scholarly journals Microwave-Hydrothermal Rapid Synthesis of Cellulose/Ag Nanocomposites and Their Antibacterial Activity

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Lian-Hua Fu ◽  
Qing-Long Gao ◽  
Chao Qi ◽  
Ming-Guo Ma ◽  
Jun-Feng Li

Silver-based antimicrobial nanomaterials are considered as the most promising antibacterial agents owing to their outstanding antimicrobial efficacy and their relatively low toxicity to human beings. In this work, we report on a facile and environment-friendly microwave-hydrothermal method to prepare cellulose/Ag nanocomposites using hemicellulose as the reductant. The influences of the microwave-hydrothermal heating time and temperature, as well as the hemicellulose concentration on the formation of cellulose nanocomposites, were investigated in detail. Experimental results indicated that the hemicellulose was an effective reductant for silver ions, with higher temperature and longer heating time favoring the formation of silver with higher crystallinity and mass content in the nanocomposites. Moreover, the antimicrobial properties of the as-prepared cellulose/Ag nanocomposites were explored using Gram-positive S. aureus ATCC 6538 and Gram-negative E. coli HB 101 by both disc diffusion method and agar dilution method, and the nanocomposites showed excellent antibacterial activity. These results demonstrate that the as-prepared cellulose/Ag nanocomposites, as a kind of antibacterial material, are promising for applications in a wide range of biomedical fields.

2020 ◽  
Vol 8 (10) ◽  
pp. 4600-4605
Author(s):  
Parween Bano ◽  
K. Shankar Rao ◽  
Sakhitha K. S ◽  
Nikita Rajpurohit

Knowledge of microorganisms was well stablished in Ayurveda in terms of krimi since Vedic period and have told that the organisms were invisible, scattered and present everywhere in which some are harmful or harmless to human beings. In Samhita clear cut description of invisible krimi is found and also said that they are causes various diseases like Jawar, Kushtha considered as contagious disease by Accharya Sushruta. Number of Ayurvedic formulation possess krimighna (antimicrobial) properties. Therefore, need of study to evaluate antimicrobial property of Ayurvedic formulations due to resistance of antibiotic which is challenge for modern medical science. Sheetamshu Rasa (SR) is one of the unique herbomineral formu-lation explained in text Basavarajiyam under Sannipataja Jwara Rogadhikara and also it has many indica-tions. Four samples of SR were prepared according to textual reference and slight modification in leviga-tion media & ratio of ingredients. Antimicrobial study was done in different concentrations in DMSO, against three bacteria Klebsiella pneumonia, Pseudomonas aeruginosa & Staphylococcus aureus produc-ing fever as a symptom by Agar well diffusion method and Ciprofloxacin (5 μg/ml) as antibacterial stand-ards. Result shows that SR samples had antibacterial activity moderate to high. SR1 and SR2 showed the best result in higher concentration than the other two samples (ZI= 11mm and AI= 0.92) on Klebsiela pneumonia. Trikatu and levigation media have no special significance in antibacterial activity.


2019 ◽  
Vol 65 (2) ◽  
pp. 99-102 ◽  
Author(s):  
Yu.V. Butina ◽  
T.V. Kudayarova ◽  
E.A. Danilova ◽  
M.K. Islyaikin

The work is devoted to predicting and studying biological properties of N-substituted analogs of 3,5-diamino-1,2,4-thiadiazole, which, in their turn, include in the composition of many drugs that exhibit a wide range of pharmacological actions. For searching of new alternative drugs with an antibacterial activity, but lacking resistance of microorganism strains to them, a computer screening of 2N-alkyl-substituted 5-amino-3-imino-1,2,4-thiadiazolines previously synthesized by us was carried out. The prediction of the spectrum of biological activity, as well as the determination of the probable toxicity of these compounds, was performed using the freely available computer programs PASS, Anti-Bac-Pred, and GUSAR. The study of the antibacterial activity in vitro against gram-positive (Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis) and gram-negative (Escherichia coli, Pseudomonas aeruginosae) bacterial strains was performed by the disco-diffusion method. Experimental data roughly correspond to the predictions.


2015 ◽  
Vol 9 (02) ◽  
pp. 149-156 ◽  
Author(s):  
Sintayehu Fekadu ◽  
Yared Merid ◽  
Hunachew Beyene ◽  
Wondu Teshome ◽  
Solomon Gebre-Selassie

Introduction: Large quantities of antimicrobials are used in hospitals for patient care and disinfection. Antibiotics are partially metabolized and residual quantities reach hospital wastewater, exposing bacteria to a wide range of biocides that could act as selective pressure for the development of resistance. Methodology: A cross-sectional study was conducted between December 2010 and February 2011 on hospital wastewater. A total of 24 composite samples were collected on a weekly basis for bacteriological analysis and susceptibility testing. Indicator organisms and pathogenic and potentially pathogenic bacteria were found and isolated on selective bacteriologic media. Disinfectant activity was evaluated by use-dilution, and minimum inhibitory concentration (MIC) was determined by the agar dilution method. Similarly, antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method. Results: Pathogenic (Salmonella, Shigella, and S. aureus) and potentially pathogenic (E. coli) bacteria were detected from effluents of both hospitals. Dilution demonstrated tincture iodine to be the most effective agent, followed by sodium hypochlorite; the least active was 70% ethanol. MIC for ethanol against S. aureus and Gram-negative rods from Yirgalem Hospital (YAH) showed 4 and 3.5 log reduction, respectively. Salmonella isolates from YAH effluent were resistant to ceftriaxone, tetracycline, and doxycycline. Isolates from Hawassa University Referral Hospital (HURH) effluent were resistant to the above three antibiotics as well as gentamycin. Conclusions: Hospital effluents tested contained antibiotic-resistant bacteria, which are released into receiving water bodies, resulting in a threat to public health.


Author(s):  
Dr. Vibha Bhardwaj

The antibacterial effect of Prosopis cineraria leaves was evaluated on multidrug resistant (MDR) strains of Bacillus subtilis (ATCC 6633), E. coli (ATCC 8739), Salmonella enterica (ATCC 14028), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 27853). Powdered leaves of the tree were treated with methanol for the extraction. Crude methanol extracts of the leaves of P. cineraria was investigated for their antibacterial activity against a wide range of bacteria (both gram-positive and gram-negative) by agar well diffusion method. Ciprofloxacin was used as standard. The methanolic leaves extracts of P. cineraria showed a remarkable inhibition of the microorganisms. The potency shown by these extracts recommends their use against multidrug resistant microorganisms. The present study suggests that the methanol extract of the leaves of P. cineraria exhibited a potential antibacterial activity against the tested microorganisms and could be a potential source of new antimicrobial agents.


Author(s):  

Infectious diseases are the most common causes of morbidity and mortality in developing countries. Nowadays, medicinal plants play a major role in treatment of infectious diseases and they are easily available and more affordable as compared to synthetic compounds. The emerging trends of multidrug resistance among several groups of microorganisms against different classes of antibiotics led different researchers to develop efficient drugs from plant sources to counter multidrug resistant strains. This study investigated two different concentration of methanol extracts of stem bark of Prosopis cineraria to determine their efficacy against multidrug resistant microbes. Powdered barks of the tree were treated with methanol using hot extraction method. Crude methanol extracts of the bark of P. cineraria was investigated for their antibacterial activity against a wide range of bacteria (both gram-positive and gram-negative) by disc diffusion method. Ciprofloxacin was used as standard. Multidrug resistant (MDR) strains of Bacillus subtilis (ATCC 6633), E. coli (ATCC 8739), Salmonella enterica (ATCC 14028), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 27853) were used in the study. The methanolic bark extracts of P. cineraria showed a remarkable inhibition of the microorganisms. The potency shown by these extracts recommends their use against multidrug resistant microorganisms. The present study suggests that the methanol extract of the stem bark of P. cineraria exhibited a potential antibacterial activity against the tested microorganisms and could be a potential source of new antimicrobial agents.


2005 ◽  
Vol 60 (9-10) ◽  
pp. 686-692
Author(s):  
Ismail Kiran ◽  
Semra Ilhan ◽  
Tamer Akar ◽  
Lacine Tur ◽  
Erdinc Erol

Abstract The in vitro antibacterial and antifungal activities of demethoxyviridin and some synthetic analogues were evaluated by the agar diffusion method. The minimum inhibitory concentrations (MIC) of the active compounds were also determined by the agar dilution method. Demethoxyviridin (1) showed moderate antibacterial activity against most of the strains tested. 1α-Hydroxydemethoxyviridin (3) showed antibacterial activity and the most potent in vitro antifungal activity with MIC of 20 μg/ml (0.062 mm) against Aspergillus niger, A. fumigatus, A. flavus, A. parasiticus, Fusarium solani, F. graminarum, Geotrichum candidum whereas 5′-methylfuro-(4′,3′,2′-4,5,6)androst-5-ene-3,17-dione (7) exhibited very weak antifungal activity against Candida albicans only.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4383
Author(s):  
Barbara Lapinska ◽  
Aleksandra Szram ◽  
Beata Zarzycka ◽  
Janina Grzegorczyk ◽  
Louis Hardan ◽  
...  

Modifying the composition of dental restorative materials with antimicrobial agents might induce their antibacterial potential against cariogenic bacteria, e.g., S.mutans and L.acidophilus, as well as antifungal effect on C.albicans that are major oral pathogens. Essential oils (EOs) are widely known for antimicrobial activity and are successfully used in dental industry. The study aimed at evaluating antibacterial and antifungal activity of EOs and composite resin material (CR) modified with EO against oral pathogens. Ten EOs (i.e., anise, cinnamon, citronella, clove, geranium, lavender, limette, mint, rosemary thyme) were tested using agar diffusion method. Cinnamon and thyme EOs showed significantly highest antibacterial activity against S.mutans and L.acidophilus among all tested EOs. Anise and limette EOs showed no antibacterial activity against S.mutans. All tested EOs exhibited antifungal activity against C.albicans, whereas cinnamon EO showed significantly highest and limette EO significantly lowest activity. Next, 1, 2 or 5 µL of cinnamon EO was introduced into 2 g of CR and microbiologically tested. The modified CR showed higher antimicrobial activity in comparison to unmodified one. CR containing 2 µL of EO showed the best antimicrobial properties against S.mutans and C.albicans, while CR modified with 1 µL of EO showed the best antimicrobial properties against L.acidophilus.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Séverine Boisard ◽  
Anne-Marie Le Ray ◽  
Anne Landreau ◽  
Marie Kempf ◽  
Viviane Cassisa ◽  
...  

During this study, thein vitroantifungal and antibacterial activities of different extracts (aqueous and organic) obtained from a French propolis batch were evaluated. Antifungal activity was evaluated by broth microdilution on three pathogenic strains:Candida albicans, C. glabrata, andAspergillus fumigatus. Antibacterial activity was assayed using agar dilution method on 36 Gram-negative and Gram-positive strains includingStaphylococcus aureus. Organic extracts showed a significant antifungal activity againstC. albicansandC. glabrata(MIC80between 16 and 31 µg/mL) but only a weak activity towardsA. fumigatus(MIC80= 250 µg/mL). DCM based extracts exhibited a selective Gram-positive antibacterial activity, especially againstS. aureus(SA) and several of its methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains (MIC10030–97 µg/mL). A new and active derivative of catechin was also identified whereas a synergistic antimicrobial effect was noticed during this study.


2016 ◽  
Vol 10 (1) ◽  
pp. 211-221 ◽  
Author(s):  
Blessing Ike ◽  
Malachy C. Ugwu ◽  
Moses N. Ikegbunam ◽  
David Nwobodo ◽  
Chika Ejikeugwu ◽  
...  

Objectives:This study evaluated the prevalence, antibiogram and molecular features of CA-MRSA in Awka, Nigeria.Methods:Confirmation of MRSA was done by testing resistance to oxacillin (1µg), cloxacillin (5µg) and cefoxitin(30µg) on sterile Mueller Hinton agar supplemented with 4% sodium chloride. The MRSA strains were subjected to antimicrobial susceptibility testing using Kirby-Bauer disc diffusion method. Minimum inhibitory concentration was determined using agar dilution method. Penicillin binding protein 2a was detected through rapid latex agglutination assay while mecA gene was detected by polymerase chain reaction. A total of 142S. aureusisolates were obtained from 261 samples sourced from Staff, students and fomites of the Faculty of Pharmaceutical SciencesResult:The overall prevalence of MRSA was 22.6%. The carriage rate was higher in females (56.5%) than male (43.5%) and was highest in individuals of 20-30 years of age (57.65%). The MIC of the oxacillin sodium salt ranged from 4-32 μg/ml. The multi-antibiotic resistance indices show that 53.4% had Multiple Antibiotic Resistance Indexing (MARI) higher than 0.2. Penicillin binding protein 2a was detected in 8.4% of MRSA isolates, all from nasal carriage while mecA gene was detected in 5 of isolates.Conclusion:This study showed a very high prevalence of MRSA carriage among studied subjects.


EKOLOGIA ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 31-39
Author(s):  
Oom Komala ◽  
. Ismanto ◽  
Muhammad Alan Maulana

Streptococcus pyogenes is one of the pathogenic bacteria that causes pharyngitis. Natural treatment to overcome these problems is to use cardamom seeds. The purpose of this study was to test the antibacterial activity, determine the concentration of inhibitory zone and phytochemical compounds from  ethanol 96% extract of Java cardamom seeds (Amomum compactum Soland. Ex Maton) against Streptococcus pyogenes. The method is used   solid dilution and paper disc diffusion method. The solid dilution method is used for the Minimum Inhibitory Concentration (MIC) test with a concentration of 1.25%, 2.5%, 5% and 7.5% while the paper diffusion method is used for the Inhibition zone Diameter (IZD)  using five treatments namely three concentrations of ethanol 96% extract of Java cardamom seeds (7.5%, 10% and 12%), one positive control of amoxicillin 0.01 mg/mL and one negative control of sterile distilled water. IZD data were  analyzed using ANOVA with a confidence level of 95% and α = 0.05 and Duncan's further tests to determine differences between treatments. The results showed that the MIC  was at a concentration of 7.5% while for the IZD test which had the highest activity there was a concentration of 12% with an average inhibition diameter of 12.03 ± 0.14 mm. In addition, ethanol 96% extract of Java cardamom seeds contain alkaloids, flavonoids, terpenoids and tannins which function in antibacterial activity.


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