Antibacterial Effects of Biosynthesized Silver Nanoparticles on Surface Ultrastructure and Nanomechanical Properties of Gram-Negative Bacteria viz. Escherichia coli and Pseudomonas aeruginosa

2016 ◽  
Vol 8 (7) ◽  
pp. 4963-4976 ◽  
Author(s):  
Baskaran Ramalingam ◽  
Thanusu Parandhaman ◽  
Sujoy K. Das
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Gram Negative Bacteria ◽  
Antibacterial Effects ◽  
Surface Ultrastructure ◽  
Gram Negative ◽  
Nanomechanical Properties

scholarly journals Green Synthesis of Silver Nanoparticles Using Novel Launaea Procumbens Leaves Extract and Screening Its Antibacterial Activity

2021 ◽  
Author(s):  
Sanjay Ratan Kumavat ◽  
SATYENDRA MISHRA
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Gram Negative Bacteria ◽  
Zone Of Inhibition ◽  
Gram Negative ◽  
Green Synthesized Silver Nanoparticles ◽  
Launaea Procumbens

Abstract Plants are emerging as a cost-effective and ecofriendly method for green synthesis of nanoparticles. The plant extract Launaea procumbens was used as a reduction agent in the green synthesis of silver nanoparticles. UV-Visible spectroscopy, HR-TEM, SAED, FE-SEM, EDAX, DLS, and FT-IR were used to study the green synthesized silver nanoparticles. UV-Vis spectroscopy of a prepared silver solution revealed maximum absorption at 435 nm. The synthesized silver nanoparticles were found to be spherical in shape with a size in the range of 24.28 to 31.54 nm. DLS analysis was used to determine the size of the green synthesized silver nanoparticles, which showed outstanding antibacterial action against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, as well as Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Gram-positive Bacillus subtilis had a maximum zone of inhibition of 20 mm, Staphylococcus aureus had a zone of inhibition of 19 mm, and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa had zones of inhibition of 13 mm.

scholarly journals MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

scholarly journals Emergence of Colistin Resistant Gram-Negative Bacteria in a Tertiary Care Rural Hospital in 2019

KYAMC Journal ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 87-90
Author(s):  
Abdullah Akhtar Ahmed ◽  
Nusrat Akhtar Juyee ◽  
SM Ali Hasan
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Tertiary Care ◽  
Salmonella Typhi ◽  
Rural Hospital ◽  
Gram Negative Bacteria ◽  
Bacterial Isolates ◽  
Colistin Resistance ◽  
Sensitivity Testing ◽  
Gram Negative

Background: Colistin-resistant Gram-negative bacteria is a rapidly emerging global threatgenerated a sense of public alarm. Objective: To combat this challenge a study was designedto evaluate the fast spreading infections by colistin-resistant pathogens in the tertiary care rural hospital of Bangladesh. Materials and Methods: To study isolation ofpathogenic gram-negative bacilli,clinical sample (n-640) of hospitalized patients of Khwaja Yunus Ali Medical College Hospital in Enayetpur, Bangladesh during the 1st quarter of the year 2019 were used. The bacterial isolates were screened for meropenem and colistin-resistance. Results: A total of 156 bacterial isolates were studied which included Escherichia coli (n-112), Klebsiella pneumoniae (n-14), Pseudomonas aeruginosa (n-27), and Salmonella typhi (n-3). Antibiotic sensitivity testing showed that 32/156(20%) and 119/156 (76%) isolates were resistant to meropenem and colistin, respectively. whereas 50/156 (32%) isolates were resistant to both antibiotics. Escherichia coli, K. pneumoniae, pseudomonas aeruginosa, and Salmonella typhi isolates respectivelywere 112/156 (72%), 14/156 (9%). 27/156 (17%), and 3/156 (2%). Conclusion: Colistin is typically used as salvage therapy, or last-line treatment, for MDR gramnegative infections.But there is worrisome therapeutic scenario in our study finding of colistin resistance is 76% in Gram-negative bacteria of the clinical isolates. The restricted and rational use of colistin drug is the need of hour. KYAMC Journal Vol. 11, No.-2, July 2020, Page 87-90

scholarly journals National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Po-Yu Liu ◽  
Yu-Lin Lee ◽  
Min-Chi Lu ◽  
Pei-Lan Shao ◽  
Po-Liang Lu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Gram Negative Bacteria ◽  
National Surveillance ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant

ABSTRACT A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

Susceptibility of Gram-negative bacteria to the synergistic bactericidal action of serum and polymyxin B nonapeptide

1986 ◽  
Vol 32 (1) ◽  
pp. 66-69 ◽  
Author(s):  
Petri Viljanen ◽  
Helena Käyhty ◽  
Martti Vaara ◽  
Timo Vaara
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Enterobacter Cloacae ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Bactericidal Action ◽  
Gram Negative ◽  
Degree Of Sensitization ◽  
Normal Human ◽  
Klebsiella Spp

Polymyxin B nonapeptide was able to sensitize Escherichia coli strains and strains of Salmonella typhimurium, Klebsiella spp., Enterobacter cloacae, Pseudomonas aeruginosa, and Haemophilus influenzae to the bactericidal action of fresh normal human serum. The degree of sensitization varied significantly within the strains. Strains of Proteus mirabilis, Neisseria gonorrhoeae, and N. meningitidis remained resistant.

scholarly journals Gram Negative Bacteria (GNB) Isolated From Used Home-made and Surgical Nose/Face Mask by Local Residents of Akungba Akoko, Ondo State, a Threat to Life and False Sense of Protection against SARS-CoV-2 (COVID-19)

2021 ◽  
pp. 1-17
Author(s):  
Oludare Temitope Osuntokun
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Proteus Mirabilis ◽  
Antimicrobial Agents ◽  
Face Mask ◽  
Gram Negative Bacteria ◽  
Haemophilus Influenza ◽  
Gram Negative ◽  
False Sense ◽  
Zones Of Inhibition

Nose/Face masks are physical barriers to respiratory droplets that may enter through the nose and mouth to cause infections in the respiratory tract. The study was determined and assess the presence of Gram-negative bacteria in used home-made and surgical nose mask by residents of Akungba-Akoko Ondo State and to determine the antimicrobial susceptibility and resistant profile of the isolated bacteria to eight (8) different antimicrobial agents. The antimicrobial analysis were performed using standard microbiological and biochemical methods. Antimicrobial Susceptibility test of all identified isolates to antimicrobial agents were determined using the standard Kirby-Bauer disk diffusion method. The Gram-negative bacteria that were detected from the used home-made and surgical nose mask in this study include: Haemophilus influenza, Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia. During this study, all the Gram-negative bacteria isolates were resistant to Ciproflox in both used home-made and surgical nose mask. All isolates were also resistant to Ampicilin, Augmentin, Septrin and Streptomycin. In this study, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were isolated organism from used home-made nose mask, it was observed that Escherichia coli were resistant to Augmentin, Tarivid, Ciproflox, Gentamycin, and Reflaxine, and Pseudomonas aeruginosa were resistant to Tarivid, Ciproflox, and Nalidixic acid between 20 mm and 24 mm zones of inhibition respectively. Haemophilus influenza, Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis were isolated organism from used surgical nose mask. It was observed that all isolated organisms from the used surgical nose/face mask were resistant to Augmentin and Gentamycin between 20 and 24 mm zones of inhibition respectively. Klebsiella pneumoniae were isolated from both used home-made and surgical nose/face mask and were found to be resistant to Streptomycin, Septrin, Ampicilin, and Gentamicin between 20 to 22 mm zones of inhibition respectively. Proteus mirabilis were isolated from used surgical nose/face mask,        they were found to be resistant to Ciproflox at 21mm zones of inhibition. Haemophilus influenza were resistant to Ampicilin, Septrin, Streptomycin, and Augmentin at 23 mm zones of inhibition. Isolates from used both home-made and surgical nose/face mask were subjected to modified and synergized antibiotics, it was observed that the isolates from both used home-made and surgical nose mask were resistant to all modified and synergized antibiotics between 20 and 25 mm zones of inhibition respectively. The result of this study validates the potency of  Gram negative bacteria isolated from used both home-made and surgical nose/face mask and the degree of invasion and evasiveness, thereby causing various degrees of infections and a false sense of protection against SARS-CoV-2 (COVID-19). Finding from this research recommends a stringent measures were needed to be implemented, to halt and combat this revenging situation especially in the new era of mutating SARS-CoV-2 Virus not only in Nigeria, worldwide at large.

scholarly journals QUANTITATIVE ESTIMATION AND ANTIMICROBIAL POTENTIAL OF ETHANOL EXTRACT OF DURIO ZIBETHINUS MURR. LEAVES

2017 ◽  
Vol 10 (9) ◽  
pp. 251
Author(s):  
Sridevi Chigurupati ◽  
Jahidul Islam Mohammad ◽  
Shantini Vijayabalan ◽  
Narmatha Devi Vaipuri ◽  
Kesavanarayanan Krishnan Selvarajan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Quantitative Estimation ◽  
Antibacterial Properties ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Human Pathogens ◽  
Gram Negative ◽  
Antimicrobial Potential ◽  
Durio Zibethinus

Objectives: Current research is aimed to investigate the natural antimicrobial potential of Durio zibethinus murr. ethanol leaves extract (DZL).Methods: DZL was subjected to the preliminary phytochemical screening along with quantitative analysis of phenols and flavonoids. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were recorded. The agar well diffusion method was used to measure the antibacterial activity against gram positive and gram negative bacteria. The microorganisms used for the study were the ATCC strains of Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes, Neisseria gonorrhoeae, Pseudomonas aeruginosa and Escherichia coli.Results: DZL exhibited the highest MIC of 0.1mg/mL and MBC of 0.25 mg/mL against gram negative bacteria, Pseudomonas aeruginosa and Escherichia coli. At MIC of 0.1mg/mL, DZL displayed significant zone of inhibition against Pseudomonas aeruginosa and Escherichia coli compared to gentamycin.Conclusion: This research has shown that DZL has natural antibacterial properties against gram negative human pathogens.

scholarly journals SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SILVER NANOPARTICLES STABILIZED BY CITRATE ANIONS

2020 ◽  
Vol 2020 (60) ◽  
pp. 127-135
Author(s):  
Liliya BAZYLYAK ◽  
◽  
Andriy KYTSYA ◽  
Ilona KARPENKO ◽  
Olena KARPENKO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Cell Walls ◽  
Colloidal Silver ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Vis Spectroscopy

Widespread use of synthetic antimicrobial drugs leads to the development of antibiotic resistance of pathogenic strains of microorganisms. Therefore, today researchers are very interested in drugs based on nanoparticles of metals, in particular silver and copper, which have antibacterial, antifungal and antiviral activity. One of the reasons for the high interest of researchers in AgNPs as an antimicrobial agent is the significantly lower toxicity of AgNPs compared to Ag+ ions. High antibacterial efficiency of silver nano¬particles is achieved due to their developed surface, which provides maximum contact with the environment. In addition, such nanoparticles are quite small and are able to penetrate cell membranes, to affect intracellular processes from within. Therefore, the aim of this work was to obtain concentrated colloidal silver solutions stabilized by citrate anions, which simultaneously provide satisfactory stabilization of colloidal silver solutions and are non-toxic, as well as to investigate the antimicrobial action of synthesized AgNPs. The solution of citrate stabilized silver nanoparticles (AgNPs) have been obtained via the reaction of reduction of silver nitrate by hydrazine in alkaline medium in the presence of sodium citrate. AgNPs were investigated using transmission electron microscopy (TEM) and UV-vis spectroscopy and the particles size and particles size distribution (PSD) were determined. It was observed that obtained AgNPs are mainly spherical shape. It was found that the mean diameter and PSD of AgNPs determined using TEM and UV-vis spectroscopy are close and equal to 14 and 5 nm and 15 and 4 nm respectively. Obtained solution was concentrated by evaporation at 70 C under reduced pressure up to achievement of AgNPs concentration equal to 200 mg/L. On the base of comparison of optical properties of initial silver sol and concentrated solution the minority of agglomeration of AgNPs was statement. At the same time AgNO3 test showed no change of UV-vis spectrum of concentrate that points on the absence of reducing agent in the solution; this fact indicate that hydrazine was eliminated from during the evaporation of initial AgNPs solution and obtained concentrate did not consist the toxic impurities. Antimicrobial activity of obtained citrate stabilised AgNPs against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacterium was tested using disk diffusion method. It was found that AgNPs shown significant bactericidal effect even at low (25 mg/L) concentration as well as some higher efficiency against Gram-negative bacterium. There was also a slightly higher antimicrobial activity of the drug against gram-negative bacteria Escherichia coli compared with gram-positive bacteria Bacillus subtilis, due to the different structure of cell walls. In particular, the walls of gram-positive bacteria consist mainly of peptidoglycan (murein), and gram-negative bacteria have cell walls with a layer of peptidoglycan and an outer membrane with a lipopolysaccharide component, which is not present in gram-positive bacteria. Based on the studies, it can be concluded that the proposed method of synthesis of AgNPs is suitable for obtaining highly concentrated silver sols. This method of synthesis is simple in hardware design, scalable, and the resulting colloidal solutions are stable and do not contain harmful impurities. Therefore, due to the high antibacterial activity of citrate-anion-stabilized AgNPs against certain types of gram-positive and gram-negative bacteria, it can be recommended for the manufacture of bactericidal drugs for biomedical purposes.

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