scholarly journals Pollution- induced community tolerance framework - disc diffusion method to assess the impact of silver nanoparticles in soils: Potential relevance for risk assessment

2022 ◽  
Vol 169 ◽  
pp. 104185
Author(s):  
Sara Peixoto ◽  
Jacinta M.M. Oliveira ◽  
Isabel Henriques ◽  
Rui G. Morgado ◽  
Amadeu M.V.M. Soares ◽  
...  
2018 ◽  
Vol 29 (2) ◽  
pp. 37-41
Author(s):  
M Iqbal Hossain ◽  
M Anwar Habib ◽  
Nazimuddin Ahmed

This quasi experimental study was designed to evaluate antibacterial activity of chemically synthesized silver nanoparticles (AgNPs) from silver nitrate (AgNO3) solutions on gram negative bacteria like E.Coli using disc diffusion method. Different concentrations of AgNPs, AgNO3 and reference drug ciprofloxacin were used to find out the antibacterial activity which revealed that AgNPs possessed significant antibacterial effect compared to AgNO3 solutions but relatively less antibacterial effect than that of ciprofloxacin. So chemical synthesis guided AgNPs may have some antibacterial effects.TAJ 2016; 29(2): 37-41


2012 ◽  
Vol 4 (4) ◽  
pp. 55-61 ◽  
Author(s):  
Sankaran MIRUNALINI ◽  
Vadivel ARULMOZHI ◽  
Krishnamoorthy DEEPALAKSHMI ◽  
Mani KRISHNAVENI

The process of biosynthesis of silver nanoparticles is a simple, cost effective and eco-friendly approach. Biosynthesis of silver nanoparticles using some commonly available edible mushroom extracts and their antimicrobial activity was demonstrated in the current study. The formation of silver nanoparticles was confirmed by UV, FTIR and SEM and antibacterial activity was tested using disc diffusion method. From the results it is confirmed the successful formation of silver nanoparticles using mushroom extracts; they performed their role as a reducing and capping agent and also exhibited a potent antibacterial activity against S. aureus (gram positive bacteria). Thus the biosynthesis of silver nanoparticles using edible mushroom extract will deserve to be a good candidate as an antibacterial agent.


2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
A. Arul Prakash ◽  
S. Balasubramanian ◽  
G. Gunasekaran ◽  
M. Prakash ◽  
P. Senthil Raja

In the present study, effort has been made to find the antimicrobial activity of haemolymph collected from freshwater crab, Paratelphusa hydrodromous. The haemolymph collected was tested for antimicrobial assay by disc diffusion method against clinical pathogens. Five bacterial species, namely, Escherichia coli, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and five fungal strains, namely and Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Rhizopus sp., and Mucor sp., were selected for the study. The result shows a strong response of haemolymph against the clinical pathogens which confirms the immune mechanism of the freshwater crab.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helal F. Hetta ◽  
Israa M. S. Al-Kadmy ◽  
Saba Saadoon Khazaal ◽  
Suhad Abbas ◽  
Ahmed Suhail ◽  
...  

AbstractWe aimed to isolate Acinetobacter baumannii (A. baumannii) from wound infections, determine their resistance and virulence profile, and assess the impact of Silver nanoparticles (AgNPs) on the bacterial growth, virulence and biofilm-related gene expression. AgNPs were synthesized and characterized using TEM, XRD and FTIR spectroscopy. A. baumannii (n = 200) were isolated and identified. Resistance pattern was determined and virulence genes (afa/draBC, cnf1, cnf2, csgA, cvaC, fimH, fyuA, ibeA, iutA, kpsMT II, PAI, papC, PapG II, III, sfa/focDE and traT) were screened using PCR. Biofilm formation was evaluated using Microtiter plate method. Then, the antimicrobial activity of AgNPs was evaluated by the well-diffusion method, growth kinetics and MIC determination. Inhibition of biofilm formation and the ability to disperse biofilms in exposure to AgNPs were evaluated. The effect of AgNPs on the expression of virulence and biofilm-related genes (bap, OmpA, abaI, csuA/B, A1S_2091, A1S_1510, A1S_0690, A1S_0114) were estimated using QRT-PCR. In vitro infection model for analyzing the antibacterial activity of AgNPs was done using a co-culture infection model of A. baumannii with human fibroblast skin cell line HFF-1 or Vero cell lines. A. baumannii had high level of resistance to antibiotics. Most of the isolates harbored the fimH, afa/draBC, cnf1, csgA and cnf2, and the majority of A. baumannii produced strong biofilms. AgNPs inhibited the growth of A. baumannii efficiently with MIC ranging from 4 to 25 µg/ml. A. baumannii showed a reduced growth rate in the presence of AgNPs. The inhibitory activity and the anti-biofilm activity of AgNPs were more pronounced against the weak biofilm producers. Moreover, AgNPs decreased the expression of kpsMII , afa/draBC,bap, OmpA, and csuA/B genes. The in vitro infection model revealed a significant antibacterial activity of AgNPs against extracellular and intracellular A. baumannii. AgNPs highly interrupted bacterial multiplication and biofilm formation. AgNPs downregulated the transcription level of important virulence and biofilm-related genes. Our findings provide an additional step towards understanding the mechanisms by which sliver nanoparticles interfere with the microbial spread and persistence.


2021 ◽  
Vol 37 (2) ◽  
pp. 54-64
Author(s):  
D.V. Barabash ◽  
I.A. Butorova

The possibility of using simple and available methods for analyzing deodorants/antiperspirants has been studied. The gravimetric method was shown to have acceptable metrological characteristics under repeatability conditions when evaluating antiperspirant activity. A decrease in the number of microorganisms (CFU) on the axilla skin was observed in a rinse test experiment 4 h and 8 h after the application of deodorants/antiperspirants. The microbial population data were inversely proportional to the antiperspirant activity values of the tested compositions. The sweat secretion reducing decreases the amount of nutrients required for microbial development, which makes it possible to use the rinse test to indirectly evaluate deodorant activity in research and development of personal care products. However, due to its laboriousness and the need for volunteers, the method cannot be recommended for large-scale testing. It was shown that the disc diffusion method (DDM) used to detect Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis cannot be applied to the assessment of the intrinsic antimicrobial activity of the tested cosmetic compositions. This indicates the necessity of additional studies to select test microorganisms typical for the armpit area. In addition, DDM is useful if the deodorant effect of the composition is created by the addition of low-volatile antibacterial compounds. Therefore, microbiological methods have limited applications and are not suitable for widespread use. deodorant action; antiperspirant action, gravimetry, disc diffusion method, rinse test; deodorant; antiperspirant; cosmetic; efficiency; consumer properties, functional properties This work was supported by MUCTR (project no. K-2020-007).


10.5219/1695 ◽  
2021 ◽  
Vol 15 ◽  
pp. 1112-1119
Author(s):  
Hana Ďúranová ◽  
Veronika Valková ◽  
Lucia Galovičová ◽  
Jana Štefániková ◽  
Miroslava Kačániová

Fungal food spoilage plays a key role in the deterioration of food products, and finding a suitable natural preservative can solve this problem. Therefore, antifungal activity of green mandarin (Citrus reticulata) essential oil (GMEO) in the vapor phase against the growth of Penicillium (P.) expansum and P. chrysogenum inoculated on wheat bread (in situ experiment) was investigated in the current research. The volatile compounds of the GMEO were analyzed by a gas chromatograph coupled to a mass spectrometer (GC–MS), and its antioxidant activity was determined by testing free radical-scavenging capacity (DPPH assay). Moreover, the disc diffusion method was used to analyze the antifungal activity of GMEO in in vitro conditions. The results demonstrate that the Citrus reticulata EO consisted of α-limonene as the most abundant component (71.5%), followed by γ-terpinene (13.9%), and β-pinene (3.5%), and it displayed the weak antioxidant activity with the value of inhibition 5.6 ±0.7%, which corresponds to 103.0 ±6.4 µg TEAC.mL-1. The findings from the GMEO antifungal activity determination revealed that values for the inhibition zone with disc diffusion method ranged from 0.00 ±0.00 (no antifungal effectiveness) to 5.67 ±0.58 mm (moderate antifungal activity). Finally, exposure of Penicillium strains growing on bread to GMEO in vapor phase led to the finding that 250 μL.L-1 of GMEO exhibited the lowest value for mycelial growth inhibition (MGI) of P. expansum (-51.37 ±3.01%) whose negative value reflects even supportive effect of the EO on the microscopic fungus growth. On the other hand, GMEO at this concentration (250 μL.L-1) resulted in the strongest inhibitory action (MGI: 54.15 ±1.15%) against growth of P. chrysogenum. Based on the findings it can be concluded that GMEO in the vapor phase is not an effective antifungal agent against the growth of P. expansum inoculated on bread; however, its antifungal potential manifested against P. chrysogenum suggests GMEO to be an appropriate alternative to the use of chemical inhibitors for bread preservation.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Somayeh Razmavar ◽  
Mahmood Ameen Abdulla ◽  
Salmah Binti Ismail ◽  
Pouya Hassandarvish

This study was based on screening antibacterial activity of the ethanol extract ofBaeckea frutescensL. against MRSA clinical isolates, analyzes the potential antibacterial compound, and assesses the cytotoxicity effect of the extract in tissue culture. Leaves ofBaeckea frutescensL. were shade dried, powdered, and extracted using solvent ethanol. Preliminary phytochemical screening of the crude extracts revealed the presence of alkaloids, flavonoids, steroids, terpenoids, phenols, and carbohydrates. The presence of these bioactive constituents is related to the antibacterial activity of the plant. Disc diffusion method revealed a high degree of activity against microorganisms. The results confirm thatBaeckea frutescensL. can be used as a source of drugs to fight infections caused by susceptible bacteria.


2017 ◽  
Vol 11 (2) ◽  
pp. 17-19
Author(s):  
Rahima Akter ◽  
Shikha Paul ◽  
Akhtarun Naher ◽  
Moshiur Rahman ◽  
Sharmin Sultana ◽  
...  

Nasal carriage of MRSA among hospital stuff act as a source of endogenous infection and becomes a source for hospital and community acquired infection. The study was conducted to determine the rate antibiotic resistance pattern of nasal carriage of MRSA among the hospital stuff of Sir Salimullah Medical College and Mitford Hospital, Dhaka. Pre moistened nasal swabs from hospital stuff (doctor, nurses, lab technicians and other helping stuff were obtained. These swabs were inoculated into Blood agar and Mannitol salt agar media. Antibiogram was done by modified Kirby Bauer disc diffusion method. MRSA were detected by oxacillin and cefoxitin disc diffusion method. The resistance was confirmed by MIC of oxacillin agar dilution method. Out of 142 samples 34 strains of Staphylococcus were isolated among them 07 (4.93%) were MRSA and 27 (19.01%) were MSSA. The carriage rate of MRSA was higher among nurse than other healthcare provider. Nasal carriage of MRSA is responsible for spreading infection from healthcare personnel to normal individual. So, regular screening of carrier is required from prevention of hospital acquired infection. Bangladesh J Med Microbiol 2017; 11 (2): 17-19


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