Evaluation of behavior, growth, and swarming formation of Escherichia coli and Staphylococcus aureus in culture medium modified with silver nanoparticles

2020 ◽  
Vol 149 ◽  
pp. 104480
Author(s):  
Lucio Assis Araujo Neto ◽  
Tatiane Melo Pereira ◽  
Luciano Paulino Silva
2018 ◽  
Vol 15 (29) ◽  
pp. 282-291
Author(s):  
D. GANCHALA ◽  
J. L. GU.CORONADO ◽  
E. JARA ◽  
L. MENESES ◽  
E. GRANDA ◽  
...  

Currently, resistance to antibiotics has become a problem for the treatment of infectious diseases. In this study, silver nanoparticles were synthesized using the aqueous extract of Palo santo (Burseragraveolens), for its biocide action, in order to determine its antimicrobial effect on Escherichia coli and Staphylococcus aureus. Different concentrations of nanoparticles (100 until1000 ppm) were evaluated at contact times of 1, 2, 5 and 10 minutes for 1500 and 15000 CFU/mL. Additionally, to determine effectiveness, disc diffusion tests using various concentrations of nanoparticles (500-1000 ppm) were performed on S.aureus and K. pneumoniae. According to the results of antimicrobial effect for E.coli, the effectiveness of nanoparticles can be established at all contact times for 1500 CFU from 800 ppm and for 15000 CFU from 400 ppm. With S.aureus, total inhibition was showed from 800 ppm in 1500 CFU at 5 minutes of contact and between 500-1000 ppm with 15000 CFU at minute one. S. aureus and K.pneumoniae tests showed sensitivity with nanoparticles. The average of susceptibility for S.aureus had the lowest inhibition between 500-600 ppm and the highest at 700-800 ppm. The average susceptibility for K. pneumoniae is more constant in terms of inhibition at 600-1000 ppm. This study demonstrated the antimicrobial effect of silver nanoparticles synthesized under the specified conditions.


2018 ◽  
Vol 9 (2) ◽  
pp. 025019 ◽  
Author(s):  
Xuan Hoa Vu ◽  
Thi Thanh Tra Duong ◽  
Thi Thu Ha Pham ◽  
Dinh Kha Trinh ◽  
Xuan Huong Nguyen ◽  
...  

2021 ◽  
Vol 15 (4) ◽  
pp. 493-499
Author(s):  
Galyna Zozulya ◽  
◽  
Orest Kuntyi ◽  
Roman Mnykh ◽  
Martyn Sozanskyi ◽  
...  

“Green” synthesis of silver nanoparticles (AgNPs) by a galvanic replacement (GR) on magnesium in solutions of sodium polyacrylate (NaPA) under ultrasound (42 kHz) is reported. The mechanism of combined action of GR and ultrasound on the formation of nanoparticles is proposed. Synthesized solutions of AgNPs are characterized by an absorption maximum at 410 nm, the value of which does not depend on the concentrations of precursors (AgNO3 and NaPA) and the duration of the process. The dimensions of nanoparticles that have a spherical shape do not exceed 30 nm. With increasing concentration of surfactant, there is a tendency to decrease in size. The rate of synthesis of AgNPs increases almost in proportion to the concentration of AgNO3 in the solution, while the effect of NaPA concentration is negligible. The synthesized nanoparticles efficiently demonstrated a bactericide effect on Escherichia coli and Staphylococcus aureus.


2020 ◽  
Vol 10 (3) ◽  
pp. 316-329
Author(s):  
Fateme Mirzajani ◽  
Amin Hamidi

Introduction: In this project, the growth and volatile metabolites profiles of Escherichia coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical, nanoparticle and ultra-highly diluted compounds. Materials & Methods: The treatments were done for 12000 life cycles using silver nanoparticles (AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later. Also, with the continuous usage of these materials, no more bacterial growth was observed. Results: The most important compounds produced by E. coli are Acetophenone, Octyl acetate, Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol. The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde, 2-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were common and produced by both organisms. Conclusion: Based on the origin of the produced volatiles, main volatiles percentage of untreated sample is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).


2019 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Ariyetti Ariyetti ◽  
Muhammad Nasir ◽  
Safni Safni ◽  
Syukri Darajat

<p><em>Metil merah merupakan salah satu zat warna golongan azo yang sering digunakan dalam industri dan laboratorium. Penggunaan metil merah dapat menimbulkan efek terhadap kesehatan dan lingkungan. Oleh sebab itu dilakukan metode fotodegradasi dengan menggunakan semikonduktor dan radiasi sinar tampak. Semikonduktor yang digunakan yaitu berbahan dasar tembaga sulfat hidrat dan perak nitrat. Prekusor tembaga sulfat hidrat dibuat dari pengolahan limbah logam tembaga hasil pemotongan tembaga yang ada di bengkel Lembaga Ilmu Pengetahuan Indonesia (LIPI) Bandung. Bahan semikonduktor juga memiliki kemampuan dalam menghambat pertumbuhan bakteri. Hasil optimum yang didapatkan dalam proses fotodegradasi dan antibakteri merupakan gabungan antara kedua prekusor tembaga sulfat hidrat dan perak nitrat dengan bantuan penyinaran. Kemampuan dalam menghambat pertumbuhan bakteri didapatkan persentase kematian 100 % untuk masing-masing bakteri, yaitu Escherichia coli dan Staphylococcus aureus. Aktifitas fotokatalitiknya dengan konsentrasi semikonduktor 10 ppm untuk mendegradasi zat warna metil merah 5 ppm, selama 23 jam, dimana persentase degradasi yang didapatkan dengan penyinaran lebih tinggi dibandingkan dengan tanpa penyinaran. Pengaruh pH larutan terhadap degradasi metil merah yaitu optimum pada pH 12 (basa).</em></p><p><em><br /></em></p><p><em>Methyl red is one of the azo group dyes that is often used in industry and laboratories. The use of methyl red can have an effect on health and the environment. Therefore photodegradation method is done by using semiconductor and visible light radiation. The semiconductor used is based on copper sulfate hydrate and silver nitrate. The copper sulphate hydrate precursor is made from the processing of copper-cut copper metal waste in the workshop of the Indonesian Institute of Sciences (LIPI) in Bandung. Semiconductor materials also have the ability to inhibit bacterial growth. The optimum results obtained in the photodegradation and antibacterial process are a combination of both copper sulfate hydrate precursor and silver nitrate with the help of irradiation. The ability to inhibit bacterial growth obtained 100% mortality for each bacterium, namely Escherichia coli and Staphylococcus aureus. Photocatalytic activity with 10 ppm semiconductor concentration to degrade methyl red dye 5 ppm, for 23 hours, where the percentage of degradation obtained by irradiation is higher than without irradiation. The effect of pH of the solution on the degradation of methyl red is optimum at pH 12 (base).</em></p>


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