scholarly journals Synergistic Activity and Biofilm Formation Effect of Colistin Combined with PFK-158 Against Colistin-Resistant Gram-Negative Bacteria

2021 ◽  
Vol Volume 14 ◽  
pp. 2143-2154
Author(s):  
Liqiong Chen ◽  
Kaihang Yu ◽  
Lijiang Chen ◽  
Xiangkuo Zheng ◽  
Na Huang ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Gram Negative

scholarly journals Using sub-micron silver-nanoparticle based films to counter biofilm formation by Gram-negative bacteria

2018 ◽  
Vol 442 ◽  
pp. 288-297 ◽  
Author(s):  
A.R. Gillett ◽  
S.N. Baxter ◽  
S.D. Hodgson ◽  
G.C. Smith ◽  
P.J. Thomas
Keyword(s):  
Silver Nanoparticle ◽  
Biofilm Formation ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals Relationship Between Membrane Vesicles, Extracellular ATP and Biofilm Formation in Antarctic Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nicolas Baeza ◽  
Elena Mercade
Keyword(s):  
Biofilm Formation ◽  
Membrane Vesicles ◽  
Metabolic Cost ◽  
Extracellular Atp ◽  
Gram Negative Bacteria ◽  
Bacterial Survival ◽  
Gram Negative ◽  
Two Factors ◽  
And Control

Abstract Biofilms offer a safe environment that favors bacterial survival; for this reason, most pathogenic and environmental bacteria live integrated in biofilm communities. The development of biofilms is complex and involves many factors, which need to be studied in order to understand bacterial behavior and control biofilm formation when necessary. We used a collection of cold-adapted Antarctic Gram-negative bacteria to study whether their ability to form biofilms is associated with a capacity to produce membrane vesicles and secrete extracellular ATP. In most of the studied strains, no correlation was found between biofilm formation and these two factors. Only Shewanella vesiculosa M7T secreted high levels of extracellular ATP, and its membrane vesicles caused a significant increase in the speed and amount of biofilm formation. In this strain, an important portion of the exogenous ATP was contained in membrane vesicles, where it was protected from apyrase treatment. These results confirm that ATP influences biofilm formation. Although the role of extracellular ATP in prokaryotes is still not well understood, the metabolic cost of its production suggests it has an important function, such as a role in biofilm formation. Thus, the liberation of extracellular ATP through membrane vesicles and its function deserve further study.

scholarly journals The effects of biofilm and selective mixed culture on the electricity outputs and wastewater quality of tempe liquid waste based microbial fuel cell

REAKTOR ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 84
Author(s):  
Tania Surya Utami ◽  
Rita Arbianti ◽  
M Mariana ◽  
Nathania Dwi Karina ◽  
Vifki Leondo
Keyword(s):  
Wastewater Treatment ◽  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Mixed Culture ◽  
Biofilm Formation ◽  
Formation Time ◽  
Electricity Production ◽  
Gram Negative Bacteria ◽  
Treatment Unit ◽  
Gram Negative

Microbial Fuel Cell (MFC) technology is highly prospective to be developed because it could be utilized as the alternative electricity sources and simultaneously as the wastewater treatment unit using microorganism as catalyst. Industrial Tempe wastewater has the potential to be used as MFC substrate since it still contains high nutrition for microbe and could pollute the environment if it disposed before being processed first. This study focused on investigating the effect of selective mixed culture addition and biofilm formation on the electricity production and the wastewater treatment aspects with tubular single chamber membranless reactor and industrial Tempe wastewater substrate. The result showed that, with the addition of selective mixed culture, the optimum electricity production obtained with addition of 1 ml gram-negative bacteria with increase in electricity production up to 92.14% and average voltage of 17.91 mV, while the optimum decreased levels of COD and BOD obtained with addition of 5 ml gram-negative bacteria which are 29.32% and 51.32%. On the biofilm formation experiment, optimum electricity production obtained from biofilm formation time for 14 days with increase in electricity production up to 10-folds and average voltage of 30.52 mV, while the optimum decreased levels of COD and BOD obtained from biofilm formation time for 7 days which are 18.2% and 35.9%.Keywords : biofilm, Microbial Fuel Cell, selective mixed culture, Tempe wastewater, tubular reactor

Antimicrobial Activity of Gentiana lutea L. Extracts

2009 ◽  
Vol 64 (5-6) ◽  
pp. 339-342 ◽  
Author(s):  
Katarina Šavikin ◽  
Nebojša Menković ◽  
Gordana Zdunić ◽  
Tatjana Stević ◽  
Dragoja Radanović ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Secondary Metabolites ◽  
Antimicrobial Effect ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Gram Negative ◽  
Gentiana Lutea ◽  
Methanolic Extracts ◽  
Pure Compounds

Methanolic extracts of flowers and leaves of Gentiana lutea L., together with the isolated compounds mangiferin, isogentisin and gentiopicrin, were used to investigate the antimicrobial activity of the plant. A variety of Gram-positive and Gram-negative bacteria as well as the yeast Candida albicans has been included in this study. Both extracts and isolated compounds showed antimicrobial activity with MIC values ranging from 0.12 - 0.31 mg/ml. Our study indicated that the synergistic activity of the pure compounds may be responsible for the good antimicrobial effect of the extracts. Quantification of the secondary metabolites was performed using HPLC

Escherichia coli tol and rcs genes participate in the complex network affecting curli synthesis

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2487-2497 ◽  
Author(s):  
Anne Vianney ◽  
Grégory Jubelin ◽  
Sophie Renault ◽  
Corine Dorel ◽  
Philippe Lejeune ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Membrane Integrity ◽  
Regulatory Proteins ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Dominant Effect ◽  
Gram Negative ◽  
E Coli

Curli are necessary for the adherence of Escherichia coli to surfaces, and to each other, during biofilm formation, and the csgBA and csgDEFG operons are both required for their synthesis. A recent survey of gene expression in Pseudomonas aeruginosa biofilms has identified tolA as a gene activated in biofilms. The tol genes play a fundamental role in maintaining the outer-membrane integrity of Gram-negative bacteria. RcsC, the sensor of the RcsBCD phosphorelay, is involved, together with RcsA, in colanic acid capsule synthesis, and also modulates the expression of tolQRA and csgDEFG. In addition, the RcsBCD phosphorelay is activated in tol mutants or when Tol proteins are overexpressed. These results led the authors to investigate the role of the tol genes in biofilm formation in laboratory and clinical isolates of E. coli. It was shown that the adherence of cells was lowered in the tol mutants. This could be the result of a drastic decrease in the expression of the csgBA operon, even though the expression of csgDEFG was slightly increased under such conditions. It was also shown that the Rcs system negatively controls the expression of the two csg operons in an RcsA-dependent manner. In the tol mutants, activation of csgDEFG occurred via OmpR and was dominant upon repression by RcsB and RcsA, while these two regulatory proteins repressed csgBA through a dominant effect on the activator protein CsgD, thus affecting curli synthesis. The results demonstrate that the Rcs system, previously known to control the synthesis of the capsule and the flagella, is an additional component involved in the regulation of curli. Furthermore, it is shown that the defect in cell motility observed in the tol mutants depends on RcsB and RcsA.

scholarly journals Improving Antibacterial and Anti-biofilmic properties of urological catheters with Eucalyptus, Rosemary, Green tea and Ziziphora extracts by impregnation method

2021 ◽  
Author(s):  
Najme Akhlaghi-Ardekani ◽  
Davod Mohebbi-Kalhori ◽  
Abdolreza samimi ◽  
Reza Karazhyan
Keyword(s):  
Green Tea ◽  
Biofilm Formation ◽  
Antibacterial Agents ◽  
Antibacterial Properties ◽  
Polymer Materials ◽  
Gram Negative Bacteria ◽  
Impregnation Method ◽  
Herbal Extracts ◽  
Urinary Catheters ◽  
Gram Negative

Abstract The main complications of urinary catheters are the bacteria's biofilm formation and the urinary tract infection caused by gram-positive and gram-negative bacteria. In the recent years, the attention has changed its direction toward the antimicrobial, anti-biofilmic, and hydrophobicity effects of herbal extracts. Some of these extracts can inhibit the colonization of the two bacteria Staphylococcus aureus and Escherichia coli which are resistant to antibiotics. These bacteria can stick to the surface of polymer materials due to their hydrophobicity. Thus, antibacterial hydrophilic herbal extracts are supposed to help reduce the risk of the surficial infection if they are used to impregnate the urinary catheters. In this research, the extracts of these four plants eucalyptus, rosemary, green tea and ziziphora were used as the antibacterial agents. After the impregnation and modification of the sample catheters, they were tested by AFM, FE-SEM, ATR-FTIR methods to measure their mechanical, chemical, and hydrophilic properties, during the 21-day experiment period, compared to non-impregnated ones. The tests showed the silicone catheters impregnated by the herbal extracts have some significant anti-biofilmic and antibacterial properties (P˂0.0001) due to the increase in their hydrophilic property. The impregnated catheters could be release the extracts and killed bacteria in 21 days Therefore; some herbal extracts can be good alternatives to chemical drugs.

scholarly journals ANTIBACTERIAL AND ANTI-YEAST EFFECTS OF SOME ESSENTIAL OILS

2018 ◽  
pp. 68-76
Author(s):  
Urjinlham R ◽  
Oyunbileg B ◽  
Anumandal O ◽  
Sainbileg P ◽  
Rentsenkhand Ts
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Mentha Piperita ◽  
Lag Phase ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Aromatic Plants ◽  
Gram Positive ◽  
Gram Negative ◽  
Ledum Palustre

Essential oils from aromatic plants of Ledum palustre L. and Mentha piperita L. were extracted using steam distillation and the antimicrobial effects were evaluated alone and in combinations against food-borne pathogens of Gram-positive and Gram-negative bacteria and food related-yeasts (Bacillus subtilis, Escherichia coli, Saccharomyces cerevisiae, Schizosaccharomyce spombe, and Geotrichum candidum). Essential oils from two aromatic plants used in this study showed the antimicrobial activity against bacteria and yeast, which was found to be concentration dependent. The effects of Ledum palustre L. and Mentha piperita L. plants essential oils against yeast and Gram-negative bacteria at concentrations of 0.5 ul/ml and 0.25 ul/ml extended lag phase or adaptation phase by 48 hours, respectively. Gram-positive bacteria were found to be susceptible to the studied two plants essential oils. When the effects of antimicrobial activity of two essential oils were tested in combination against bacteria and yeast in vitro, the MIC value was in the range of 0.125-0.5 ul/ml and showed synergistic activity against E.coli and additive values against B.subtilis and S.cerevisiae. 

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