Antibacterial Activity of Lactobacillus spp. Against Listeria monocytogenes

2019 ◽  
Vol 10 (5) ◽  
pp. 1152
Author(s):  
Aya Talal Abdulameer Reza ◽  
Wala'a Shawkat Ali
2020 ◽  
Vol 21 (10) ◽  
pp. 980-989
Author(s):  
Sampath Shobana ◽  
Sunderam Veena ◽  
S.S.M. Sameer ◽  
K. Swarnalakshmi ◽  
L.A. Vishal

Aims: To evaluate the antibacterial activity of Artocarpus hirsutus mediated seed extract for nanoparticle synthesis. Background: Gastrointestinal bacteria are known for causing deadly infections in humans. They also possess multi-drug resistance and interfere with clinical treatments. Applied nanotechnology has been known to combat such infectious agents with little interference from their special attributes. Here we synthesize silver nanoparticles from Artocarpus hirsutus seed extract against two gastro-intestinal bacterial species: Enterobacter aerogenes and Listeria monocytogenes. Objective: To collect, dry, and process seeds of Artocarpus hirsutus for nanoparticle synthesis. To evaluate the morphological interaction of silver nanoparticles with bacteria. Methods: Artocarpus hirsutus seeds were collected and processed and further silver nanoparticles were synthesized by the co-precipitation method. The synthesized nanoparticles were characterized using XRD, UV, FTIR, and SEM. These nanoparticles were employed to study the antibacterial activity of nanoparticles against Enterobacter aerogenes and Listeria monocytogenes using well diffusion method. Further, morphological interaction of silver nanoparticles on bacteria was studied using SEM. Result: Silver nanoparticles were synthesized using Artocarpus hirsutus seed extract and characterization studies confirmed that silver nanoparticles were spherical in shape with 25-40 nm size. Antibacterial study exhibited better activity against Enterobacter aerogenes with a maximum zone of inhibition than on Listeria monocytogenes. SEM micrographs indicated that Enterobacter aerogenes bacteria were more susceptible to silver nanoparticles due to the absence of cell wall. Also, the size and charge of silver nanoparticles enable easy penetration of the bacterial cell wall. Conclusion: In this study, silver nanoparticles were synthesized using the seed extract of Artocarpus hirsutus for the first time exploiting the fact that Moraceae species have high phytonutrient content which aided in nanoparticle synthesis. This nanoparticle can be employed for large scale synthesis which when coupled with the pharmaceutical industry can be used to overcome the problems associated with conventional antibiotics to treat gastrointestinal bacteria.


2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Flávia Cíntia de Oliveira ◽  
Tamara Rezende Marques ◽  
Gustavo Henrique Andrade Machado ◽  
Thaís Cristina Lima de Carvalho ◽  
Aline Aparecida Caetano ◽  
...  

Abstract The phenolic compounds from various extracts of jabuticaba skin powder (JSP) were characterized in this study, and the antibacterial activity assessed. The phenolic compounds were extracted from the JSP using four methods: a) acetone extraction - 1 g JSP: 10 mL 70% acetone, resting for 2 hours; b) aqueous extract - 1 g JSP: 15 mL water, under agitation; c) ethanolic extract - 1 g JSP: 15 mL acidified ethanol, under agitation; and d) methanolic extract - 1 g JSP: 50 mL 50% methanol, under reflux. The antibacterial activity was evaluated by the agar diffusion assay, using Escherichia coli ATCC 11229, Salmonella choleraesuis ATCC 6539, Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538 and Listeria monocytogenes ATCC 19117. The ethanolic and methanolic extracts showed the highest levels of phenolic compounds, especially of cyanidin chloride, catechin and epicatechin. The extracts did not inhibit the growth of Escherichia coli and Salmonella choleraesuis, but inhibited 30% of the growth of Pseudomonas aeruginosa with an extract concentration of 250 µg mL-1. Against Staphylococcus aureus and Listeria monocytogenes the highest inhibitory effect observed was 41.8% for the ethanolic extract, followed by 36% inhibition by the methanolic extract, thus revealing the potential of these extracts as possible alternatives for use in the food and/or pharmaceutical industries.


Author(s):  
Krzysztof Skowron ◽  
Ewa Wałecka-Zacharska ◽  
Natalia Wiktorczyk-Kapischke ◽  
Katarzyna Grudlewska-Buda ◽  
Zuzanna Bernaciak ◽  
...  

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Apon Zaenal Mustopa ◽  
Rifqiyah Nur Umami ◽  
. Melki

<p><strong><br /></strong><em>The antibacterial activities of mangrove species, Avicennia marina, Sonneratia caseolaris (collected from Teluk Payo, Banyuasin, South Sumatera), Ceriops tagal, Rizhopora apiculata, and Sonneratia alba (collected from Sadai, South Bangka) were screened against Salmonella typhi and Listeria monocytogenes by agar disk diffusion assays. Extractions were conducted using organic solvents (methanol, ethyl acetate, and acetone, subsequently). Most of the extracts tested showed potential antibacterial activity against both pathogens. The methanol extracts of the bark from S. alba and the fruit from A. marina showed particularly large inhibition zones (15 mm) against S. typhi. The acetone extract of S. alba leaves showed the largest inhibition zone (14 mm) when tested against L. Monocy-togenes. Further partial purifications of selected extracts which showed strong inhibition were performed by silica gel column chromatography using various eluent compositions with different polarities. The third fraction of methanol extract from S.alba leaves eluted with chloroform:methanol (1:5) resulted in a remarkably large inhibition zone (23 mm) against S. typhi. The third and seventh fractions of acetone extract from S. alba leaves eluted with ethyl acetate:methanol (7:3) resulted in a large inhibition zones (15 mm) against L. monocytogenes. In addition, the sixth fraction of methanol extract from A. marina fruit eluted with chloroform : methanol (6:4) resulted in the largest inhibition zone (17 mm) against L. monocytogenes. These results indicated that mangrove extracts could be developed as potential biomaterials for biopharmaceutical as well as biopreservation industries.</em></p><p><em><strong>Keywords</strong>: antibacterial activity, mangrove, column chromatography</em></p>


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