scholarly journals Photocatalytic effect of led radiation (405 nm) and new Al2O3 3D-nanocomposites on the growth of Staphylococcus aureus

Author(s):  
Anna V. Svetlakova ◽  
◽  
Elena S. Tuchina ◽  

The progressive growth of bacterial resistance to antibiotic drugs requires the creation of highly efficient nanomaterials. Aluminum oxide is a stable non-toxic semiconductor material; however, the photocatalytic properties of its modifications in relation to microorganisms are not well understood. In this study, we used new 3D composites of aluminum oxyhydroxide (Al2O3 × nH2O) in three modifications (γ, α and θ), which are a mesh of 150 nm nanofibrils. The assessment of the photocatalytic antibacterial properties of the composites was carried out on the museum strain S. aureus 209 P. It was shown that, in combination with violet LED radiation (405 nm, 17 mW/cm2), the composites under study significantly suppress bacterial growth (from 65 to 89%), with the sample containing γ-Al2O3 showing the best result.

2021 ◽  
Vol 9 (1) ◽  
pp. 8-14
Author(s):  
Janrigo Klaumegio Mere ◽  
Maria Bintang ◽  
Mega Safithri

Bacterial resistance is a serious problem that until now still has become a global problem. The search for new antibacterial compounds is needed to overcome this problem. Syzygium cumini (L.) Skeels is a plant known to contain bioactive compounds that can be used as an antibacterial agent. This study aims to explore the leaves of this plant as an antibacterial against Escherichia coli pBR322 resistant bacteria. Based on the antibacterial test results, extracts and leaf fractions of this plant can inhibit bacterial growth. Ethyl acetate fraction at a concentration of 800 ppm showed strong antibacterial activity with an inhibition zone diameter of 10.36±0.02 mm followed by ethanol extract and other fractions, namely 8.43±0.01 mm (ethanol extract), 7.24±0.01 mm (water fraction), and 1.45±0.01 mm (n-hexane fraction). The results of spectrophotometric MIC determination also showed inhibition against bacterial growth, which was marked by a decrease in the absorbance value at the lowest antibacterial concentration of 600 ppm from 0.454 to 0.070 at wavenumber 600 nm after 24 hours of incubation. The decrease in the absorbance value indicated that the antibacterial properties of the plant leaves at this concentration were effective in inhibiting bacterial growth.


2021 ◽  
pp. 147-152
Author(s):  
Laila Ben Ramadan ◽  
Abdurzag Zwawi ◽  
Mohamed Salem ◽  
Abdurzag Auzi ◽  
Ahmed El Marghani

Bacterial resistance develops due to overuse of antibiotics in addition to the adverse effects of these chemicals. This urges the scientists to exchange these antibiotics with alternatives from natural products. The study aimed to evaluate the antimicrobial efficiency of Arum cyrenicum Hruby against a number of medically important pathogenic bacteria. A. cyreniacum corms extracted with petroleum ether, chloroform and methanol, and tested for antimicrobial activity against Escherichia coli BTC3, Salmonella typhi BTC10, Pseudomonas aeruginosa BTC4, and Staphylococcus aureus BTC15. A considerable bactericidal efficiency of petroleum ether extract of A. cyrenaicum corms were specifically against gram-positive bacteria, Staphylococcus aureus BTC15 at (100 mg/ml) petroleum ether and bacteriostatic at (50 mg/ml) of petroleum Ether extract. Whereas, the methanolic extract of A. cyrenaicum corms had bactricidal effect against gram-negative bacteria, Pseudomonas auregenosa BTC4 at (100mg/ml) of methanolic extract. Herby our results indicate that petroleum ether and methanolic extracts of A. cyrenaicum possess significant antibacterial properties. Keywords: Arum cyrenicum, Efficiency, Antibacterial


Author(s):  
A. O. Daniels ◽  
J. K. Fadairo ◽  
A. O. Fashoyin

The use of biologically synthesized nanoparticles has been an area of research interest in recent times. Due to the high rate of bacterial resistance to antibiotics, there is a need to search for a more potent alternative to ineffective antibiotics. This study aims to evaluate the antibacterial effects of silver nanoparticles synthesized by Bacillus subtilis against Pseudomonas aeruginosa and Staphylococcus aureus. Silver nanoparticles were obtained by dissolving 0.842 gram of AgNO3 silver nitrate into 100ml of B. subtilis in Mueller Hinton broth. The antibacterial susceptibility of the nanoparticles formed was carried out using standard methods. Comparative antibacterial test was also carried out using standard antibiotics The multiple antibiotic resistance index were also determined. The zones of inhibition were 29 and 12 mm against Staphylococcus aureus and Pseudomonas aeruginosa respectively after 8 hrs of nanoparticle synthesis. The antibiotic susceptibility test using standard antibiotics revealed that S. aureus was sensitive to only Erythromycin and ofloxacin with a zone of inhibition of 15mm and 9mm respectively while P. aeruginosa was sensitive only to ofloxacin. The Multiple resistance index (MARi) shows P aeruginosa to have MARi of 0.9 while S, aureus has MARi of 0.82. The result indicated that B. subtilis nanoparticles presented better antibacterial properties than standard antibiotic and can be explored as a candidate for drug production to fight bacterial resistance to antibiotics.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Donald Mabhiza ◽  
Tariro Chitemerere ◽  
Stanley Mukanganyama

The development of new antibiotics from new chemical entities is becoming more and more expensive, time-consuming, and compounded by emerging strains that are drug resistant. Alkaloids are plant secondary metabolites which have been shown to have potent pharmacological activities. The effect of alkaloids from Callistemon citrinus and Vernonia adoensis leaves on bacterial growth and efflux pump activity was evaluated on Staphylococcus aureus and Pseudomonas aeruginosa. At a concentration of 1.67 mg/mL, the alkaloids inhibited bacterial growth with comparable effects to ampicillin, a standard antibiotic. The alkaloids from C. citrinus were the most potent against S. aureus with an MIC of 0.0025 mg/mL and MBC of 0.835 mg/mL. It was shown that effects on P. aeruginosa by both plant alkaloids were bacteriostatic. P. aeruginosa was most susceptible to drug efflux pump inhibition by C. citrinus alkaloids which caused an accumulation of Rhodamine 6G of 121% compared to the control. Thus, C. citrinus alkaloids showed antibacterial activity as well as inhibiting ATP-dependent transport of compounds across the cell membrane. These alkaloids may serve as potential courses of compounds that can act as lead compounds for the development of plant-based antibacterials and/or their adjunct compounds.


2021 ◽  
Vol 21 ◽  
Author(s):  
Ana Carolina Justino de Araújo ◽  
Priscilla Ramos Freitas ◽  
Cristina Rodrigues dos Santos Barbosa ◽  
Débora Feitosa Muniz ◽  
Jaime Jaime Ribeiro-Filho ◽  
...  

Aims: This study aimed to investigate the potential of limonene as an efflux pump (EP) inhibitor in Staphylococcus aureus strains RN-4220 and IS-58, which carry EPs for erythromycin (MrsA) and tetracycline (TetK), respectively. Background: The evolution of bacterial resistance mechanisms over time has impaired the action of most classes of antibiotics. Staphylococcus aureus is a notable bacterium, with high pathogenic potential and demonstrated resistance to conventional antibiotics. Considering the importance of discovering novel compounds to combat antibiotic resistance, our group previously demonstrated the antibacterial properties of limonene, a compound present in the essential oils of several plant species. Objective: This study aimed to investigate the potential of limonene as an efflux pump (EP) inhibitor in Staphylococcus aureus strains RN-4220 and IS-58, which carry EPs for erythromycin (MrsA) and tetracycline (TetK), respectively. Method: The minimum inhibitory concentrations (MIC) of limonene and other efflux pump inhibitors were determined through the broth microdilution method. A reduction in the MIC of ethidium bromide was used as a parameter of EP inhibition. Result: While limonene was not shown to exhibit direct antibacterial effects against EP-carrying strains, in association with ethidium bromide and antibiotics, this compound demonstrated enhanced antibacterial activity, indicating the inhibition of the MrsA and TetK pumps. Conclusion: In conclusion, this pioneering study demonstrated the effectiveness of limonene as an EP inhibitor in S. aureus strains RN-4220 and IS-58. Nevertheless, further studies are required to characterize the molecular mechanisms associated with limonene-mediated EP inhibition.


2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Hussein A Kadhum ◽  
Thualfakar H Hasan2

The study involved the selection of two isolates from Bacillus subtilis to investigate their inhibitory activity against some bacterial pathogens. B sub-bacteria were found to have a broad spectrum against test bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. They were about 23-30 mm and less against Klebsiella sp. The sensitivity of some antibodies was tested on the test samples. The results showed that the inhibitory ability of bacterial growth in the test samples using B. subtilis extract was more effective than the antibiotics used.


2020 ◽  
Vol 2 (2) ◽  
pp. 61-68
Author(s):  
Agnina Listya Anggraini ◽  
Ratih Dewi Dwiyanti ◽  
Anny Thuraidah

Infection is a disease caused by the presence of pathogenic microbes, including Staphylococcus aureus and Escherichia coli. Garlic (Allium sativum L.) has chemical contents such as allicin, alkaloids, flavonoids, saponins, tannins, and steroids, which can function as an antibacterial against Staphylococcus aureus and Escherichia coli. This study aims to determine the antibacterial properties of garlic extract powder against Staphylococcus aureus and Escherichia coli. This research is the initial stage of the development of herbal medicines to treat Staphylococcus aureus and Escherichia coli infections. The antibacterial activity test was carried out by the liquid dilution method. The concentrations used were 30 mg/mL, 40 mg/mL, 50 mg/mL, 60 mg/mL and 70 mg/mL. The results showed that the Minimum Inhibitory Concentration (MIC) against Staphylococcus aureus and Escherichia coli was 40 mg/mL and 50 mg / mL. Minimum Bactericidal Concentration (MBC) results for Staphylococcus aureus and Escherichia coli are 50 mg/mL and 70 mg/mL. Based on the Simple Linear Regression test, the R2 value of Staphylococcus aureus and Escherichia coli is 0.545 and 0.785, so it can be concluded that there is an effect of garlic extract powder on the growth of Staphylococcus aureus and Escherichia coli by 54.5% and 78.5%. Garlic (Allium sativum L.) extract powder has potential as herbal medicine against bacterial infections but requires further research to determine its effect in vivo.


2020 ◽  
Vol 16 ◽  
Author(s):  
Nihar Ranjan Panda ◽  
Dojalisa Sahu

Background: Metal oxide nanomaterial such as; ZnO shows novel structural, optical, electrical and antibacterial properties due to wide band gap (3.37 eV) and high excitonic binding energy (60 meV). Probing these inherent properties of nanosized ZnO with different morphology has generated new interest among researchers Objective: To investigate the size dependent functional attributes, ZnO nanorods were prepared by hydrothermal method and the photocatalytic (PC) efficiency was studied. The photoluminescence (PL) property of ZnO nanorods was also studied by recording the emission spectrum under photo-excitation. These nanorods (NRs) were coated on cotton fabric to study the effectiveness of these NRs in defending and inhibiting the growth of different bacteria Methods: The crystallographic structure and morphology of the ZnO samples were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopic (FESEM) measurements. PL measurement at room temperature was undertaken by exciting the sample with light of wavelength 350 nm. The PC property of ZnO NRs was studied in degrading organic dyes like methylene blue. Bacteria like Staphylococcus aureus, Escherichia coli and Bacillus subtilis were cultured and the inhibition of growth of these bacteria was studied by the application of ZnO. To enhance the microbe defence mechanism of fabric, we coated these NRs on fabric test samples and investigated the bacterial growth on it. Results: XRD and FESEM studies reveal the dimension of the synthesized products in nano range. These nanorods are of high density and surface roughness as per the FESEM study. PL measurement shows the presence of strong UV emission at 382 nm with defect emissions in the blue-green region opening up the path for ZnO to be used in fabrication of optoelectronic devices. PC study reveals that 89% degradation of methylene blue (MB) dye is achievable in 180 min using these ZnO catalysts. The anti-bacterial study shows that the minimum inhibitory concentration (MIC) of ZnO nanorods coated on the fabric against S. aureus is found to be 3.5 mg/ml which is the minimum as compared to E. coli (7.5 mg/ml) and B. subtilis (5.5 mg/ml). The study further enunciates that fabric coated with ZnO samples exhibited considerably high inhibition activity toward S. aureus. Conclusion: The study shows that ZnO NRs can be effectively used for fabrication of UV-LASER/LED. Photocatalytic efficiency of ZnO will be useful for degradation of organic dyes controlling environment pollution. It further enunciates that fabric coated with ZnO samples exhibited considerably high inhibition activity toward S. aureus (skin bacteria) which will be helpful in defending microbes if used in surgical cotton bandages


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>


Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Atanu Naskar ◽  
Sohee Lee ◽  
Kwang-sun Kim

Antibiotic therapy is the gold standard for bacterial infections treatment. However, the rapid increase in multidrug-resistant (MDR) bacterial infections and its recent use for secondary bacterial infections in many COVID-19 patients has considerably weakened its treatment efficacy. These shortcomings motivated researchers to develop new antibacterial materials, such as nanoparticle-based antibacterial platform with the ability to increase the chances of killing MDR strains and prevent their drug resistance. Herein, we report a new black phosphorus (BP)-based non-damaging near-infrared light-responsive platform conjugated with ZnO and Au nanoparticles as a synergistic antibacterial agent against Staphylococcus aureus species. First, BP nanosheets containing Au nanoparticles were assembled in situ with the ZnO nanoparticles prepared by a low-temperature solution synthesis method. Subsequently, the antibacterial activities of the resulting Au–ZnO–BP nanocomposite against the non-resistant, methicillin-resistant, and erythromycin-resistant S. aureus species were determined, after its photothermal efficacy was assessed. The synthesized nanocomposite exhibited excellent anti-S. aureus activity and good photothermal characteristics. The non-resistant S. aureus species did not produce drug-resistant bacteria after the treatment of multiple consecutive passages under the pressure of the proposed nanoantibiotic, but rapidly developed resistance to erythromycin. This work clearly demonstrates the excellent photothermal antibacterial properties of Au–ZnO–BP nanocomposite against the MDR S. aureus species.


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