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Polyelectrolyte-drug complexes are interesting alternatives to improve unfavorable drug properties. Vancomycin (VAN) is an antimicrobial used in the treatment of methicillin-resistant Staphylococcus aureus pulmonary infections in patients with cystic fibrosis. It is generally administered intravenously with a high incidence of adverse side effects, which could be reduced by intrapulmonary administration. Currently, there are no commercially available inhalable formulations containing VAN. Thus, the present work focuses on the preparation and characterization of an ionic complex between hyaluronic acid (HA) and VAN with potential use in inhalable formulations. A particulate-solid HA-VAN25 complex was obtained by spray drying from an aqueous dispersion. FTIR spectroscopy and thermal analysis confirmed the ionic interaction between HA and VAN, while an amorphous diffraction pattern was observed by X-ray. The powder density, geometric size and morphology showed the suitable aerosolization and aerodynamic performance of the powder, indicating its capability of reaching the deep lung. An in vitro extended-release profile of VAN from the complex was obtained, exceeding 24 h. Microbiological assays against methicillin-resistant and -sensitive reference strains of Staphylococcus aureus showed that VAN preserves its antibacterial efficacy. In conclusion, HA-VAN25 exhibited interesting properties for the development of inhalable formulations with potential efficacy and safety advantages over conventional treatment.
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Gentamicin (GEN), a widely used broad-spectrum antibiotic, faces challenges amid the global emergency of antimicrobial resistance. This study aimed to explore the synergistic effects of zinc oxide nanoparticles (ZnO NPs) in combination with GEN on the bactericidal activity against various bacterial strains. Results showed ZnO NPs with MICs ranging from 0.002 to 1.5 µg/mL, while the precursor salt displayed a MIC range of 48.75-1560 µg/mL. Chitosan (CS)-capped ZnO NPs exhibited even lower MICs than their uncapped counterparts, with the CS-capped synthesized ZnO NPs demonstrating the lowest values. Minimal bactericidal concentrations (MBC) aligned with MIC trends. Combinations of CS-capped synthesized ZnO NPs and GEN proved highly effective, inhibiting bacterial growth at significantly lower concentrations than GEN or ZnO NPs alone. This phenomenon may be attributed to the conformation of CS on the ZnO NPs' surface, enhancing the positive particle surface charge. This possibly facilitates a more effective interaction between ZnO NPs and microorganisms, leading to increased accumulation of zinc and GEN within bacterial cells and an overproduction of reactive oxygen species (ROS). It's crucial to note that, while this study did not specifically involve resistant strains, its primary focus remains on enhancing the overall antimicrobial activity of gentamicin. The research aims to contribute to addressing the global challenge of antimicrobial resistance, recognizing the urgent need for effective strategies to combat this critical issue. The findings, particularly the observed synergy between ZnO NPs and GEN, hold significant implications for repositioning the first-line antibiotic GEN.
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AIMS: To phytosynthesize silver nanoparticles (AgNPs) and determine their antibacterial and antibiofilm capacity against gram-positive and gram-negative bacterial strains. METHODS AND RESULTS: AgNPs were synthesized using Bothriochloa laguroides aqueous extract as reducing and stabilizing agent. After characterization, a phytochemical screening to the extract and the AgNPs was performed. Antibacterial activity, inhibition and eradication of biofilms against Staphylococcus aureus and Yersinia enterocolitica strains were tested. Spherical AgNPs with an average size of 8 nm were obtained. Tannins, flavonoids, carbohydrates, proanthocyanidins, anthocyanins and saponins were identified in aqueous extract; meanwhile, only carbohydrates were identified in AgNPs. The MIC and MBC were determined at pmol L-1 levels for all tested strains. Furthermore, AgNPs inhibited more than 90% of biofilms formation and eradicated more than 80% of mature biofilms at concentrations higher than MIC. CONCLUSIONS: The AgNPs obtained in this study inhibited planktonic and sessile growth, and eradicated mature biofilms of pathogenic bacterial strains at very low concentrations. SIGNIFICANCE AND IMPACT OF STUDY: The current study showed the promising potential of AgNPs as antibiofilm agents opening the way for the future development of a new class of antibacterial products.
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Antibacterianos , Nanopartículas del Metal , Poaceae/química , Plata , Staphylococcus aureus , Yersinia enterocolitica , Antocianinas , Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/farmacología , Plata/farmacología , Staphylococcus aureus/efectos de los fármacos , Yersinia enterocolitica/efectos de los fármacosRESUMEN
Antimicrobial drug resistance is a serious challenge in clinical settings worldwide, with biofilm formation having been associated with this problem. In the present study, the synergism of oligostyrylbenzene (OSB) compounds in combination with amphotericin B (AmB) against Candida tropicalis biofilms was investigated. In addition, the toxicity in human blood cells was determined. Synergistic combinations of OSBs and AmB were evaluated to consider future effects of OSBs in vivo. The checkerboard microdilution method was used to study the interactions of one anionic (1) and two cationic (2 and 3) OSBs with AmB. We investigated the effects of OSBs on reactive oxygen species (ROS) and the levels of the reactive nitrogen intermediates (RNIs). The cellular stress affected biofilm growth through an accumulation of ROS and RNI, at synergistic concentrations of OSBs and AmB. Furthermore, significant surface topography differences were noted upon treatment with the OSB 2/AmB combination, using confocal laser scanning microscopy in conjunction with the image analysis software COMSTAT. The results revealed a low toxicity to leukocytes and red blood cells at synergistic combinations of cationic OSBs with AmB. These findings demonstrated the antibiofilm effects of OSBs and the synergism of AmB with cationic OSBs against biofilms of C. tropicalis for the first time.
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Anfotericina B , Candida tropicalis , Anfotericina B/farmacología , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Biopelículas , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
The capacity of different naphthoquinones to inhibit and eradicate Yersinia enterocolitica biofilm was investigated and possible mechanisms of action were evaluated. Inhibition of biofilm formation and cell viability, quorum sensing (QS) inhibition and oxidative stress generation of 23 naphthoquinones were assayed against Yersinia enterocolitica. The best anti-biofilm agents at 100 µmol l-1 were compounds 3, 11 and 13, which showed biofilm inhibition higher than 75%. Compound 3 was the most effective against biofilm forming capacity of Y. enterocolitica WAP 314 with a minimum biofilm inhibitory concentration (MBIC) of 25 µmol l-1; while against Y. enterocolitica CLC001, the lowest MBIC was 6.1 µmol l-1 for compound 11. Acyl-homoserine lactones production was decreased with compound 13. We showed that the oxidative stress influence biofilm growth, by means of ROS and RNI increment. All treatments increased ROS and RNI values in the biofilm of both strains; while in planktonic cells, the increase was lesser. Additionally, Y. enterocolitica WAP 314 biofilm treated with compounds 11 and 13 showed above 80% of SOD consumption. In Y. enterocolitica CLC001 biofilm all compounds induced above 90% of SOD consumption. The SOD activity was higher in biofilm than in planktonic cells. In conclusion, this is the first study to demonstrate that naphthoquinones are able to inhibit biofilm formation of Y. enterocolitica without critical disturbing its planktonic growth. Naphthoquinones as anti-biofilm agents might potentially be useful in the treatment of biofilm-associated infections in the future.
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Biopelículas/crecimiento & desarrollo , Naftoquinonas/farmacología , Yersinia enterocolitica/fisiología , Acil-Butirolactonas/metabolismo , Biopelículas/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana , Estructura Molecular , Naftoquinonas/química , Estrés Oxidativo , Yersinia enterocolitica/efectos de los fármacosRESUMEN
As sessile cells of fungal biofilms are at least 500-fold more resistant to antifungal drugs than their planktonic counterparts, there is a requirement for new antifungal agents. Olygostyrylbenzenes (OSBs) are the first generation of poly(phenylene)vinylene dendrimers with a gram-positive antibacterial activity. Thus, this study aimed to investigate the antifungal activity of four OSBs (1, 2, 3, and 4) on planktonic cells and biofilms of Candida tropicalis. The minimum inhibitory concentration (MIC) for the planktonic population and the sessile minimum inhibitory concentrations (SMIC) were determined. Biofilm eradication was studied by crystal violet stain and light microscopy (LM), and confocal laser scanning microscopy (CLSM) was also utilized in conjunction with the image analysis software COMSTAT. Although all the OSBs studied had antifungal activity, the cationic OSBs were more effective than the anionic ones. A significant reduction of biofilms was observed at MIC and supraMIC50 (50 times higher than MIC) for compound 2, and at supraMIC50 with compound 3. Alterations in surface topography and the three-dimensional architecture of the biofilms were evident with LM and CLSM. The LM analysis revealed that the C. tropicalis strain produced a striking biofilm with oval blastospores, pseudohyphae, and true hyphae. CLSM images showed that a decrease occurred in the thickness of the mature biofilms treated with the OSBs at the most effective concentration for each one. The results obtained by microscopy were supported by those of the COMSTAT program. Our results revealed an antibiofilm activity, with compound 2 being a potential candidate for the treatment of C. tropicalis infections. LAY SUMMARY: This study aimed to investigate the antifungal activity of four OSBs (1, 2, 3, and 4) on planktonic cells and biofilms of Candida tropicalis. Our results revealed an antibiofilm activity, with compound 2 being a potential candidate for the treatment of C. tropicalis infections.
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Antifúngicos/farmacología , Derivados del Benceno/farmacología , Biopelículas/efectos de los fármacos , Candida tropicalis/efectos de los fármacos , Antifúngicos/aislamiento & purificación , Derivados del Benceno/química , Biopelículas/crecimiento & desarrollo , Candidiasis/tratamiento farmacológico , Descubrimiento de Drogas , Pruebas de Sensibilidad Microbiana , Microscopía ConfocalRESUMEN
BACKGROUND: Persister cells (PCs) make up a small fraction of microbial population, can survive lethal concentrations of antimicrobial agents. In recent years, Candida tropicalis has emerged as being a frequent fungal agent of medical devices subject to biofilm infections. However, PCs are still poorly understood. OBJECTIVES: This study aimed to investigate the relation of PCs on the redox status in C. tropicalis biofilms exposed to high doses of Amphotericin B (AmB), and alterations in surface topography and the architecture of biofilms. METHODS: We used an experimental model of two different C. tropicalis biofilms exposed to AmB at supra minimum inhibitory concentration (SMIC80), and the intra- and extracellular reactive oxygen species (iROS and eROS), reactive nitrogen species (RNS) and oxidative stress response were studied. Light microscopy (LM) and confocal laser scanning microscopy (CLSM) were also used in conjunction with the image analysis software COMSTAT. RESULTS: We demonstrated that biofilms derived from the PC fraction (B2) showed a higher capacity to respond to the stress generated upon AmB treatment, compared with biofilms obtained from planktonic cells. In B2, a lower ROS and RNS accumulation was observed in concordance with higher activation of the antioxidant systems, resulting in an oxidative imbalance of a smaller magnitude compared to B1. LM analysis revealed that the AmB treatment provoked a marked decrease of biomass, showing a loss of cellular aggrupation, with the presence of mostly yeast cells. Moreover, significant structural changes in the biofilm architecture were noted between both biofilms by CLSM-COMSTAT analysis. For B1, the quantitative parameters bio-volume, average micro-colony volume, surface to bio-volume ratio and surface coverage showed reductions upon AmB treatment, whereas increases were observed in roughness coefficient and average diffusion distance. In addition, untreated B2 was substantially smaller than B1, with less biomass and thickness values. The analysis of the above-mentioned parameters also showed changes in B2 upon AmB exposure. CONCLUSION: To our knowledge, this is the first study that has attempted to correlate PCs of Candida biofilms with alterations in the prooxidant-antioxidant balance and the architecture of the biofilms. The finding of regular and PCs with different cellular stress status may help to solve the puzzle of biofilm resistance, with redox imbalance possibly being an important factor.
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The development of environmental friendly new procedures for the synthesis of metallic nanoparticles is one of the main objectives of nanotechnology. Plants, algae, fungi and bacteria for the production of nanomaterials are viable alternatives due to their low cost, the absence of toxic waste production and their highly energy efficiency. It is also known that biosynthesized silver nanoparticles (AgNPs) show higher biocompatibility compared to the chemically-synthesized ones. In previous results, biosynthesized AgNPs were obtained from the supernatant of Pseudomonas aeruginosa, and they showed a bigger antimicrobial activity against different bacterial species compared to the chemically-synthesized ones. The aim of this work was to analyze the capping of biosynthesized AgNPs using techniques such as transmission electron microscopy (TEM), infrared spectroscopy (IR), and protein identification through mass spectrometry (MS) in order to identify the compounds responsible for their formation, stability and biocompatibility. The TEM images showed that AgNPs were surrounded by an irregular coverage. The IR spectrum showed that this coverage was composed of carbohydrates and/or proteins. Different proteins were identified in the capping associated to biosynthesized AgNPs. Some proteins seem to be important for their formation (Alkyl hydroperoxide reductase and Azurin) and stabilization (Outer membrane protein OprG and Glycine zipper 2â¯Tâ¯M domain-containing protein). The proteins identified with the capability to interact with some biomolecules can be responsible for the biocompatibility and may be responsible for the bigger antimicrobial activity than AgNPs have previously shown. These results are pioneers in the identification of proteins in the capping of biosynthesized AgNPs.
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Proteínas Bacterianas/química , Materiales Biocompatibles/metabolismo , Nanopartículas del Metal/química , Pseudomonas aeruginosa/química , Plata/metabolismo , Proteínas Bacterianas/metabolismo , Materiales Biocompatibles/química , Tamaño de la Partícula , Pseudomonas aeruginosa/metabolismo , Plata/química , Propiedades de SuperficieRESUMEN
The aim of this study was to design a nanocarrier system for inhalation delivery of rifampicin (RIF) in combination with ascorbic acid (ASC), namely constituted of sodium alginate coated with chitosan and Tween 80 (RIF/ASC NPs) as a platform for the treatment of pulmonary tuberculosis infection. A Box-Behnken experimental design and response surface methodology (RSM) were applied to elucidate and evaluate the effects of several factors on the nanoparticle properties. On the other hand, it was found that RIF/ASC NPs were less cytotoxic than the free RIF, showing a significantly improved activity against nine clinical strains of Mycobacterium tuberculosis (M. tb) in comparison with the free drug. RIF/ASC NPs had an average particle size of 324.0 ± 40.7 nm, a polydispersity index of 0.226 ± 0.030, and a zeta potential of - 28.52 ± 0.47 mV and the surface was hydrophilic. The addition of sucrose (1% w/v) to the nanosuspension resulted in the formation of a solid pellet easily redispersible after lyophilization. RIF/ASC NPs were found to be stable at different physiological pH values. In summary, findings of this work highlight the potential of the RIF/ASC NP-based formulation development herein to deliver RIF in combination with ASC through pulmonary route by exploring a non-invasive route of administration of this antibiotic, increasing the local drug concentrations in lung tissues, the primary infection site, as well as reducing the risk of systemic toxicity and hence improving the patient compliance.
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Alginatos/administración & dosificación , Ácido Ascórbico/administración & dosificación , Quitosano/administración & dosificación , Mycobacterium tuberculosis/efectos de los fármacos , Nanopartículas/administración & dosificación , Rifampin/administración & dosificación , Alginatos/química , Alginatos/farmacocinética , Animales , Antibióticos Antituberculosos/administración & dosificación , Antibióticos Antituberculosos/química , Antibióticos Antituberculosos/farmacocinética , Ácido Ascórbico/química , Ácido Ascórbico/farmacocinética , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Quitosano/química , Quitosano/farmacocinética , Chlorocebus aethiops , Relación Dosis-Respuesta a Droga , Portadores de Fármacos/administración & dosificación , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Humanos , Mycobacterium tuberculosis/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Tamaño de la Partícula , Rifampin/química , Rifampin/farmacocinética , Células VeroRESUMEN
BACKGROUND: The use of microorganisms for the synthesis of nanoparticles (NPs) is relatively new in basic research and technology areas. PURPOSE: This work was conducted to optimized the biosynthesis of iron NPs intra- and extracellular by Escherichia coli or Pseudomonas aeruginosa and to evaluate their anticoagulant activity. STUDY DESIGN/METHODS: The structures and properties of the iron NPs were investigated by Ultraviolet-visible (UV-vis) spectroscopy, Zeta potential, Dynamic light scattering (DLS), Field emission scanning electron microscope (FESEM)/ Energy dispersive X-ray (EDX) and transmission electron microscopy (TEM). Anticoagulant activity was determined by conducting trials of Thrombin Time (TT), Activated Partial Prothrombin Time (APTT) and Prothrombin Time (PT). RESULTS: UV-vis spectrum of the aqueous medium containing iron NPs showed a peak at 275 nm. The forming of iron NPs was confirmed by FESEM/ EDX, and TEM. The morphology was spherical shapes mostly with low polydispersity and the average particle diameter was 23 ± 1 nm. Iron NPs showed anticoagulant activity by the activation of extrinsic pathway. CONCLUSION: The eco-friendly process of biosynthesis of iron NPs employing prokaryotic microorganisms presents a good anticoagulant activity. This could be explored as promising candidates for a variety of biomedical and pharmaceutical applications.
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Anticoagulantes/química , Hierro/química , Nanopartículas del Metal/química , Anticoagulantes/metabolismo , Escherichia coli/química , Escherichia coli/metabolismo , Humanos , Tamaño de la Partícula , Pseudomonas aeruginosa/química , Pseudomonas aeruginosa/metabolismoRESUMEN
The photophysical, photoinduced pro-oxidant and antibacterial properties in vitro of the natural occurring parietin (PTN; 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthraquinone) were evaluated. PTN was extracted from the lichen identified as Teloschistes flavicans (Sw.) Norm. (Telochistaceae). Results indicate that in chloroform solution, PTN presents spectroscopic features corresponding to an excited-state intramolecular proton-transfer (ESIPT) state with partial keto-enol tautomerization. In argon-saturated solutions, the singlet excited state is poorly fluorescent (ΦF = 0.03), decaying by efficient intersystem crossing to an excited triplet state 3PTN*, as detected by laser-flash photolysis experiments. In the presence of triplet molecular oxygen, the 3PTN* was fully quenched producing singlet molecular oxygen (1O2) with a quantum yield of 0.69. In addition, in buffer solutions, PTN has the ability to also generate a superoxide radical anion (O2Ë-) in a human leukocyte model and its production was enhanced under UVA-Vis irradiation. Finally, the in vitro antibacterial capability of PTN in the dark and under UVA-Vis illumination was compared in microbial cultures of both Gram positive and negative bacteria. As a result, PTN showed promising photo-induced antibacterial activity through the efficient photosensitized generation of both 1O2 and O2Ë- species. Thus, we have demonstrated that PTN, an efficient photo-screening pigment in lichens, is also a good photosensitizer in solution with promising applications in antibacterial photodynamic therapy.
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Emodina/análogos & derivados , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacología , Animales , Antibacterianos/química , Antibacterianos/farmacología , Supervivencia Celular/efectos de los fármacos , Chlorocebus aethiops , Emodina/química , Emodina/aislamiento & purificación , Emodina/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/efectos de la radiación , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/efectos de la radiación , Humanos , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Leucocitos/efectos de la radiación , Líquenes/química , Líquenes/metabolismo , Luz , Pruebas de Sensibilidad Microbiana , Fármacos Fotosensibilizantes/aislamiento & purificación , Oxígeno Singlete/química , Oxígeno Singlete/metabolismo , Espectrofotometría Ultravioleta , Superóxidos/química , Superóxidos/metabolismo , Rayos Ultravioleta , Células VeroRESUMEN
The development and characterization of a novel, gel-type material based on a dendronized polymer (DP) loaded with ciprofloxacin (CIP), and the evaluation of its possible use for controlled drug release, are presented in this work. DP showed biocompatible and non-toxic behaviors in cultured cells, both of which are considered optimal properties for the design of a final material for biomedical applications. These results were encouraging for the use of the polymer loaded with CIP (as a drug model), under gel form, in the development of a new controlled-release system to be evaluated for topical administration. First, DP-CIP ionic complexes were obtained by an acid-base reaction using the high density of carboxylic acid groups of the DP and the amine groups of the CIP. The complexes obtained in the solid state were broadly characterized using FTIR spectroscopy, XRP diffraction, DSC-TG analysis and optical microscopy techniques. Gels based on the DP-CIP complexes were easily prepared and presented excellent mechanical behaviors. In addition, optimal properties for application on mucosal membranes and skin were achieved due to their high biocompatibility and acute skin non-irritation. Slow and sustained release of CIP toward simulated physiological fluids was observed in the assays (in vitro), attributed to ion exchange phenomenon and to the drug reservoir effect. An in vitro bacterial growth inhibition assay showed significant CIP activity, corresponding to 38 and 58% of that exhibited by a CIP hydrochloride solution at similar CIP concentrations, against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. However, CIP delivery was appropriate, both in terms of magnitude and velocity to allow for a bactericidal effect. In conclusion, the final product showed promising behavior, which could be exploited for the treatment of topical and mucosal opportunistic infections in human or veterinary applications.
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Antibacterianos/química , Ciprofloxacina/química , Dendrímeros/química , Portadores de Fármacos/química , Geles/química , Polímeros/química , Animales , Antibacterianos/metabolismo , Antibacterianos/farmacología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ciprofloxacina/metabolismo , Ciprofloxacina/farmacología , Portadores de Fármacos/toxicidad , Liberación de Fármacos , Humanos , Concentración de Iones de Hidrógeno , Iones/química , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/efectos de los fármacos , Conejos , Reología , Piel/efectos de los fármacos , Espectroscopía Infrarroja por Transformada de Fourier , Staphylococcus aureus/efectos de los fármacosRESUMEN
Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones. This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using a Pseudomonas aeruginosa strain from a reference culture collection. A greenish culture supernatant of P. aeruginosa incubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs. Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Proteus mirabilis, Acinetobacter baumannii, Escherichia coli, P. aeruginosa, and Klebsiella pneumonia. Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains. This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistant S. aureus, A. baumannii, and E. coli. In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host.
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The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. The main aim of this work was to establish the potential of the synthetic α-diimine chromium(III) and ruthenium(II) complexes (where the α-diimine ligands are bpy = 2,2-bipyridine, phen = 1,10-phenanthroline, and dppz = dipyrido[3,2-a:2',3'-c]-phenazine) like [Cr(phen)3](3+), [Cr(phen)2(dppz)](3+), [Ru(phen)3](2+), and [Ru(bpy)3](2+) as antibacterial agents by generating oxidative stress. The [Cr(phen)3](3+) and [Cr(phen)2(dppz)](3+) complexes showed activity against Gram positive and Gram negative bacteria with minimum inhibitory concentrations (MICs) ranging from 0.125 µg/mL to 1 µg/mL, while [Ru(phen)3](2+) and [Ru(bpy)3](2+) do not exhibit antimicrobial activity against the two bacterial genera studied at the concentration range used. When ciprofloxacin was combined with [Cr(phen)3](3+) for the inhibition of Staphylococcus aureus and Escherichia coli, an important synergistic effect was observed, FIC 0.066 for S. aureus and FIC 0.064 for E. coli. The work described here shows that chromium(III) complexes are bactericidal for S. aureus and E. coli. Our results indicate that α -diimine chromium(III) complexes may be interesting to open new paths for metallodrug chemotherapy against different bacterial genera since some of these complexes have been found to exhibit remarkable antibacterial activities.
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Cromo/farmacología , Escherichia coli/efectos de los fármacos , Rutenio/farmacología , Staphylococcus aureus/efectos de los fármacos , Antiinfecciosos/farmacología , Cromo/química , Pruebas de Sensibilidad Microbiana , Compuestos Organometálicos/química , Estrés Oxidativo/efectos de los fármacos , Fenantrolinas/química , Rutenio/química , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiologíaRESUMEN
The present study was undertaken to explore the interaction of ciprofloxacin and chloramphenicol with bacterial membranes in a sensitive and in a resistant strains of Staphylococcus aureus by using 1-anilino-8-naphthalene sulfonate (ANS). The binding of this probe to the cell membrane depends on the surface potential, which modulates the binding constant to the membrane. We observed that these antibiotics interacted with the bilayer, thus affecting the electrostatic surface potential. Alterations caused by antibiotics on the surface of the bacteria were accompanied by a reduction in the number of binding sites and an increase in the ANS dissociation constant in the sensitive strain, whereas in the ciprofloxacin-resistant strain no significant changes were detected. The changes seen in the electrostatic surface potential generated in the membrane of S. aureus by the antibiotics provide new aspects concerning their action on the bacterial cell.
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Cloranfenicol/farmacología , Ciprofloxacina/farmacología , Membrana Dobles de Lípidos/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/fisiología , Naftalenosulfonatos de Anilina/metabolismo , Pruebas de Sensibilidad MicrobianaRESUMEN
Proteins and lipids maybe important targets of oxidation and this may alter their functions. We evaluated whether ceftazidima (CAZ), piperacillin (PIP), chloramphenicol (CMP), and ciprofloxacin (CIP) could oxidize the macromolecules in the three bacterial genera Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. There was an increase in lipid peroxidation observed in these three species. However, this was lower in the Gram negative bacteria than in S. aureus. A reduction of the carbonyl residue in S. aureus with ciprofloxacin was observed whereas in Gram negative bacteria the antibiotics increased the carbonyl residue with respect to the control. Although the strains suffered a rise in advanced oxidation protein products (AOPP) in the presence of ciprofloxacin, the S. aureus strain had a smaller increase of AOPP than the other strains. The results described in this article provide data about the susceptibility of the three bacterial genera to the oxidative stress induced by the antibiotics studied.
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Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/metabolismo , Sustancias Macromoleculares/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Bacterianas/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Carbonilación Proteica/efectos de los fármacosRESUMEN
The aim of this study was to evaluate the in vitro effect of chloramphenicol in order to determine its potential toxic effects on human neutrophils, by using assays of reactive oxygen species (ROS) determination, nitrite measurement and antioxidant systems. Chloramphenicol enabled the oxidative stress response of neutrophils and increased the ROS production at 2, 4, 8 and 16 microg/ml, while ROS generation decreased at high concentrations (32 microg/ml). The nitroblue tetrazolium assay shows that neutrophils incubated with chloramphenicol increased the intracellular ROS, with the extracellular production rising with a corresponding increase in antibiotic concentration. Enzymatic activities--superoxide dismutase, catalase and diaphorase enzymes--increased after chloramphenicol treatment, while the glutathione level decreased in neutrophils incubated with antibiotic. The results obtained in the present work suggest that the study of susceptibility to oxidative stress in neutrophils before chloramphenicol treatment could be adequate for in vitro toxicity screening.
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Antibacterianos/toxicidad , Cloranfenicol/toxicidad , Neutrófilos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Antioxidantes/metabolismo , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Neutrófilos/enzimología , Neutrófilos/metabolismo , Nitritos/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Staphylococcus aureus and Escherichia coli sensitive to chloramphenicol incubated with this antibiotic suffered oxidative stress with increase of anion superoxide (O2-). This reactive species of oxygen was detected by chemiluminescence with lucigenin. S. aureus, E. coli, and Enterococcus faecalis sensitive to ciprofloxacin exhibited oxidative stress when they were incubated with this antibiotic while resistant strains did not show stimuli of O2-. Other bacteria investigated was Pseudomonas aeruginosa, strains sensitive to ceftazidime and piperacillin presented oxidative stress in presence of these antibiotics while resistant strains were not stressed. Higher antibiotic concentration was necessary to augment O2- in P. aeruginosa biofilm than in suspension, moreover old biofilms were resistant to oxidative stress caused by antibiotics. A ceftazidime-sensitive mutant of P. aeruginosa, coming from a resistant strain, exhibited higher production of O2- than wild type in presence of this antibiotic. There was relation between antibiotic susceptibility and production of oxidative stress.