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1.
Sci Rep ; 11(1): 18444, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34531449

RESUMO

Over the past year, the world's attention has focused on combating COVID-19 disease, but the other threat waiting at the door-antimicrobial resistance should not be forgotten. Although making the diagnosis rapidly and accurately is crucial in preventing antibiotic resistance development, bacterial identification techniques include some challenging processes. To address this challenge, we proposed a deep neural network (DNN) that can discriminate antibiotic-resistant bacteria using surface-enhanced Raman spectroscopy (SERS). Stacked autoencoder (SAE)-based DNN was used for the rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) bacteria using a label-free SERS technique. The performance of the DNN was compared with traditional classifiers. Since the SERS technique provides high signal-to-noise ratio (SNR) data, some subtle differences were found between MRSA and MSSA in relative band intensities. SAE-based DNN can learn features from raw data and classify them with an accuracy of 97.66%. Moreover, the model discriminates bacteria with an area under curve (AUC) of 0.99. Compared to traditional classifiers, SAE-based DNN was found superior in accuracy and AUC values. The obtained results are also supported by statistical analysis. These results demonstrate that deep learning has great potential to characterize and detect antibiotic-resistant bacteria by using SERS spectral data.


Assuntos
Resistência a Meticilina , Staphylococcus aureus/classificação , Staphylococcus aureus/crescimento & desenvolvimento , Aprendizado Profundo , Análise Discriminante , Humanos , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Redes Neurais de Computação , Razão Sinal-Ruído , Prata/química , Análise Espectral Raman , Staphylococcus aureus/efeitos dos fármacos , Máquina de Vetores de Suporte
2.
J Med Microbiol ; 70(9)2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34553684

RESUMO

The pH of skin is critical for skin health and resilience and plays a key role in controlling the skin microbiome. It has been well reported that under dysbiotic conditions such as atopic dermatitis (AD), eczema, etc. there are significant aberrations of skin pH, along with a higher level of Staphylococcus aureus compared to the commensal Staphylococcus epidermidis on skin. To understand the effect of pH on the relative growth of S. epidermidis and S. aureus, we carried out simple in vitro growth kinetic studies of the individual microbes under varying pH conditions. We demonstrated that the growth kinetics of S. epidermidis is relatively insensitive to pH within the range of 5-7, while S. aureus shows a stronger pH dependence in that range. Gompertz's model was used to fit the pH dependence of the growth kinetics of the two bacteria and showed that the equilibrium bacterial count of S. aureus was the more sensitive parameter. The switch in growth rate happens at a pH of 6.5-7. Our studies are in line with the general hypothesis that keeping the skin pH within an acidic range is advantageous in terms of keeping the skin microbiome in balance and maintaining healthy skin.


Assuntos
Meios de Cultura/química , Pele/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento , Humanos , Concentração de Íons de Hidrogênio
3.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360764

RESUMO

This paper presents the results of structure-activity relationship (SAR) studies of 140 3,3'-(α,ω-dioxaalkan)bis(1-alkylimidazolium) chlorides. In the SAR analysis, the dominance-based rough set approach (DRSA) was used. For analyzed compounds, minimum inhibitory concentration (MIC) against strains of Staphylococcus aureus and Pseudomonas aeruginosa was determined. In order to perform the SAR analysis, a tabular information system was formed, in which tested compounds were described by means of condition attributes, characterizing the structure (substructure parameters and molecular descriptors) and their surface properties, and a decision attribute, classifying compounds with respect to values of MIC. DRSA allows to induce decision rules from data describing the compounds in terms of condition and decision attributes, and to rank condition attributes with respect to relevance using a Bayesian confirmation measure. Decision rules present the most important relationships between structure and surface properties of the compounds on one hand, and their antibacterial activity on the other hand. They also indicate directions of synthesizing more efficient antibacterial compounds. Moreover, the analysis showed differences in the application of various parameters for Gram-positive and Gram-negative strains, respectively.


Assuntos
Antibacterianos , Imidazóis , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Relação Estrutura-Atividade
4.
Nutrients ; 13(7)2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34371869

RESUMO

Hibiscus sabdariffa L. (H.s.) is a polyphenolic-rich plant commonly consumed either as a beverage or spice. The aim of the present study was to evaluate the in vitro digestibility of H.s. polyphenols using an in vitro model of digestion which simulates the human stomach and small intestine. The bioaccessible polyphenols released in the digested samples were analyzed by liquid chromatography coupled to photodiode array and mass spectrometry detection. H.s. anthocyanins (cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside) content drastically dropped during the digestion process from 2.91 ± 0.03 µg g-1 and 8.53 ± 0.08 µg g-1 (w/w) CG (Cyanidin-glucoside) in the raw extract, respectively, to 0.12 ± 0.01 µg g-1 0.12 ± 0.01 µg g-1 (w/w) CG at the end of duodenal digestion. Total polyphenols also have shown a decrease from 1192.65 ± 30.37 µg g-1 (w/w) in the raw extract to 282.24 ± 7.21 µg g-1 (w/w) by the end of gastric digestion, in contrast to their increase by the end of duodenal digestion 372.91 ± 3.97 µg g-1 (w/w). On the other hand, the decrease in certain compounds (e.g., caffeoylquinicandcoumaroylquinic acids) was observed during gastric digestion resulting in an increase of quinic acid in the duodenal aliquots, thus suggesting that this compound was derived from the degradation of the more complex hydroxycinnamic acids. H.s. extract also exhibited a bacteriostatic effect against Staphylococcus aureus ATCC 6538 (MIC of 2.5 mg mL-1) and a bactericidal effect against a food isolate of Listeria monocytogenes (MBC of 2.5 mg mL-1). The undigested polyphenols of H.s. in the upper gastrointestinal tract enters the colon, where they are metabolized by the gut microbiota. The present study results showed that resistance of H.s. polyphenols during gastrointestinal digestion might affect their uptake, resulting in a decrease in their digestibility.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Digestão , Hibiscus , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Bactérias/crescimento & desenvolvimento , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Suco Gástrico/química , Hibiscus/química , Humanos , Secreções Intestinais/química , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Polifenóis/isolamento & purificação , Polifenóis/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Espectrometria de Massas em Tandem
5.
Molecules ; 26(16)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34443349

RESUMO

Ulva sp. is known to be a source of bioactive compounds such as ulvans, but to date, their biological activity on skin commensal and/or opportunistic pathogen bacteria has not been reported. In this study, the effects of poly- and oligosaccharide fractions produced by enzyme-assisted extraction and depolymerization were investigated, for the first time in vitro, on cutaneous bacteria: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes. At 1000 µg/mL, poly- and oligosaccharide fractions did not affect the growth of the bacteria regarding their generation time. Polysaccharide Ulva sp. fractions at 1000 µg/mL did not alter the bacterial biofilm formation, while oligosaccharide fractions modified S. epidermidis and C. acnes biofilm structures. None of the fractions at 1000 µg/mL significantly modified the cytotoxic potential of S. epidermidis and S. aureus towards keratinocytes. However, poly- and oligosaccharide fractions at 1000 µg/mL induced a decrease in the inflammatory potential of both acneic and non-acneic C. acnes strains on keratinocytes of up to 39.8%; the strongest and most significant effect occurred when the bacteria were grown in the presence of polysaccharide fractions. Our research shows that poly- and oligosaccharide Ulva sp. fractions present notable biological activities on cutaneous bacteria, especially towards C. acnes acneic and non-acneic strains, which supports their potential use for dermo-cosmetic applications.


Assuntos
Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Microbiota/efeitos dos fármacos , Extratos Vegetais/farmacologia , Pele/microbiologia , Ulva/química , Bactérias/patogenicidade , Relação Dose-Resposta a Droga , Propionibacteriaceae/efeitos dos fármacos , Propionibacteriaceae/crescimento & desenvolvimento , Propionibacteriaceae/patogenicidade , Propionibacteriaceae/fisiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/patogenicidade , Staphylococcus aureus/fisiologia , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus epidermidis/patogenicidade , Staphylococcus epidermidis/fisiologia , Virulência/efeitos dos fármacos
6.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361741

RESUMO

Due to their richness of bioactive substances, rose hips are a valuable raw material for obtaining extracts with potential antimicrobial activity. The aim of the study was to determine the antagonistic potential of whole pseudo-fruit and flesh extracts of three Rosa sp. varieties against Staphylococcus spp. bacteria isolated as food contaminants. The biological material in this study consisted of seven strains of bacteria from the genus Staphylococcus. Two strains-Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis DSMZ 3270-were used as reference strains. The other five strains were food-derived isolates-S. epidermidis A5, S. xylosus M5, S. haemolyticus M6, S. capitis KR6, and S. warneri KR2A. The material was the pseudo-fruits of Rosa canina, Rosa pomifera Karpatia, and Rosa rugosa. The polyphenols were extracted from the fleshy part and the whole pseudo-fruit for all rose varieties. The tested preparations differed significantly in their polyphenol composition. The sum of polyphenols ranged from 28 862 to 35 358 mg/100 g of lyophilisate. The main groups of polyphenols found in the preparations were flavanols and ellagitannins. All of the tested extracts inhibited the growth of staphylococci at a concentration of 500 mg/mL. Rosa rugosa fruit extract showed the strongest antimicrobial properties among the studied extracts. For all the strains, the growth inhibition had a diameter of 20.3-29.0 mm. Moreover, six out of the seven tested strains showed the highest inhibition with the use of this extract. The MIC of rose extracts was in the range of 3.125-500 mg/mL and was strictly dependent on the bacterial species, the species of the rose, and the part of the fruit from which the extract was obtained. Correlations were assessed between the main groups of polyphenols in the extracts and their inhibition of bacterial growth. In the case of pseudo-fruit extracts, the inhibitory effect on bacterial growth positively correlated with the content of ellagitannins, and this effect was observed for almost all the tested strains. The results presented herein follow the current trend of minimising the use of chemical preservatives in food; from this point of view, rose extracts are very promising.


Assuntos
Antibacterianos/química , Flavonoides/química , Taninos Hidrolisáveis/química , Polifenóis/química , Rosa/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos/métodos , Frutas/química , Humanos , Taninos Hidrolisáveis/isolamento & purificação , Taninos Hidrolisáveis/farmacologia , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Polifenóis/isolamento & purificação , Polifenóis/farmacologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus capitis/efeitos dos fármacos , Staphylococcus capitis/crescimento & desenvolvimento , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/crescimento & desenvolvimento
7.
Molecules ; 26(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34361717

RESUMO

The development of bio-based nanocomposites is of high scientific and industrial interest, since they offer excellent advantages in creating functional materials. However, dispersion and distribution of the nanomaterials inside the polymer matrix is a key challenge to achieve high-performance functional nanocomposites. In this context, for better dispersion, biobased triethyl citrate (TEC) as a dispersing agent in a liquid-assisted extrusion process was used to prepare the nanocomposites of poly (lactic acid) (PLA) and chitin nanocrystals (ChNCs). The aim was to identify the effect of the TEC content on the dispersion of ChNCs in the PLA matrix and the manufacturing of a functional nanocomposite. The nanocomposite film's optical properties; microstructure; migration of the additive and nanocomposites' thermal, mechanical and rheological properties, all influenced by the ChNC dispersion, were studied. The microscopy study confirmed that the dispersion of the ChNCs was improved with the increasing TEC content, and the best dispersion was found in the nanocomposite prepared with 15 wt% TEC. Additionally, the nanocomposite with the highest TEC content (15 wt%) resembled the mechanical properties of commonly used polymers like polyethylene and polypropylene. The addition of ChNCs in PLA-TEC15 enhanced the melt viscosity, as well as melt strength, of the polymer and demonstrated antibacterial activity.


Assuntos
Antibacterianos/síntese química , Quitina/química , Citratos/química , Nanocompostos/química , Nanopartículas/química , Poliésteres/química , Antibacterianos/farmacologia , Módulo de Elasticidade , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Reologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração , Viscosidade
8.
Methods Mol Biol ; 2341: 1-7, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264454

RESUMO

Many S. aureus strains produce membrane-associated carotenoid pigments, advantageous secondary metabolites that can alter membrane fluidity, resistance to antimicrobial peptides (AMPs) and act as antioxidants, properties that can impact resistance against aspects of the host innate immune system. Several studies have reported connections between mutations in both regulatory (i.e., alternative sigma factor B) and metabolic (purine biosynthesis, oxidative phosphorylation) genes, and noticeable differences in carotenoid pigmentation. This chapter outlines a simple protocol to quantify cellular pigments using a methanol extraction method.


Assuntos
Carotenoides/isolamento & purificação , Metanol/química , Staphylococcus aureus/crescimento & desenvolvimento , Carotenoides/química , Fracionamento Químico , Regulação Bacteriana da Expressão Gênica , Fluidez de Membrana , Espectrofotometria , Staphylococcus aureus/metabolismo
9.
Methods Mol Biol ; 2341: 9-16, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264455

RESUMO

Zymography has been used to analyze enzymatic activity and processing of enzymes for many years. We have used bacterial cells copolymerized into the acrylamide gel to analyze specific activity of murein hydrolases of interest. In addition, this method has been widely used to examine and distinguish protease activities using different substrates. This chapter provides instruction for zymography of both extracellular murein hydrolases and proteases produced by Staphylococcus aureus.


Assuntos
N-Acetil-Muramil-L-Alanina Amidase/análise , Peptídeo Hidrolases/análise , Staphylococcus aureus/crescimento & desenvolvimento , Proteínas de Bactérias/análise , Proteínas de Bactérias/metabolismo , Eletroforese em Gel de Poliacrilamida/métodos , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Peptídeo Hidrolases/metabolismo , Staphylococcus aureus/enzimologia
10.
Methods Mol Biol ; 2341: 25-30, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264457

RESUMO

Many strains of Staphylococcus aureus produce a variety of cytolysins that target many different cell types to both fight the immune system and acquire nutrients. This includes hemolysins which destroy erythrocytes and are well studied virulence factors. Traditionally, hemolysin activity is measured on blood agar plates due to the simplicity of the assay. While this is telling, it cannot encapsulate the full story because S. aureus is known to behave differently in broth and on agar. Furthermore, plate-based assays are primarily semiquantitative and often a more accurate determination of hemolytic potential is needed to discern differences between strains. Here, we describe a method to quantify hemolysin activity from broth or similarly grown cells.


Assuntos
Eritrócitos/fisiologia , Proteínas Hemolisinas/análise , Staphylococcus aureus/crescimento & desenvolvimento , Animais , Proteínas de Bactérias/análise , Proteínas de Bactérias/metabolismo , Meios de Cultura/química , Proteínas Hemolisinas/metabolismo , Hemólise , Humanos , Staphylococcus aureus/metabolismo , Staphylococcus aureus/patogenicidade , Fatores de Virulência/análise , Fatores de Virulência/metabolismo
11.
Methods Mol Biol ; 2341: 45-54, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264460

RESUMO

This chapter describes the use of antibiotic kill curves to examine the tolerance of Staphylococcus aureus to any antibiotic of interest. This is done by treating cultures with a super-minimum inhibitory concentration (MIC) of antibiotic and measuring viability over time by colony-forming units (CFUs). Kill curves provide a unique insight into S. aureus antibiotic tolerance and death patterns that may not be clear from other experiments, such as traditional MIC or Kirby-Bauer assays.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Staphylococcus aureus/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
12.
Methods Mol Biol ; 2341: 55-68, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264461

RESUMO

Fluorescence polarization is a method to determine membrane fluidity using a hydrophobic fluorescent dye that intercalates into the fatty acid bilayer. A spectrofluorometer is used to polarize UV light as a vertical excitation beam which passes through the dye-labeled membrane where the dye fluoresces. The beams perpendicular and horizontal to the excitation light are then collected and analyzed. Membrane structural properties are largely due to the packing of the fatty acids in the lipid bilayer that determines the membrane biophysical parameters. Staphylococcus aureus contains straight-chain (SCFAs) and branched-chain (BCFAs) fatty acids in the membrane and alters the proportion of membrane fluidizing BCFAs and stabilizing SCFAs as a response to a variety of stresses. Herein, we describe a method for determination of membrane fluidity in S. aureus using diphenylhexatriene, one of the most used fluorescent dyes for this purpose.


Assuntos
Difenilexatrieno/química , Ácidos Graxos/análise , Corantes Fluorescentes/química , Staphylococcus aureus/crescimento & desenvolvimento , Membrana Externa Bacteriana/química , Ácidos Graxos/química , Polarização de Fluorescência , Bicamadas Lipídicas/química , Fluidez de Membrana , Espectrometria de Fluorescência , Staphylococcus aureus/química
13.
Methods Mol Biol ; 2341: 79-88, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264463

RESUMO

The Rotary Cell Culture System (RCCS) is an apparatus that was originally designed by NASA engineers to simulate microgravity conditions for growth of both eukaryotic and bacterial cell cultures. The RCCS growth environment is also characterized by low fluid shear stress, thereby also providing an in vitro growth condition relevant to certain in vivo environments encountered during bacterial infection. This chapter describes a method for growing Staphylococcus aureus under simulated microgravity conditions using the RCCS and disposable High Aspect Ratio Vessels (HARVs). Small samples can be removed and replaced with fresh media during the experiment (continuous sampling method) or the whole culture can be removed at the end of the experiment (end-point sampling method) for larger sample volumes required for follow-up studies such as RNAseq or proteomics.


Assuntos
Técnicas Bacteriológicas/métodos , Staphylococcus aureus/crescimento & desenvolvimento , Simulação de Ausência de Peso/instrumentação , Técnicas Bacteriológicas/instrumentação , Perfilação da Expressão Gênica , Proteômica , Análise de Sequência de RNA , Resistência ao Cisalhamento
14.
Methods Mol Biol ; 2341: 89-94, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264464

RESUMO

Oxygen consumption is a fundamental characteristic of staphylococcal physiology reflecting the energy and metabolic state of the bacterial cell. During aerobic growth, oxygen consumption rates (OCR) depend on nutrient availability and vary at different growth stages. The measurement of oxygen consumption rates provides a versatile tool to characterize the impact of various mutations, environmental cues, and antibiotics on bacterial growth and fitness. In this chapter, we describe a MitoXpress® Xtra-based oxygen consumption assay for fast and reliable determination of respiration rates in Staphylococcus aureus. This highly reproducible and simple method requires a minimal set of reagents and allows rapid screening of multiple samples through real-time determination of the OCR with an oxygen-sensing probe and fluorescence plate reader.


Assuntos
Antibacterianos/farmacologia , Oxigênio/análise , Staphylococcus aureus/crescimento & desenvolvimento , Técnicas Biossensoriais , Fluorimunoensaio , Aptidão Genética , Mutação , Consumo de Oxigênio , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
15.
Methods Mol Biol ; 2341: 103-116, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264466

RESUMO

Developments in mass spectrometry have made it possible to identify individual biomolecules in complex samples. This has led to advances in the detection and quantification of both extracellular and intracellular metabolites, such as amino acids, organic acids, fatty acids, nucleotides, and CoA-esters from growth media and cellular extracts. However, the reproducibility of metabolite data can be problematic if the concentrations and/or stability of metabolites fluctuate during culture harvesting and processing. Herein we describe a standardized and efficient collection protocol and best practices for preservation and harvesting of Staphylococcus aureus cellular and supernatant samples to improve reproducibility, reliability, and consistency in mass-spectrometry-based metabolite data sets.


Assuntos
Metabolômica/métodos , Staphylococcus aureus/crescimento & desenvolvimento , Aerobiose , Guias como Assunto , Espectrometria de Massas , Staphylococcus aureus/metabolismo
16.
Methods Mol Biol ; 2341: 127-131, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264468

RESUMO

Staphylococcus aureus is an important human pathogen that causes a plethora of diverse infections within the human host that range in severity from the relatively minor to the severe. Of note, bloodstream infections caused by this organism result in high mortality rates, often following failed rounds of surgical and antibiotic intervention. The capacity for S. aureus to exist in blood is driven by myriad virulence factors that engage in a manipulation of various host responses to evade destruction and ensure survival. These include both secreted elements, such as coagulase and von Willebrand factor protein, as well as surface displayed factors, including clumping factor A and fibronectin binding protein A. In addition to this, there are a number of other loci within the S. aureus genome whose products have been shown to contribute to blood survival by more indirect means. Accordingly, ex vivo whole human blood survival assays are often used as a preliminary study to investigate host-bacterial interactions in an effort to delineate the pathogenicity of S. aureus strains. Herein we provide a detailed assessment of the protocol required to perform such studies.


Assuntos
Sangue/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Fatores de Virulência/metabolismo , Proteínas de Bactérias/metabolismo , Sangue/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Viabilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo , Staphylococcus aureus/patogenicidade
17.
Molecules ; 26(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206375

RESUMO

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs-ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis's spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).


Assuntos
Antibacterianos , Carvão Vegetal , Escherichia coli/crescimento & desenvolvimento , Química Verde , Nanopartículas Metálicas/química , Prata , Staphylococcus aureus/crescimento & desenvolvimento , Têxteis , Aloe/química , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Carvão Vegetal/química , Carvão Vegetal/farmacologia , Extratos Vegetais/química , Prata/química , Prata/farmacologia
18.
Molecules ; 26(12)2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198596

RESUMO

Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacteria represent major infectious threats in the hospital environment due to their wide distribution, opportunistic behavior, and increasing antibiotic resistance. This study reports on the deposition of polyvinylpyrrolidone/antibiotic/isoflavonoid thin films by the matrix-assisted pulsed laser evaporation (MAPLE) method as anti-adhesion barrier coatings, on biomedical surfaces for improved resistance to microbial colonization. The thin films were characterized by Fourier transform infrared spectroscopy, infrared microscopy, and scanning electron microscopy. In vitro biological assay tests were performed to evaluate the influence of the thin films on the development of biofilms formed by Gram-positive and Gram-negative bacterial strains. In vitro biocompatibility tests were assessed on human endothelial cells examined for up to five days of incubation, via qualitative and quantitative methods. The results of this study revealed that the laser-fabricated coatings are biocompatible and resistant to microbial colonization and biofilm formation, making them successful candidates for biomedical devices and contact surfaces that would otherwise be amenable to contact transmission.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Flavonoides/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Biofilmes/crescimento & desenvolvimento , Materiais Revestidos Biocompatíveis/química , Flavonoides/química , Lasers/normas , Testes de Sensibilidade Microbiana/métodos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Propriedades de Superfície
19.
Int J Mol Sci ; 22(12)2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34201173

RESUMO

Biofilms are the reason for a vast majority of chronic inflammation cases and most acute inflammation. The treatment of biofilms still is a complicated task due to the low efficiency of drug delivery and high resistivity of the involved bacteria to harmful factors. Here we describe a magnetically controlled nanocomposite with a stimuli-responsive release profile based on calcium carbonate and magnetite with an encapsulated antibiotic (ciprofloxacin) that can be used to solve this problem. The material magnetic properties allowed targeted delivery, accumulation, and penetration of the composite in the biofilm, as well as the rapid triggered release of the entrapped antibiotic. Under the influence of an RF magnetic field with a frequency of 210 kHz, the composite underwent a phase transition from vaterite into calcite and promoted the release of ciprofloxacin. The effectiveness of the composite was tested against formed biofilms of E. coli and S. aureus and showed a 71% reduction in E. coli biofilm biomass and an 85% reduction in S. aureus biofilms. The efficiency of the composite with entrapped ciprofloxacin was higher than for the free antibiotic in the same concentration, up to 72%. The developed composite is a promising material for the treatment of biofilm-associated inflammations.


Assuntos
Biofilmes/crescimento & desenvolvimento , Carbonatos/química , Ciprofloxacina/farmacologia , Escherichia coli/crescimento & desenvolvimento , Magnetismo , Nanocompostos/administração & dosagem , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Escherichia coli/efeitos dos fármacos , Nanocompostos/química , Staphylococcus aureus/efeitos dos fármacos
20.
Molecules ; 26(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202191

RESUMO

Twenty-two novel, variously substituted nitroazetidines were designed as both sulfonamide and urethane vinylogs possibly endowed with antimicrobial activity. The compounds under study were obtained following a general procedure recently developed, starting from 4-nitropentadienoates deriving from a common ß-nitrothiophenic precursor. While being devoid of any activity against fungi and Gram-negative bacteria, most of the title compounds performed as potent antibacterial agents on Gram-positive bacteria (E. faecalis and three strains of S. aureus), with the most potent congener being the 1-(4-chlorobenzyl)-3-nitro-4-(p-tolyl)azetidine 22, which displayed potency close to that of norfloxacin, the reference antibiotic (minimum inhibitory concentration values 4 and 1-2 µg/mL, respectively). Since 22 combines a relatively efficient activity against Gram-positive bacteria and a cytotoxicity on eucharyotic cells only at 4-times higher concentrations (inhibiting concentration on 50% of the cultured eukaryotic cells: 36 ± 10 µM, MIC: 8.6 µM), it may be considered as a promising hit compound for the development of a new series of antibacterials selectively active on Gram-positive pathogens. The relatively concise synthetic route described herein, based on widely available starting materials, could feed further structure-activity relationship studies, thus allowing for the fine investigation and optimization of the toxico-pharmacological profile.


Assuntos
Antibacterianos , Azetidinas , Enterococcus faecalis/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Azetidinas/síntese química , Azetidinas/química , Azetidinas/farmacologia , Relação Dose-Resposta a Droga , Avaliação de Medicamentos , Células Hep G2 , Humanos , Relação Estrutura-Atividade
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