scholarly journals Synthesis of Silk Silver Nanoparticles form Silkworm Cocoons and Their Antibacterial Activity on Methicillin Resistant Staphylococcus aureus (MRSA) and Escherichia coli

Author(s):  
Harinatha Reddy A ◽  
Venkatappa B
Biomédica ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 11 ◽  
Author(s):  
Mónica Tatiana Herrera ◽  
Jhon Jhamilton Artunduaga ◽  
Claudia Cristina Ortiz ◽  
Rodrigo Gonzalo Torres

Introducción. Las nanopartículas poliméricas constituyen una herramienta nanotecnológica que podría ayudar a combatir los microorganismos patógenos que han desarrollado resistencia a los antibióticos convencionales.Objetivo. Sintetizar nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina, y determinar su actividad antibacteriana frente a Escherichia coli O157:H7 y Staphylococcus aureus resistente a la meticilina (SARM).Materiales y métodos. Las nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina se sintetizaron utilizando el método de emulsión y evaporación de solvente. Se caracterizaron mediante dispersión de luz en modo dinámico, electroforesis Doppler con láser y microscopía electrónica de barrido (S-TEM). Se evaluó la actividad antibacteriana in vitro de las nanopartículas de ácido poliláctico con ofloxacina contra E. coli O157:H7 y nanopartículas de ácido poliláctico con vancomicina contra SARM, mediante el método de microdilución en caldo.Resultados. Se obtuvieron nanopartículas poliméricas con tamaños inferiores a 379 nm y carga superficial positiva de hasta 21 mV. Las nanopartículas cargadas con ofloxacina presentaron una concentración inhibitoria mínima (CIM50) de 0,001 μg/ml frente a E. coli O157:H7, valor 40 veces menor que la concentración de antibiótico libre necesaria para lograr el mismo efecto (CIM50=0,04 μg/ml). Para SARM, las nanopartículas mejoraron la potencia farmacológica in vitro de la vancomicina alexhibir una MIC50 de 0,005 μg/ml, comparada con la de 0,5 μg/ml del antibiótico libre.Conclusiones. Se mejoró el efecto antibacteriano de la ofloxacina y la vancomicina incorporadas en la matriz polimérica de ácido poliláctico. Las nanopartículas poliméricas constituirían una alternativa para el control de cepas bacterianas de interés en salud pública.


2021 ◽  
Author(s):  
Ifeyomi Wilfred Olobayotan ◽  
Bukola Catherine Akin-Osanaiye ◽  
Olukemi A. Onuh

Antibacterial 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 x 106 for methicillin-resistant Staphylococcus aureus and concentrations ≤ 25 µg/ml 1.45 x 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. KEYWORDS: Nanoparticles, Biosynthesis, Inhibition, Therapeutic agents, Macroboth Technique


2021 ◽  
Vol 16 (3) ◽  
pp. 1934578X2110024
Author(s):  
Bala Namata Abba ◽  
Amadou Tidjani Ilagouma ◽  
Issoufou Amadou ◽  
Abderrahmane Romane

In the present study, the chemical composition, antioxidant and antibacterial activities of the essential oil obtained by hydrodistillation of the aerial parts of Englerastrum gracillimum Th. C. E. Fries growing in Niger were investigated. Gas chromatography-mass spectrometry (GC–MS) analysis of the essential oil resulted in the identification of 42 compounds representing 97.9% of the total oil constituents. The major compounds of the essential oil were: α-humulene (30.5%), followed by cubenol (19.8%), γ-muurolene (14.0%), ( E)-β-caryophyllene (5.8%), β-gurjunene (5.2%), and curzerene (4.9%). The antioxidant activity of the essential oil was determined by using the free radical-scavenging activity (2,2 diphenyl-1-picrylhydrazyl: DPPH˙) and ferric reducing antioxidant power assays. The essential oil showed good antioxidant potential with both methods. The antibacterial activity was evaluated against multi-resistant Acinetobacter baumannii P1483, extended-spectrum β-lactamase (ESBL) -Escherichia coli Bu8566, Salmonella spp. H1548, Proteus mirabilis Bu190 , Enterobacter cloacae Bu147, Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), methicillin-resistant Staphylococcus aureus P1123, Enterococcus faecium H3434, and Staphylococcus aureus (ATCC 25923) using the agar disc diffusion and microdilution methods. The essential oil exhibited good antibacterial activity. The highest antibacterial effect was observed against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus P1123 with minimal inhibitory concentration (MIC) values of 0.03 mg/mL and 0.06 mg/mL, respectively. These data are of scientific importance for the valorization of aromatic and medicinal plants of Niger, especially E. gracillimum. This study reports for the first time the antioxidant and antibacterial activities of this essential oil.


2021 ◽  
Author(s):  
Thu Ha Bui ◽  
Ngoc Dai Nghia Tran ◽  
Phung Anh Nguyen ◽  
Nhat Linh Duong ◽  
Van Minh Nguyen ◽  
...  

Abstract A cost-effective and green technique was performed for the synthesis of silver nanoparticles (AgNPs) from a plant resource using Citrus maxima peel (CMP) extract as a reducing agent. The formation of AgNPs was confirmed by UV-Vis Spectroscopy at the wavelength range of 400−500 nm. The optimized conditions for the AgNPs synthesis using CMP extract as a reducing agent were determined. At these conditions, the X-ray diffraction (XRD) and the high-resolution transmission electron microscopy (HRTEM) results revealed the face-centered cubic structure of AgNPs had a highly crystalline with the particle size in a range of 10−20 nm. The Fourier transform infrared spectroscopy (FT-IR) demonstrated the presence of flavonoid, terpenoid, phenolic, and glycosides in phytochemical compositions of CMP extract which can act as the reducing agents for AgNPs formation. The antibacterial effect of the AgNPs was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA) by implementing the minimum inhibitory concentration (MIC), minimum batericidal concentration (MBC), and the zone of inhibition tests. The AgNPs exhibited effective antibacterial activity against bacteria with an average diameter of inhibition zones of 11.7 mm, the MIC of 8.27 µg/mL, and the MBC of the 16.54 µg/mL.


Author(s):  
Manipriya B ◽  
Tasneem Banu ◽  
Prem Kumar L ◽  
Kalyani M

 Objective: To determine the virulence factors-biofilm, nuclease and phosphatase production in Staphylococcus aureus isolates. To determine the effect of silver nano particles and antibiotics on MRSA by MIC determination and kirby baeur method respectively and finally to compare antibacterial activity of silver nano particles and antibiotics.Methods: In the present study, we explore the antibacterial activity of silver nanoparticles (Ag-NPs) dispersion (10 nm) against reference strain and clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). We evaluated the antibacterial activity of Ag-NPs against MRSA isolated from patients in Saveetha Medical College and Hospital, a tertiary care centre in Chennai, Tamil Nadu. The bactericidal activity of different concentrations of Ag-NPs (200, 100, 50, 25, 12.5, 6.25, 3.125, and 1.5625 μg/ml) was tested by determining MIC using microbroth dilution and MBC by agar dilution methods.. In addition, the virulence factors phosphatase, nuclease, and biofilm production were tested.Result: The values of minimal inhibitory concentration and minimal bactericidal concentration of Ag-NPs against all clinical isolates of MRSA and a single of S. aureus were found in the range of 12.5–50 μg/ml and 12.5–25 μg/ml, respectively, indicating very good bactericidal activity. Ag-NPs with the highest concentration showed almost no growth for up to 16 h representing a bactericidal effect at this concentration. Effect was proportional to dose since 50.0 μg/ml was the most effective dose since the bacterial population did not recover and 12.5 μg/ml was the least effective. All the MRSA isolates were positive for the virulence factors.Conclusion: The study result suggests that Ag-NPs could be used as an effective alternative antibacterial agent.


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