Biosynthesis of silver nanoparticles using Bacillus subitilis and its antibacterial activity

2021 ◽  
Vol 30 (2) ◽  
pp. 67-71
Author(s):  
Ghada S.M. Abd el wahab

Background: Silver nanoparticles (AgNPs) have recently been extensively investigated because of their superior physical, chemical, and biological characteristics, and their superiority is primarily due to the size, shape, composition, crystallinity, and structure of AgNPs compared to their bulk forms. Objective: The current study aimed to investigate the antibacterial activity of silver nanoparticles (AgNPs) synthesized intracellular by using standard strain Bacillus subitilis ATCC 6633 against reference strains Escherichia coli ATCC 2592 and Staphylococcus aureus ATCC 29737. Results: The synthesized AgNPs showed potent antibacterial activities against the two tested bacterial strains with inhibition zones ranged from 42 -52mm and MIC 27.2 µg / ml. The silver nanoparticles were characterized with particle size ≃ 100 nm and zeta potential -19. There was deformation in both tested strains upon treatment with AgNPs which was observed by Scanning Electron Microscopy (SEM). Conclusion: The results indicated that AgNPs could be used as an effective antibacterial agent.

2020 ◽  
Vol 1 (1) ◽  
pp. 27-36
Author(s):  
Jendri Mamangkey

The present study was conducted aiming to isolate and characterize endophytic bacterial isolates with antibacterial ability, phosphate solubilization, and proteolytic activity from rhizomes of the Zingiberaceae family (Etlingera sp., Globba patens, Globba pendula, and Zingiber multibracteata). Nineteen bacterial isolates were obtained from Zingiberaceae rhizomes with isolate codes of EZS27, EZS18, EZS19, EZS25, EZS16, EZS08, EZS09, EZS13, EZS20, EZS14, EZS10, EZS11, EZS03, EZS05, EZS06, EZS43, EZS45, EZS47, and EZS28. The screening of the endophytes for antibacterial activity was done through the paper disc method. Four bacterial isolates presented antibacterial activities. EZS06 isolate inhibited the growth of EPEC (11 mm), P. vulgaris ATCC 13315 (10 mm), and L. monocytogenes BTCC B693 (9 mm). Also, EZS20 isolate inhibited the growth of S. aureus ATCC 29213 (17 mm), EZS28 isolate inhibited MRSA ATCC 43300 (8.6 mm), and EZS45 isolate inhibited S.  Epidermidis ATCC 12228 (9 mm). The EZS19, EZS03, and EZS16 isolates dissolved the phosphate most effectively. Eight isolates (EZS19, EZS47, EZS27, EZS25, EZS09, EZS20, EZS45, and EZS06) showed the best protease activity. In general, our results showed that the endophytic bacterial strains can be used as a new and useful antibacterial agent since it showed antibacterial activity and chemical diversity. Furthermore, it also has the potential for exploitation in a wide variety of medical, agricultural, and industrial areas.


2021 ◽  
Vol 22 (1) ◽  
pp. 28-34
Author(s):  
Saddam Hussain Bughio

The objective of this study was to investigate the impact of phytochemical analysis and the antibacterial activity of extracts of stem, flowers and leaves of Tamarix dioica Roxb. ex Roth. Four solvents namely, diethyl ether, ethyl acetate, methanol and acetone were selected to obtain extracts from different parts of the plant. The organic solvent extracts were investigated for phytochemical analysis and antibacterial activity against two bacterial strains, namely Escherichia coli and Staphylococcus aureus. The result of phytochemicals revealed the presence of various constituents, such as phlobatannins, tannins, saponins, alkaloids, phenols, proteins, terpenoids, flavonoids and steroids by using standard procedures. Most of these components were present in methanol and ethyl acetate extract. Therefore, four out of two extracts, such as methanol and ethyl acetate extracts from stems, flowers, and leaves, were used to test their evidence of antibacterial activity. From this, it was observed that the methanol extracts of stem, flowers and leaves of T. dioica were highly effective together with E. coli and S. aureus with a minimum inhibitory concentration (MIC) value of 500 μg/mL. Considering that the ethyl acetate (EA) extracts from the stem, flowers and leaves of T. dioica were examined to be ineffective against E. coli and S. aureus and MIC values were not observed in two strains of bacteria.


2018 ◽  
Vol 16 (S1) ◽  
pp. S48-S54
Author(s):  
Y. Ez zoubi ◽  
S. Lairini ◽  
A. Farah ◽  
K. Taghzouti ◽  
A. El Ouali Lalami

The purpose of this study was to determine the chemical composition and to evaluate the antioxidant and antibacterial effects of the Moroccan Artemisia herba-alba Asso essential oil against foodborne pathogens. The essential oil of Artemisia herba-alba was analyzed by gas chromatography coupled with mass spectroscopy. The antibacterial activity was assessed against three bacterial strains isolated from foodstuff and three bacterial strains referenced by the ATCC (American Type Culture Collection) using the disk diffusion assay and the macrodilution method. The antioxidant activity was evaluated using the DPPH (2, 2-diphenyl-1- picrylhydrazyl) method. The fourteen compounds of the Artemisia herba-alba essential oil were identified; the main components were identified as β-thujone, chrysanthenone, α-terpineol, α-thujone, α-pinene, and bornyl acetate. The results of the antibacterial activity obtained showed a sensitivity of the different strains to Artemisia herba-alba essential oil with an inhibition diameter of 8.50 to 17.00 mm. Concerning the MICs (minimum inhibitory concentrations), the essential oil exhibited much higher antibacterial activity with MIC values of 2.5 μl/ml against Bacillus subtilis ATCC and Lactobacillus sp. The essential oil was found to be active by inhibiting free radicals with an IC50 (concentration of an inhibitor where the response is reduced by half) value of 2.9 μg/ml. These results indicate the possible use of the essential oil on food systems as an effective inhibitor of foodborne pathogens, as a natural antioxidant, and for potential pharmaceutical applications. However, further research is needed in order to determine the toxicity, antibacterial, and antioxidant effects in edible products.


2021 ◽  
Vol 22 (7) ◽  
pp. 3539
Author(s):  
Anastasia Meretoudi ◽  
Christina N. Banti ◽  
Panagiotis K. Raptis ◽  
Christina Papachristodoulou ◽  
Nikolaos Kourkoumelis ◽  
...  

The oregano leaves’ extract (ORLE) was used for the formation of silver nanoparticles (AgNPs(ORLE)). ORLE and AgNPs(ORLE) (2 mg/mL) were dispersed in polymer hydrogels to give the pHEMA@ORLE_2 and pHEMA@AgNPs(ORLE)_2 using hydroxyethyl–methacrylate (HEMA). The materials were characterized by X-ray fluorescence (XRF) spectroscopy, X-ray powder diffraction analysis (XRPD), thermogravimetric differential thermal analysis (TG-DTA), derivative thermogravimetry/differential scanning calorimetry (DTG/DSC), ultraviolet (UV-Vis), and attenuated total reflection mode (ATR-FTIR) spectroscopies in solid state and UV–Vis in solution. The crystallite size value, analyzed with XRPD, was determined at 20 nm. The antimicrobial activity of the materials was investigated against Gram-negative bacterial strains Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli). The Gram-positive ones of the genus of Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus) are known to be involved in microbial keratitis by the means of inhibitory zone (IZ), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The IZs, which developed upon incubation of P. aeruginosa, E. coli, S. epidermidis, and S. aureus with paper discs soaked in 2 mg/mL of AgNPs(ORLE), were 11.7 ± 0.7, 13.5 ± 1.9, 12.7 ± 1.7, and 14.3 ± 1.7 mm. When the same dose of ORLE was administrated, the IZs were 10.2 ± 0.7, 9.2 ± 0.5, 9.0 ± 0.0, and 9.0 ± 0.0 mm. The percent of bacterial viability when they were incubated over the polymeric hydrogel discs of pHEMA@AgNPs(ORLE)_2 was interestingly low (66.5, 88.3, 77.7, and 59.6%, respectively, against of P. aeruginosa, E. coli, S. epidermidis, and S. aureus) and those of pHEMA@ORLE_2 were 89.3, 88.1, 92.8, and 84.6%, respectively. Consequently, pHEMA@AgNPs(ORLE)_2 could be an efficient candidate toward the development of non-infectious contact lenses.


Author(s):  
Olufunmiso O. Olajuyigbe ◽  
Morenike O. Adeoye-Isijola ◽  
Otunola Adedayo

Background: Black soap is a medicinal product that could be harnessed for economic purpose if properly packaged, and misconception about its traditional use by herbalists is thrown overboard.Aims: To promote the relevance of these soaps for economic development, this study compared the antibacterial activity of black soaps with medicated soaps widely used against bacterial infections.Methods: The antibacterial activities of these soap samples were determined by agar diffusion and macrobroth dilution methods.Results: In this study, the statistical analysis of the inhibition zones showed that black soaps were significantly (p < 0.05) more active than medicated soaps used against the test bacterial isolates. The black soaps inhibited and killed the isolates better than the medicated soaps at the different concentrations used. The minimum inhibitory concentration for Klebsiella pneumoniae and Enterococcus faecalis ranged between 0.125 mg/mL and 2 mg/mL, Staphylococcus aureus (0.25–4) mg/mL, Escherichia coli (0.125–4) mg/mL and Pseudomonas aeruginosa (1–4) mg/mL. The result showed that K. pneumoniae and E. faecalis were the most susceptible, followed by E. faecalis > E. coli > S. aureus > P. aeruginosa.Conclusion: As a valuable medicinal output derivable from organic waste product that could be converted to wealth, African black soap production, utilisation and commercialisation have tremendous economic potentials. These soaps showed significant antibacterial activity greater than those of the medicated soaps. Hence, their use could be a better option in place of commercially available medicated and antiseptic soaps because of the degree of antibacterial activities they exhibited.


Author(s):  
Gouse Basha Sheik ◽  
Muazzam Sheriff Maqbul ◽  
Gokul Shankar S. ◽  
Ranjith M S

Objective: To isolate and characterize novel actinomycetes and to evaluate their antibacterial activity against drug-resistant pathogenic bacteriaMethods: In the present study, 19 soil samples were collected from different localities of Ad-Dawadmi, Saudi Arabia. Actinomycetes were isolated from these samples using serial dilution and plating method on Actinomycetes isolation agar supplemented with nalidixic acid and actidione to inhibit bacteria and fungi. Crude extracts of potential actinomycetes were produced by submerged fermentation. The antimicrobial activity of crude extracts of actinomycetes was tested against different bacteria using the agar well diffusion method. Characterization of the isolates was done by morphological, physiological and biochemical methods.Results: A total of 9 (47%) isolates of actinomycetes were isolated from 19 different soil samples tested. Among them, 4 (44%) isolates confirmed as Streptomyces sp. showed potential antimicrobial activity against one or more test organisms. Crude extracts were made from these 4 actinomycetes isolates(DOM1, DOM3, DP3, DP4)and tested for their antibacterial activities against 4 different clinical bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus). Crude extract from DP3 isolate showed highest antibacterial activity against all the four test organisms (28 mm, 21 mm, 20 mm and 18 mm) respectively and DP4 showed lowest antibacterial activity against all the four test organisms (14 mm, 12 mm, 0 mm, 6 mm) respectively. The highest zone of inhibition was shown by DP3 against Staphylococcus aureus (28 mm) and Escherichia coli was resistant for DP4. Most of the Inhibition zones produced by crude extracts showed significant differences when compared with control, tested against test organisms (P<0.05). Inhibition zones produced by DP3 and DOM1 against Staphylococcus aureus were 28 mm and 23 mm, respectively which were strong active when compared with control Ciprofloxacin (18 mm).Conclusion: Further studies for purification of bioactive metabolites and molecular characterization analysis of isolated Streptomyces sp. are in progress which would be helpful in discovering novel compounds of commercial value.


2016 ◽  
Vol 3 (1) ◽  
pp. 65-66
Author(s):  
Arumugasamy K ◽  
Nantha Kumar R ◽  
Abdul Kaffoor H ◽  
Shalimol A

The methanolic rhizome extract of A. calcarata was evaluated for its antibacterial activities against five bacterial strains Pseudomonas aeuroginosa, Proteus vulgaris, Salmonella paratyphi, Bacillus thurungiensis and Staphylococcus faccealis. The extract has inhibited all the tested bacterial species with different manner at various concentration. However the higher level zone of inhibition in 400 (mg/ml) is significant against all the above said bacterial strains of these Salmonella paratyphi. Based on the present study it can be conculuded that the plant rhizome possess potent anti bacterial activity.


Author(s):  
R. Cabrera-Contreras ◽  
R. Morelos-Ramírez ◽  
J. P. Quiróz-Ríos ◽  
D. Muñoz-Quiróz

Essential oils (EOs) are commonly used in food industry, due that they possess antioxidative and antimicrobial properties. There are few essential oils that have been used in medicine, due to its potent antibacterial activity against intrahospital pathogens. OEO has experimentally shown potent antibacterial effect on nosocomial Gram-positive bacteria, therefore it can be very useful in hospital environments, where there are many bacterial pathogens, which are the etiological agents of nosocomial infections and most of them are resistant to several antibiotics. Objective: The aim of this study was to determine antimicrobial effect of OEO on most frequent bacterial intrahospital pathogens: MRSA, MRSE comparatively to selected ATCC bacterial reference strains. Methods: This experimental study investigates the antibacterial action of oregano (Origanum vulgare) essential oil (OvEO) on two human pathogens: Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) Here, we used OEO against one of the most prominent antibiotic-resistant bacterial strains: methicillin-resistant SA (MRSAmecA+ = Meticillin Resistant SA and mecA- = Meticillin Resistance SA ), methicillin-resistant SE (MRSEmecA+ = Meticillin Resistance Staphylococcus epidermidis mecA+) and reference strains: S. aureus ATCC 700699, S. epidermidis ATCC 359845 and E. coli ATCC 25922. Bactericidal effects of the OEO on these bacteria were mainly evaluated using undiluted and four serial dilutions in coconut oil (CCO) l: 1:10, 1:100, 1:200, 1:400. Results: OEO, undiluted and 4 serial dilutions showed potent antibacterial activity against all strains tested. In conclusion, this OEO could be used as an alternative in medicine. The ability of OEO to inhibit and kill clinical Multi-Drug-Resistant (MDR): MRSA and MRSE strains, highlights it´s potential for use in the management of drug-resistant MDR infections in hospitals wards.


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