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1.
Pestic Biochem Physiol ; 158: 185-200, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378356

RESUMO

The present work describes the antimicrobial action of 25 monoterpenes (six hydrocarbons, five ketones, two aldehydes, six alcohols and six acetate analogues) against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and antifungal activity against Aspergillus flavus. The antibacterial activity was evaluated by broth microdilution technique as a minimum inhibitory concentration (MIC) and the antifungal activity was performed by mycelia radial growth technique as the effective concentration causing 50% inhibition of the mycelial growth (EC50). The results showed that thymol and α-terpineol were the most potent against E. coli (MIC = 45 and 55 mg/L, respectively) and S. aureus (MIC = 135 and 225 mg/L, respectively). The results also showed that thymol displayed the maximum antifungal action against A. flavus with EC50 20 mg/L. Furthermore, the antioxidant activity was determined using N,N-dimethyl-1,4-phenylenediamine (DMPD) and the results showed that geraniol were the most potent compound (IC50 = 19 mg/L). Molecular docking studies indicated that the compounds displayed different binding interactions with the amino acid residues at the catalytic sites of N5-carboxyaminoimidazole synthetase and oxysterol binding protein Osh4 enzymes. Non-covalent interactions including van der Waals, hydrogen bonding as well as hydrophobic were observed between the compounds and the enzymes. A significant relationship was found between the docking score and the biological activity of the tested monoterpenes compared to the ceftriaxone and carbendazim as standard bactericide and fungicide, respectively. In silico ADMET properties were also performed and displayed potential for the development of promising antimicrobial agents. For these reasons, these compounds may be considered as potential ecofriendly alternatives in food preservation to delay or prevent the microbial infection and prolong the shelf life of food products.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Monoterpenos/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Cicloexenos/química , Cicloexenos/farmacologia , Escherichia coli/efeitos dos fármacos , Hidrocarbonetos/química , Hidrocarbonetos/farmacologia , Testes de Sensibilidade Microbiana , Monoterpenos/química , Monoterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos
2.
Bone Joint J ; 101-B(7): 848-851, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31256673

RESUMO

AIMS: The aims of this study were to compare the mean duration of antibiotic release and the mean zone of inhibition between vancomycin-loaded porous tantalum cylinders and antibiotic-loaded bone cement at intervals, and to evaluate potential intrinsic antimicrobial properties of tantalum in an in vitro medium environment against methicillin-sensitive Staphylococcus aureus (MSSA). MATERIALS AND METHODS: Ten porous tantalum cylinders and ten cylinders of cement were used. The tantalum cylinders were impregnated with vancomycin, which was also added during preparation of the cylinders of cement. The cylinders were then placed on agar plates inoculated with MSSA. The diameter of the inhibition zone was measured each day, and the cylinders were transferred to a new inoculated plate. Inhibition zones were measured with a Vernier caliper and using an automated computed evaluation, and the intra- and interobserver reproducibility were measured. The mean inhibition zones between the two groups were compared with Wilcoxon's test. RESULTS: MSSA was inhibited for 12 days by the tantalum cylinders and for nine days by the cement cylinders. At day one, the mean zone of inhibition was 28.6 mm for the tantalum and 19.8 mm for the cement group (p < 0.001). At day ten, the mean zone of inhibition was 3.8 mm for the tantalum and 0 mm for the cement group (p < 0.001). The porous tantalum cylinders soaked only with phosphate buffered solution showed no zone of inhibition. CONCLUSION: Compared with cement, tantalum could release antibiotics for longer. Further studies should assess the advantages of using antibiotic-loaded porous tantalum implants at revision arthroplasty. Cite this article: Bone Joint J 2019;101-B:848-851.


Assuntos
Antibacterianos/administração & dosagem , Cimentos para Ossos , Sistemas de Liberação de Medicamentos , Staphylococcus aureus/efeitos dos fármacos , Tantálio , Vancomicina/administração & dosagem , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Artroplastia de Substituição/instrumentação , Humanos , Prótese Articular , Testes de Sensibilidade Microbiana , Variações Dependentes do Observador , Infecções Relacionadas à Prótese/prevenção & controle , Fatores de Tempo , Vancomicina/farmacologia , Vancomicina/uso terapêutico
3.
J Agric Food Chem ; 67(30): 8382-8392, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31271032

RESUMO

Staphylococcus aureus is a common pathogen that can cause life-threatening infections. Treatment of antibiotic-resistant S. aureus infection needs effective antibacterial agents. Thymol, a generally recognized safe natural compound, has potential as an alternative to treat S. aureus infections. However, the targets and mechanisms of action of thymol were not fully understood. Bioinformatics analysis showed that IolS, a predicted aldo-keto reductase (AKR) in S. aureus, could be a potential target of thymol. Isothermal titration calorimetry (ITC) analysis demonstrated that thymol directly binds IolS and amino acid residues (Y30 and L33) are essential for such binding. Deletion of IolS or mutation of Y30A and L33A reduced the bactericidal activity of thymol at the concentration of 200 µg/mL, suggesting that thymol mediates bactericidal activity via binding with IolS. Biochemical analysis showed that addition of thymol significantly increased AKR activity of IolS from 1.6 ± 0.1 to 2.4 ± 0.2 U (p < 0.05). The content of NADPH within S. aureus cells decreased significantly from 105 ± 5 to 72 ± 3 pmol/108 cells (p < 0.05) following thymol treatment at the concentration of 200 µg/mL. Importantly, addition of NADPH could alleviate the bactericidal effect of thymol on S. aureus, indicating that the depletion of NADPH is responsible for thymol-mediated bactericidal activity. Overall, these results demonstrated that thymol could directly bind IolS and increase its AKR activity, leading to the depletion of NADPH and bactericidal effect. AKR activity of IolS could be a promising target for the development of new antimicrobials.


Assuntos
Aldo-Ceto Redutases/antagonistas & inibidores , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , NADP/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Timol/farmacologia , Aldo-Ceto Redutases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética
4.
Chem Biodivers ; 16(8): e1900317, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31264344

RESUMO

Four new diterpenoids named cuceolatins A-D, including three labdane-type (1-3) and one abietane-type (4) as well as three known labdane analogs (5-7), were reported from the leaves of Cunninghamia lanceolata. Structural assignments for these compounds were conducted by analyses of spectroscopic data, and their absolute configurations were determined by time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculations. Among them, the abietane-type diterpenoid (11-hydroxy-12-methoxyabieta-8,11,13-trien-3-one (4)) showed significant cytotoxicity against human MDA-MB-231, MCF-7, and HeLa tumor cell lines with IC50 measurements of 4.3, 2.8 and 4.5 µm, respectively, while the labdane-type diterpenoids with a 4α-carboxy group (1-3 and 5) exhibited moderate antibacterial activity towards Bacillus subtilis and Staphylococcus aureus with IC50 values all below 25 µm.


Assuntos
Cunninghamia/química , Diterpenos/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Cunninghamia/metabolismo , Teoria da Densidade Funcional , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Diterpenos de Abietano/química , Diterpenos de Abietano/isolamento & purificação , Diterpenos de Abietano/farmacologia , Humanos , Conformação Molecular , Folhas de Planta/química , Folhas de Planta/metabolismo , Staphylococcus aureus/efeitos dos fármacos
5.
Onderstepoort J Vet Res ; 86(1): e1-e9, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291733

RESUMO

South Africa is a large country of approximately 1.22 million km2, made up of nine provinces with three climatic zones. Farming in the country is mostly defined by regional differences. Of the different organisms isolated from milk samples of dairy cows, Staphylococcus aureus poses a challenge to maintain udder health and wholesome dairy products for human consumption. Antibiotic resistant bacteria are therefore a potential health hazard. The objective of this study was to investigate the seasonal and regional relationships of antibiotic resistance of S. aureus, of which little is known. This study was undertaken to evaluate a data set of 3410 S. aureus isolates, taken from milk samples with a somatic cell count of > 400 000 cells/mL from commercial dairy herds. These isolates were tested for antimicrobial susceptibility using the Kirby Bauer method for ampicillin, cloxacillin, penicillin G, clindamycin, oxy-tetracycline, cephalexin, cefuroxime and tylosin. The samples were from 830 dairy herds, out of the estimated 2000 commercial dairy herds in South Africa. All the antibiotics tested, except for cephalosporins, showed a predicted prevalence of resistance of above 50% in most provinces, which is a concern. The lowest prevalence of resistance to the majority of the categories of antibiotics tested was present in KwaZulu-Natal during spring. The cephalosporins had the lowest levels of prevalence of bacterial resistance in Gauteng during winter. Resistance patterns of S. aureus to the eight antibiotics varied in the different seasons and provinces, possibly because of different weather conditions, and the action and spectrum of antibiotics.


Assuntos
Antibacterianos/farmacologia , Indústria de Laticínios , Mastite Bovina/epidemiologia , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/efeitos dos fármacos , Animais , Bovinos , Clima , Demografia , Farmacorresistência Bacteriana , Feminino , Mastite Bovina/microbiologia , Testes de Sensibilidade Microbiana/veterinária , Prevalência , África do Sul/epidemiologia , Infecções Estafilocócicas/epidemiologia
6.
J Agric Food Chem ; 67(29): 8191-8196, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31282662

RESUMO

Conversion of free fatty acids into monoacylglycerol gives rise to new structural properties, particularly amphipathic property. Therefore, monoacylglycerols are widely used in pharmaceutical and food industries and are also reported to facilitate better absorption into the human body. A functional fatty acid when transformed into a monoacylglycerol will possibly conserve both the original functionality and amphipathic property. The compound 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was generated from oleic acid by Pseudomonas aeruginosa PR3 and was known to contain antimicrobial activities against a broad range of food-borne and plant pathogenic bacteria. Here, we attempted to convert DOD into its monoacylglycerol form using lipase for producing an amphipathic antibacterial agent. Consequently, the monoacylglycerol of DOD (DOD-MAG) was successfully produced by coincubating DOD, glycerol, and lipase at 30 °C. The maximum conversion yield reached 70% after 12 h of incubation. Antibacterial activity of DOD-MAG was enhanced by 8 times from the original activity of DOD against food-borne bacteria.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Monoglicerídeos/química , Ácidos Oleicos/química , Ácidos Oleicos/farmacologia , Pseudomonas aeruginosa/química , Antibacterianos/metabolismo , Microbiologia de Alimentos , Ácidos Oleicos/metabolismo , Pseudomonas aeruginosa/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
7.
J Photochem Photobiol B ; 197: 111539, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31301638

RESUMO

Treatment of burn injury is clinically challenging one, therefore several steps and noteworthy approaches have been taken to improve wound mechanisms. Citrus pectin plays a stabilizing agent to synthesis of ZnO nanoparticles (ZnO NPs). The present study is focused on ZnO loaded collagen/chitosan nanofibrous were synthesized by electrospinning method using ZnO NPs. The chemical structure, phase purity and morphological observation were investigated under spectroscopic and mircoscopic techniques and demonstrated their suitable properties as a wound healing material. In addition, that prepared nanoparticles loaded biopolymeric fibrous nanomaterial showed suitable antibacterial activity against S. aureus and E. coli bacterial pathogens and also in vitro studies was confirmed the enhanced proliferation, cell viability and biocompatibility. In vitro evaluations have been exhibited acceptable cell proliferation is observed throughout the ZnO loaded Coll/CS nanofibrous within 3 days, which was comparable to the control material. In vivo wound healing ability was monitored on the rat wound experimental model. From the in vivo observations, revealed that the loaded of ZnO NPs with Coll/CS nanofibrous can effectively quicken wound healing mechanism, expressed in the initial stage healing process. These results suggest that ZnO loaded collagen/chitosan nanofibrous is a potential candidate for wound healing applications with enhanced biological properties.


Assuntos
Queimaduras/patologia , Quitosana/química , Colágeno/química , Nanopartículas Metálicas/química , Nanofibras/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bacteriemia/prevenção & controle , Queimaduras/veterinária , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Nanofibras/uso terapêutico , Nanofibras/toxicidade , Ratos , Pele/efeitos dos fármacos , Pele/patologia , Staphylococcus aureus/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Óxido de Zinco/química
8.
Pharm Res ; 36(8): 122, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31218556

RESUMO

PURPOSE: A non-propellant based foam (NPF) system was developed incorporating the antibiotics, pectin capped green nano-silver and sulfadiazine (SD) for the topical treatment of burn wounds as a convenient alternative to the existing therapies. METHODS: NPF were prepared using various surfactants and oils forming a nanoemulsion. Anti-microbial studies by resazurin microtitre assay, ex vivo diffusion, in vivo skin permeation and deposition studies, and acute irritation studies were carried out. NPF was applied onto secondary thermal wounds manifested on mice models followed by macroscopic and histological examinations. RESULTS: NPF had an average globule size of <75 nm. The viscosity was ~10 cP indicating the feasibility of expulsion from the container upon actuation. With no skin irritation, the foams showed a higher skin deposition of SD. A high contraction and an evident regeneration of the skin tissue upon treatment with NPF indicated a good recovery from the thermal injury was apparent from the histology studies. CONCLUSION: NPF represents an alternative topical formulation that can be employed as a safe and effective treatment modality for superficial second degree (partial thickness) burn wounds. With a minimal requirement of mechanical force, the no-touch application of NPF makes it suitable for sensitive and irritant skin surfaces.


Assuntos
Antibacterianos/farmacologia , Queimaduras/tratamento farmacológico , Nanopartículas Metálicas/química , Prata/química , Sulfadiazina/farmacologia , Cicatrização/efeitos dos fármacos , Administração Tópica , Animais , Antibacterianos/administração & dosagem , Queimaduras/patologia , Queimaduras/fisiopatologia , Composição de Medicamentos/métodos , Quimioterapia Combinada , Emulsões , Escherichia coli/efeitos dos fármacos , Química Verde , Humanos , Masculino , Camundongos , Óleos/química , Tamanho da Partícula , Permeabilidade , Pele/efeitos dos fármacos , Pele/patologia , Pele/fisiopatologia , Staphylococcus aureus/efeitos dos fármacos , Sulfadiazina/administração & dosagem , Tensoativos/química
9.
Pan Afr Med J ; 32: 103, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31223393

RESUMO

Introduction: Staphylococcus aureus is an important pathogen responsible for hospital and community acquired infection(s). Emerging resistance to methicillin in this organism has left physicians with few therapeutic alternatives to treat infections caused by it. This study was aimed at determining the antibiotic susceptibility patterns of Staphylococcus aureus strains isolated at the Yaounde Central Hospital, Cameroon. Methods: from January 2014 to November 2016, a total of 250 non repeated strains were isolated from various clinical specimens. Isolates and antibiotic susceptibility profiles were identified through standard microbiological techniques. Results: methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) accounted respectively for 80% (201/205) and 20% (49/205) of the total strains isolated. MRSA strains displayed high resistance to cefoxitin (100%), cotrimoxazole (89%), vancomycin (79.7%), lincomycin (70.3%), tobramycin (72.5%), doxycycline (68.0%), kanamycin (69.7%) and erythromycin (55.7%). In contrast, a high susceptibility was observed with rifampicin (82.6%). KTG (42.3%) and constitutive MLSB (17.4%) were the most frequent phenotypes recorded. Conclusion: our results show that the carriage of acquired MRSA infections predominates in this population. Despite the noticeable multiresistance of MRSA strains to antibiotics, rifampicin remains the drugs of choice for the therapy of acquired MRSA infections in this setting. In order to slow down antimicrobial resistance, surveillance studies for antimicrobial susceptibility remains essential to identify resistance and inform policy on resistance.


Assuntos
Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Camarões/epidemiologia , Estudos Transversais , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Estudos Prospectivos , Estudos Retrospectivos , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação
10.
Chemotherapy ; 64(1): 17-21, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167190

RESUMO

Prolonged intermittent renal replacement therapy (PIRRT) is an increasingly adopted method of renal replacement in critically ill patients. Like continuous renal replacement therapy, PIRRT can alter the pharmacokinetics (PK) of many drugs. In this setting, dosing data for antibiotics like benzylpenicillin are lacking. In order to enable clinicians to prescribe benzylpenicillin safely and effectively, knowledge of the effects of PIRRT on the plasma PK of benzylpenicillin is required. Herein, we describe the PK of benzylpenicillin in 2 critically ill patients on PIRRT for the treatment of penicillin-susceptible Staphylococcus aureus bacteremia complicated by infective endocarditis. Blood samples were taken for each patient taken over dosing periods during PIRRT and off PIRRT. Two-compartment PK models described significant differences in the mean clearance of benzylpenicillin with and without PIRRT (6.61 vs. 3.04 L/h respectively). We would suggest a benzylpenicillin dose of 1,800 mg (3 million units) every 6-h during PIRRT therapy as sufficient to attain PK/pharmacodynamic target.


Assuntos
Antibacterianos/farmacocinética , Penicilina G/farmacocinética , Lesão Renal Aguda/etiologia , Lesão Renal Aguda/terapia , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bacteriemia/complicações , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Relação Dose-Resposta a Droga , Meia-Vida , Humanos , Masculino , Pessoa de Meia-Idade , Penicilina G/farmacologia , Penicilina G/uso terapêutico , Terapia de Substituição Renal , Sepse/complicações , Sepse/diagnóstico , Sepse/tratamento farmacológico , Sepse/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Resultado do Tratamento
11.
Chemotherapy ; 64(1): 22-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167192

RESUMO

BACKGROUND: Pantothenate, the fundamental precursor to coenzyme A, is required for optimal growth and virulence of microbial pathogens. It is synthesized by the enzyme-catalyzed condensation of ß-alanine and pantoate, which has shown susceptibility to inhibition by analogs of its molecular constituents. Accordingly, analogs of ß-alanine are gaining inquiry as potential antimicrobial chemotherapeutics. METHODS: We synthesized and evaluated 35 derivatives of ß-alanine, substituted at the α, ß, amine, and carboxyl sites, derived from in silico, dynamic molecular modeling to be potential competitive inhibitors of pantothenate synthetase. Employing the Clinical Laboratory Standards M7-A6 broth microdilution method, we tested these for inhibition of growth in Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. RESULTS: All compounds proved entirely ineffective in all species tested, with no inhibition of growth being observed up to 200 µM/mL. CONCLUSIONS: Upon revision of the literature, we conclude that high enzyme selectivity or external salvage mechanisms may render this strategy futile against most bacteria.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeo Sintases/metabolismo , beta-Alanina/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Peptídeo Sintases/antagonistas & inibidores , Estrutura Terciária de Proteína , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia
12.
Environ Pollut ; 249: 1106-1114, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31146316

RESUMO

Graphene oxide (GO) has been demonstrated to be key component for diverse applications. However, their potential environmental reactivity, fate and risk have not been fully evaluated to date. In this study, we investigated the photochemical reactivity of four types of GO with different oxidation degrees in aqueous environment, and their related toxicity to two bacterial models Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was further compared. After UV-irradiation, a large amount of oxygen functional groups on GO were reduced and the electronic conjugations within GO were restored as indicated by UV-visible absorption spectra, X-ray photoelectron spectroscopy and Raman spectroscopy analysis. Moreover, the higher the oxidation degree of the pristine GO was, the more obvious of the photo-transformation changes were. In order to further reveal the photochemical reactivity mechanisms, the reactive oxygen species (ROS) generation of GO was monitored. The quantity of ROS including singlet oxygen (1O2), superoxide anions (O2·-), and hydroxyl radicals (·OH) increased with increasing oxidation degree of GO, which was in accordance with the previous characterization results. Scanning electron microscopy and cell growth analyses of E. coli and S. aureus showed that the photochemical transformation enhanced the toxicity of GO, which might be due to an increase in functional group density. The higher conductivity of the reduced graphene oxide (RGO) was responsible for its stronger toxicity than GO through membrane damage and oxidative stress to bacteria. This study revealed that the oxidation degrees play important roles in photochemical transformation and the resulting toxicity of GO, which is helpful for understanding the environmental behaviors and risks of GO in aquatic environments.


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Escherichia coli/crescimento & desenvolvimento , Grafite/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Poluentes Químicos da Água/efeitos da radiação
13.
Int J Nanomedicine ; 14: 3345-3360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190796

RESUMO

Background: Designing a wound dressing that effectively prevents multi-drug-resistant bacterial infection and promotes angiogenesis and re-epithelialization is of great significance for wound management. Methods and results: In this study, a biocompatible composite membrane comprising biomimetic polydopamine-modified eggshell membrane nano/microfibres coated with KR-12 antimicrobial peptide and hyaluronic acid (HA) was developed in an eco-friendly manner. The physicochemical properties of the composite membrane were thoroughly characterized, and the results showed that the surface hydrophilicity and water absorption ability of the composite membrane were improved after the successive conjugation of the HA and the KR-12 peptide. Furthermore, the in vitrobiological results revealed that the composite membrane had excellent antibacterial activity against Gram-positive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli, and it could prevent MRSA biofilm formation on its surface. Additionally, it promoted the proliferation of keratinocytes and human umbilical vein endothelial cells and increased the secretion of VEGF. Finally, an in vivo animal study indicated that the composite membrane could promote wound healing via accelerating angiogenesis and re-epithelialization, which were demonstrated by the enhanced expression of angiogenetic markers (CD31 and VEGF) and keratinocyte proliferation marker (PCNA), respectively. Conclusion: These results indicated that the composite membrane is a potential candidate of wound dressings.


Assuntos
Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Casca de Ovo/química , Ácido Hialurônico/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Peptídeos/farmacologia , Reepitelização/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Galinhas , Escherichia coli/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Peptídeos/química , Porosidade , Staphylococcus aureus/efeitos dos fármacos
14.
Int J Nanomedicine ; 14: 3439-3454, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190802

RESUMO

Objective: The microbial, physico-chemical and optical corruptions threaten a variety of foods and drugs and consequently the human biological safety and its accessible resources. The humanbeing's tendency towards bio-based materials and natural plant-extracts led to an increase in the usage of antimicrobial biocomposites based on medicinal herbs. Miswak (Salvadora persica L.) extract (SPE) has been proved effective for its antimicrobial and other biological activities. Therefore, in this study, titanium dioxide (TiO2) nanoparticles (TONP) and SPE were applied to fabricate antimicrobial carboxymethyl cellulose (Na-CMC) based bio-nanocomposites which would simultaneously promote some thermo-physical and barrier properties. Methods: CMC-neat film (C1), CMC/TONP-2% (C2) and CMC/TONP-2% with 150, 300 and 450 mg/mL SPE (SPE150, SPE30 and SPE450, respectively) were fabricated. The physical and mechanical properties; elemental mapping analysis (MAP), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA-DTG); fourier transform infrared (FTIR), energy-dispersive X-ray (EDX) and UV-vis spectroscopies were done to further validate the results. Results: Addition of TONP (2%) improved the blocking of UV light at 280 nm while SPE-containing nanocomposites completely blocked it. FTIR, XRD and SEM confirmed the formation of homogeneous films and high miscibility of applied materials. TONP led to an increase in Young's modulus (YM) and stress at break (SB) while SPE decreased them and enhanced the elongation to break (EB) (flexibility) of the active nanocomposites. Compared to CMC-film, the thermo-gravimetric analysis (TGA-DTG) showed a higher thermal stability for CMC/TONP and CMC/TONP/SPE nanocomposites. The EDX spectroscopy and elemental mapping analysis (MAP) proved the existence and well-distributedness of Na, K, Cl, S, Ti, F and N elements in SPE-activated nanocomposites. The pure SPE and SPE-activated nanocomposites showed a favorable antimicrobial activity against both gram-positive (Staphylococcus aureus) and negative (Escherichia coli) bacteria. Conclusion: The CMC-TiO2-SPE nanocomposites were homogeneously produced. Combination of TiO2 nanoparticles and dose-dependent SPE led to an improvement of thermal stability, and high potential in antimicrobial and UV-barrier properties. These results can generally highlight the role of the fabricated antimicrobial bio-nanocomposites as a based for different applications especially in food/drug packaging or coating.


Assuntos
Antibacterianos/farmacologia , Nanocompostos/química , Nanopartículas/química , Extratos Vegetais/farmacologia , Salvadoraceae/química , Temperatura Ambiente , Titânio/química , Elementos , Humanos , Umidade , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Permeabilidade , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Vapor , Termogravimetria , Difração de Raios X
15.
Int J Nanomedicine ; 14: 3533-3541, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190810

RESUMO

Background: Himalayan honey, a natural product of wild honey bees found in the Himalayan mountains of Nepal, has been used in medicine for many years. The successful development of nanotechnology and beneficial effects of honey would bring a new opportunity to synthesize hybrid nanomaterials for biomedical applications. Thus, the purpose of this study was to load Himalayan honey onto iron oxide nanoparticles (IO-NPs) and study their antioxidant and antimicrobial activities. Methods: Himalayan honey loaded iron oxide nanoparticles (HHLIO-NPs) were synthesized and X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were performed for characterization. UV-VIS spectra confirmed the loading of honey onto nanoparticles. The antioxidant activity of these nanoparticles was studied against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical system. We also tested antimicrobial activity of HHLIO-NPs using well diffusion method towards both Gram-positive and Gram-negative bacterial strains of Staphylococus aureus & Escherichia coli. Results: From XRD analysis, the average particle size was found to be 33-40 nm. The SEM images show needle shape porous structures of HHLIO-NPs compared to free IO-NPs indicating the surfactant-like behaviour of honey. In DPPH radical system, the scavenging activities of Himalayan honey (HH), free IO-NPs and HHLIO-NPs ranged 7.93-35.99%, 11.02-52.02% and 16.10-80.52% respectively, with corresponding IC50 values of 1.36 mg/mL, 1.09 mg/mL and 0.52 mg/mL. The antimicrobial property of all test samples showed a noteworthy inhibition on both bacterial strains. However, the HH and HHLIO-NPs exhibited strong antibacterial activity against E. coli. Conclusion: This work reveals that the biological activity of HH is enhanced significantly after loading into IO-NPs. Thus, the HHLIO-NPs would be a promising alternative for antioxidant and antimicrobial agents.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Compostos Férricos/química , Mel , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Concentração Inibidora 50 , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
16.
Int J Nanomedicine ; 14: 3583-3600, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190813

RESUMO

Purpose: This study aimed to decorate the surface of TiO2 nanotubes (TiO2 NTs) grown on medical grade Ti-6Al-4V alloy with an antimicrobial layer of nano zinc oxide particles (nZnO) and then determine if the antimicrobial properties were maintained with a final layer of nano-hydroxyapatite (HA) on the composite. Methods: The additions of nZnO were attempted at three different annealing temperatures: 350, 450 and 550 °C. Of these temperatures, 350°C provided the most uniform and nanoporous coating and was selected for antimicrobial testing. Results: The LIVE/DEAD assay showed that ZnCl2 and nZnO alone were >90% biocidal to the attached bacteria, and nZnO as a coating on the nanotubes resulted in around 70% biocidal activity. The lactate production assay agreed with the LIVE/DEAD assay. The concentrations of lactate produced by the attached bacteria on the surface of nZnO-coated TiO2 NTs and ZnO/HA-coated TiO2 NTs were 0.13±0.03 mM and 0.37±0.1 mM, respectively, which was significantly lower than that produced by the bacteria on TiO2 NTs alone, 1.09±0.30 mM (Kruskal-Wallis, P<0.05, n=6). These biochemical measurements were correlated with electron micrographs of cell morphology and cell coverage on the coatings. Conclusion: nZnO on TiO2 NTs was a stable and antimicrobial coating, and most of the biocidal properties remained in the presence of nano-HA on the coating.


Assuntos
Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Nanotubos/química , Staphylococcus aureus/efeitos dos fármacos , Titânio/química , Óxido de Zinco/química , Zinco/farmacologia , Anti-Infecciosos/química , Preparações de Ação Retardada/química , Diálise , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotubos/ultraestrutura , Propriedades de Superfície
17.
Georgian Med News ; (289): 139-143, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31215896

RESUMO

Determination of Ag nanoparticles impact on microorganisms causative agents of purulent-inflammatory processes was carried out and it was stated that the greatest significance of growth inhibition zone was found in Staphylococcus aureus and Streptococcus pyogenes with sample length from 1 to 6 mm and Escherichia coli with 5-6 mm sample length. The investigated strains in an amount 104 - 106 CFU/ml were sensitive to Аg nanoparticles activity, but at concentration 108 CFU/ml and more all strains were found persistent to samples of various length. The ability to form biofilms with planktonic cells of microorganisms under Ag nanoparticles activity sufficiently reduced from 3.4 (Candida albicans) to 5.5 (Klebsiella pneumonia) in investigated strains. The disorganization of daily biofilms was found in determining of Ag nanoparticles impact on formed biofilms of microorganisms.


Assuntos
Biofilmes , Nanopartículas Metálicas , Staphylococcus aureus , Antibacterianos , Biofilmes/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Prata , Staphylococcus aureus/efeitos dos fármacos
18.
Int J Food Microbiol ; 304: 19-31, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31151072

RESUMO

Reducing salt content in foods such as cheeses, while limiting the growth of spoilage microorganisms and foodborne pathogens, is a difficult challenge. One method that may prove useful is use of staphylococcins, which are bacteriocins produced by staphylococci. Therefore, staphylococcin antimicrobial activity against six strains of S. aureus isolated from cheese was tested aiming at their industrial application in biopreservation of Minas fresh (Frescal) cheese with reduced sodium content. Three staphylococcins were selected for these tests: Pep 5, aureocin A53 and lysostaphin. All three staphylococcins proved to be bacteriolytic against all six strains of S. aureus. The antimicrobial activity of the partially purified staphylococcins was subsequently investigated against strains S. aureus Q1 and QJ3 in cheese matrices (6.0 log CFU/g) with different NaCl contents (control, a 25% reduction, and a 50% reduction), kept under refrigeration at 4 °C, for 21 days. Both strains were shown to be of concern for food industry as they carry the SEA, SEB and SEH enterotoxin genes, and are resistant to ß-lactam drugs and moderate biofilm formers when grown in TSB. When used singly, Pep5, aureocin A53 and lysostaphin reduced approximately 95%, 99% and 99.99% of the viable cell counts, respectively, irrespective of the sodium content of the cheese matrix. The combined action of aureocin A53 and Pep5 resulted in an additional and significant reduction (p < 0.05) of ~1.0 log CFU/g when compared with the reduction caused by the use of either one singly. The combined action of lysostaphin and aureocin A53 or lysostaphin and Pep5 resulted in a reduction similar to or slightly smaller (p > 0.05) than that observed when lysostaphin was employed singly. Lysostaphin also proved to reduce the number of the staphylococcal viable cells to a level (~ 2.0 log CFU/g) at which enterotoxin production should not reach a sufficient quantity to cause food poisoning. Therefore, lysostaphin may have a practical application in the food industry to control staphylococcal contamination of Minas fresh cheese with a sodium content reduced up to 50%, providing consumers with more safe options to reduce their intake of sodium.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Queijo/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Lisostafina/farmacologia , Peptídeos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Enterotoxinas/análise , Doenças Transmitidas por Alimentos/microbiologia , Cloreto de Sódio/análise , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/metabolismo
19.
Ultrason Sonochem ; 57: 108-115, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31208605

RESUMO

Efficiency of blue (462 ±â€¯3 nm) light emitting diode (LED) illumination to inactivate Escherichia coli and Staphylococcus aureus in the presence of exogenous photosensitizer (curcumin) was studied in freshly squeezed orange juice. Further, the combinational effect of ultrasound (US), photosensitizer (PS) and blue light (BL) on inactivation of microbes was evaluated. The effect of process parameters such as concentration of PS, US and volume of the juice on E. coli and S. aureus inactivation was also investigated. The US alone and PS + BL treatments resulted in 3.02 ±â€¯0.52 and 1.06 ±â€¯0.13 log reduction of E. coli; 0.18 ±â€¯0.14 and 2.34 ±â€¯0.13 log reduction of S. aureus, respectively. The combination of PS + US + BL treatment at optimized conditions resulted in 2.35 ±â€¯0.16 log reduction of S. aureus. An additive effect on the inactivation of E. coli (4.26 ±â€¯0.32 log reduction) was observed with PS + US + BL combination treatment. The US treatment showed significant change in cloud value, colour and browning index of orange juice. The combinational non-thermal processes (PS + BL and PS + US + BL) did not have any significant effect on total phenolic content, total flavonoid content, and hesperidin content of the orange juice. However, these processes affected ascorbic acid content and antioxidant activity negatively. Thus, this study indicated that photodynamic inactivation of E. coli and S. aureus using LED-based photosensitization in fruit juices could be a potential method for microbial inactivation. Nevertheless, the effect on quality parameters needs to be considered while optimizing the process.


Assuntos
Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos da radiação , Microbiologia de Alimentos , Sucos de Frutas e Vegetais/microbiologia , Luz , Fármacos Fotossensibilizantes/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/efeitos da radiação , Ondas Ultrassônicas , Antioxidantes/análise , Ácido Ascórbico/análise , Contagem de Colônia Microbiana , Escherichia coli/isolamento & purificação , Flavonoides/análise , Sucos de Frutas e Vegetais/análise , Hesperidina/análise , Valor Nutritivo , Fenóis/análise , Espectrofotometria/métodos , Staphylococcus aureus/isolamento & purificação
20.
Int J Nanomedicine ; 14: 3861-3874, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213806

RESUMO

Purpose: Infections associated with medical devices that are caused by biofilms remain a considerable challenge for health care systems owing to their multidrug resistance patterns. Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus can result in life-threatening situations which are tough to eliminate by traditional methods. Antimicrobial photodynamic inactivation (aPDT) constitutes an alternative method of killing deadly pathogens and their biofilms using reactive oxygen species (ROS). This study investigated the efficacy of enhanced in vitro aPDT of P. aeruginosa and S. aureus using malachite green conjugated to carboxyl-functionalized multi-walled carbon nanotubes (MGCNT). Both the planktonic cells and biofilms of test bacteria were demonstrated to be susceptible to the MGCNT conjugate. These MGCNT conjugates may thus be employed as a facile strategy for designing antibacterial and anti-biofilm coatings to prevent the infections associated with medical devices. Methods: Conjugation of the cationic dye malachite green to carbon nanotube was studied by UV-visible spectroscopy, high-resolution transmission electron microscopy, and Fourier transform infrared spectrometry. P. aeruginosa and S. aureus photodestruction were studied using MGCNT conjugate irradiated for 3 mins with a red laser of wavelength 660 nm and radiant exposure of 58.49 J cm-2. Results: Upon MGCNT treatment, S. aureus and P. aeruginosa were reduced by 5.16 and 5.55 log10 , respectively. Compared to free dye, treatment with MGCNT afforded improved phototoxicity against test bacteria, concomitant with greater ROS production. The results revealed improved biofilm inhibition, exopolysaccharide inhibition, and reduced cell viability in test bacteria treated with MGCNT conjugate. P. aeruginosa and S. aureus biofilms were considerably reduced to 60.20±2.48% and 67.59±3.53%, respectively. Enhanced relative MGCNT phototoxicity in test bacteria was confirmed using confocal laser scanning microscopy. Conclusion: The findings indicated that MGCNT conjugate could be useful to eliminate the biofilms formed on medical devices by S. aureus and P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Nanotubos de Carbono/química , Fotoquimioterapia , Plâncton/citologia , Plâncton/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Corantes de Rosanilina/farmacologia , Staphylococcus aureus/fisiologia , Cinética , Peroxidação de Lipídeos/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Nanotubos de Carbono/ultraestrutura , Pseudomonas aeruginosa/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos
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