent microscopy it was found that K.рneumoniae biofilms were covered with dense matrix and riddled with multiple canals in the form of apertures. During morphological peculiarities study of E. faecalis isolates biofilms formation with the use of scanning and fluorescent microscopy it was found that bacterial cells were densely packed and united by intracellular matrix under which bacteria of spherical shape were seen. Thus biofilms, the nature of which depends on the type of bacteria, are formed on the surface of conglomerates consisting of bacterial cells. Peculiarities of course and appearance of pyelonephritis chronic form and relapses in children is explained by biofilms formation.


Assuntos
Biofilmes/crescimento & desenvolvimento , Escherichia coli/fisiologia , Pseudomonas aeruginosa/fisiologia , Pielonefrite/microbiologia , Bactérias , Criança , Humanos , Pielonefrite/complicações , Pielonefrite/patologia , Pielonefrite/urina
20.
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
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