Biological activity of synthesized silver nanoparticles on S. aureus and P. aeruginosa (original) (raw)
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EVALUATION OF ANTIBACTERIAL BEHAVIOUR OF SILVER NANOPARTICLES.
It is well known that Silver nanoparticles has great affinity against many pathogenic microbes i.e silver nanoparticles possess good antimicrobial properties against many bacteria and fungi. Staphylococcus aureus is one of the most pathogenic bacteria causing infections on skin, respiratory tract, not only this it also cause life threatening diseases such as pneumonia, meningitis etc. Inhibitory effect of silver nanoparticles against staphylococcus aureus gram positive bacteria was evaluated by in-vitro disc diffusion method.The bacterial strains were treated with silver nanoparticle discs at varying concentrations. The antibacterial activity was evaluated by measuring zone of inhibition around antimicrobial disc.
World Journal of Microbiology and …, 2011
Antimicrobial activity of silver nanoparticles is gaining importance due its broad spectrum of targets in cell compared to conventional antimicrobial agents. In this context, a UV photo-reduction method was used for the synthesis and the nanoparticles were characterized by UV-Visible spectroscopy, transmission electron microscopy, atomic force microscopy and thermogravimetric analysis techniques. The antibacterial activity of the synthesized silver nanoparticles was evaluated both in liquid and solid growth media employing various susceptibility assays on Pseudomonas aeruginosa, a ubiquitous bacterium. The dose dependent growth suppression by nanoparticles was studied with well diffusion method. By broth dilution method, the minimum inhibitory concentration (MIC) was found to be 2 lg/ml. It was observed that the bactericidal effect depends both on nanoparticle concentration and number of bacteria present. In our study, we could demonstrate the complete antibiofilm activity of silver nanoparticles at a concentration as low as 1 lg/ml. Our observations substantiated the association of reactive oxygen species and cell membrane damage in the antibacterial mechanism of silver nanoparticles. Our findings suggested that these nanoparticles can be exploited towards the development of potential antibacterial coatings for various biomedical and environmental applications.
Antibacterial effect of silver nanoparticles in <em>Pseudomonas aeruginosa</em>
Nanotechnology, Science and Applications, 2017
Pseudomonas aeruginosa has great intrinsic antimicrobial resistance limiting the number of effective antibiotics. Thus, other antimicrobial agents such as silver nanoparticles (AgNPs) are considered potential agents to help manage and prevent infections. AgNPs can be used in several applications against bacteria resistant to common antibiotics or even multiresistant bacteria such as P. aeruginosa. This study assessed the antimicrobial activity of commercial 10 nm AgNPs on two hospital strains of P. aeruginosa resistant to a large number of antibiotics and a reference strain from a culture collection. All strains were susceptible to 5 µg/ mL nanoparticles solution. Reference strains INCQS 0230 and P.a.1 were sensitive to AgNPs at concentrations of 1.25 and 0.156 µg/mL, respectively; however, this was not observed for hospital strain P.a.2, which was more resistant to all antibiotics and AgNPs tested. Cytotoxicity evaluation indicated that AgNPs, up to a concentration of 2.5 µg/mL, are very safe for all cell lines tested. At 5.0 µg/mL, AgNPs had a discrete cytotoxic effect on tumor cells HeLa and HepG2. Results showed the potential of using AgNPs as an alternative to conventional antimicrobial agents that are currently used, and a perspective for application of nanosilver with antibiotics to enhance antimicrobial activity.
2021
ABSTRACTAntibacterial activity of biosynthesized silver nanoparticles was studied using the macrobroth dilution technique. The silver nanoparticles was significantly active (p > 0.05) against the test organisms at an extract concentration of 75 µg/ml. Concentrations ≤ 50 µg/ml were not as effective as the colony forming units at this concentration, 1.61 × 106 for methicillin-resistant Staphylococcus aureus and concentrations ≤ 25 µg/ml 1.45 × 106 for Pseudomonas aeruginosa respectively, were about the same range as the colony forming units of the controls. The silver nanoparticles inhibited Methicillin-Resistant S. aureus more (MIC of 75 µg/ml and MBC of 100 µg/ml) than they inhibited P. aeruginosa (both MIC and MBC was 100 µg/ml). The LD50 of the synthesized silver nanoparticles after oral administration was seen to be greater than 5000 mg/kg body weight and is therefore thought to be safe. This study supports the use of silver nanoparticles as therapeutic agents.
Mycopathologia, 2009
Conventionally physical and chemical methods are used for the biosynthesis of silver nanoparticles. Biological methods of nanoparticles synthesis are cost effective, easily scaled up and environmental friendly. A green synthesis of silver nanoparticles has been achieved using environmentally acceptable plant extract. It was observed that Moringa oleifera Lam leaf extract can reduce silver ions into silver nanoparticles at room temperature. The synthesized nanoparticles have been characterized by the UV–visible spectroscopy, high resolution transmission electron microscopy. Further, the antibacterial activity of silver nanoparticles was evaluated by well diffusion method and it was found that the biogenic silver nanoparticles have antibacterial activity against Pantoea agglomerans (27mm) followed by Ralstonia solanacearum , Erwinia amylovora and Pseudomonas lachrymans (19.66 mm, 16.66 mm and 13 mm, respectively) and the lowest for Agrobacterium tumefaciens and no effect on Erwinia ca...
Advancements in Life Sciences, 2017
Background: Over the last two decades infectious agents have become more dangerous, most especially in developing countries, due to their ability to develop resistance against orthodox medicines. Many in these countries are suffering from the debilitating effects of these pathogens without any remedies in sight. The recent researches in nanoparticles derived from medicinal plants seem to be yielding positive results. Methods: We carried out synthesis of silver nanoparticles from AgNO 3 and using Hyaluronic acid as a stabilizing agent to avoid aggregation in green synthesis from Ziziphus spinachristi and Garcinia kola . Transmission electron microscopy (TEM) was used to determine particle size and shape. Disc diffusion technique was used to study the susceptibility patterns of the particles on the test organisms- Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Staphylococcus aureus . Result: The nanoparticles exhibited very high activity against the pathogens at very l...
Backgrounds: Emergence of bacterial resistance to several antibiotic are causing serious problem in health care. Even the broad-spectrum bactericidal effect of ionic form of silver sometimes found to be ineffective; few cases are reported to ascertain the incident of silver resistance. The purpose of the study was to examine the potency and mechanistic bactericidal actions of Silver Nano particles (AgNPs) on E. coli as model gram negative bacteria. Methods: Antibacterial activity of nano-sized silver particle was investigated against E. coli, Minimum Inhibitory Concentration (MIC) of AgNPs was determined following National Committee for Clinical Laboratory Standard (NCCLS) guideline, in Mueller- Hinton (MH) broth supplemented with different concentration of AgNPs. Growth pattern of bacteria at the MIC of AgNPs was studied and the mechanism of bactericidal action of AgNPs was observed by Transmission Electron Microscopy (TEM). Results: The antimicrobial activity AgNPs were investigated in liquid system and the results are showing that AgNPs were attached on the surface of the bacterial cell membrane; probably by the surface charge attraction followed by formation pits which destroy the integrity of the bacterial cell wall, resulting in death of the bacterial cells. Conclusions: AgNPs produce strong bactericidal action event at very low concentrations because of their high surface to volume ratio and remains effective for a longer duration. So it could be an effective therapy for open wounds if applied topically.
Trends in Pharmaceutical Sciences, 2017
The bactericidal efficiency of various positively charged silver nanoparticles has been extensively evaluated in literature, but there is no report on efficacy of various positive charged silver nanoparticles. The goal of this study is to evaluate the role of different positive electrical charge at the surface of silver nanoparticles on antibacterial activity against a panel of microorganisms and their biofilm activities and their cytotoxicity. Four different silver nanoparticles were synthesized by different methods, providing four different electrical surface charges (two ionic liquids (imidazolium and pyridinium) with 12 and 18 alkyl chain length) namely C12Im, C12Py, C18Im and C18Py, respectively. The antibacterial activity of these nanoparticles was tested against gram-positive (i.e., Staphylococcus aureus, Bacillus subtilis), gramnegative (i.e., Escherichia coli and Salmonella typhi) bacteria and Candida albicans as fungi. Disc diffusion and micro-dilution tests were used to evaluate the bactericidal activity of the nanoparticles according to CLSI methods. Also primary cytotoxicity assay of nanosilvers was assessed by MTT test. According to the obtained results, C12Py showed the highest bactericidal activity against all microorganisms tested. C18Im had the least and the C12Im had intermediate antibacterial activity. The most resistant bacteria were Escherichia coli. Different positive surface charge of silver nanoparticles was a significant factor affecting their bactericidal activity. Although the nanoparticles capped with pyridinium and 12 alkyl chains showed the highest level of effectiveness against the organisms tested, the silver nanoparticles capped with imidazolium and 12 alkyl chains were also potent against most bacterial species. Cytotoxicity of the silver nanoparticles was negligible.
Synthesis of nanosized particles with antibacterial properties is of great interest in the development of new pharmaceutical products. Silver nanoparticles (Ag NPs) are known to have inhibitory and bactericidal effects. In this article we present the synthesis of Ag NPs prepared by chemical reduction from aqueous solutions of silver nitrate, containing a mixture of hydrazine hydrate and sodium citrate as reductants and sodium dodecyl sulfate as a stabilizer. The results of the characterization of the Ag NPs show agglomerates of grains with a narrow size distribution (from 40 to 60 nm), whereas the radii of the individual particles are between 10 and 20 nm. Finally, the antibacterial activity was measured by the Kirby-Bauer method. The results showed reasonable bactericidal activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The standard dilution micromethod, determining the minimum inhibitory concentration leading to inhibition of bacterial growth, is still under way. Preliminary results have been obtained.
In Vitro Antibacterial Activity of Biological-Derived Silver Nanoparticles: Preliminary Data
Veterinary Sciences, 2020
Silver nanoparticles (AgNPs) are promising alternatives to antibiotics. The aims of this study were to produce AgNPs using two biological methods and determine their antibacterial activity against Pseudomonas aeruginosa and Staphylococcus pseudintermedius. AgNPs were biosynthesized from an infusion of Curcuma longa (turmeric) and the culture supernatant of E. coli. Characterization was achieved by ultraviolet-visible spectroscopy and by Transmission Electron Microscopy (TEM). The antibacterial properties of NPs from C. longa (ClAgNPs) and E. coli (EcAgNPs), alone and in combination with carbenicillin and ampicillin, were investigated through the Kirby-Bauer disk diffusion assay and the minimum inhibitory concentration (MIC). Dimensions of NPs ranged from 11.107 ± 2.705 nm (ClAgNPs) to 27.282 ± 2.68 nm (EcAgNPs). Kirby-Bauer and MIC assays showed great antibacterial abilities for both NPs alone and in combination with antibiotics. EcAgNPs alone showed the most powerful antibacterial ...