scholarly journals Electrical spiking in bacterial biofilms

2015 ◽  
Vol 12 (102) ◽  
pp. 20141036 ◽  
Author(s):  
Elisa Masi ◽  
Marzena Ciszak ◽  
Luisa Santopolo ◽  
Arcangela Frascella ◽  
Luciana Giovannetti ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Electrode Array ◽  
Bacterial Biofilms ◽  
Long Tail ◽  
New Frontier ◽  
Electrical Signalling ◽  
Spatio Temporal ◽  
Biofilm Development

In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we investigated electrical signalling as a possible driver in biofilm sociobiology. Using a multi-electrode array system that enables high spatio-temporal resolution, we studied the electrical activity in two biofilm-forming strains and one non-biofilm-forming strain. The action potential rates monitored during biofilm-forming bacterial growth exhibited a one-peak maximum with a long tail, corresponding to the highest biofilm development. This peak was not observed for the non-biofilm-forming strain, demonstrating that the intensity of the electrical activity was not linearly related to the bacterial density, but was instead correlated with biofilm formation. Results obtained indicate that the analysis of the spatio-temporal electrical activity of bacteria during biofilm formation can open a new frontier in the study of the emergence of collective microbial behaviour.

scholarly journals Periodicity of Cell Attachment Patterns during Escherichia coli Biofilm Development

2003 ◽  
Vol 185 (18) ◽  
pp. 5632-5638 ◽  
Author(s):  
Konstantin Agladze ◽  
Debra Jackson ◽  
Tony Romeo
Keyword(s):  
Escherichia Coli ◽  
Laminar Flow ◽  
Biofilm Formation ◽  
Cell Attachment ◽  
Bacterial Biofilms ◽  
Flow Conditions ◽  
Biofilm Development ◽  
Complex Architecture ◽  
Activator Inhibitor ◽  
Laminar Flow Conditions

ABSTRACT The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model.

scholarly journals Antimicrobial Peptides-Coated Stainless Steel for Fighting Biofilms Formation for Food and Medical Fields: Review of Literature

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1216
Author(s):  
Mayssane Hage ◽  
Hikmat Akoum ◽  
Nour-Eddine Chihib ◽  
Charafeddine Jama
Keyword(s):  
Stainless Steel ◽  
Antimicrobial Peptides ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Bacterial Biofilms ◽  
Food Environments ◽  
Review Of Literature ◽  
Safe Alternative ◽  
Antimicrobial Coatings ◽  
Biofilm Development

Emerging technology regarding antimicrobial coatings contributes to fighting the challenge of pathogenic bacterial biofilms in medical and agri-food environments. Stainless steel is a material widely used in those fields since it has satisfying mechanical properties, but it, unfortunately, lacks the required bio-functionality, rendering it vulnerable to bacterial adhesion and biofilm formation. Therefore, this review aims to present the coatings developed by employing biocides grafted on stainless steel. It also highlights antimicrobial peptides (AMPs)used to coat stainless steel, particularly nisin, which is commonly accepted as a safe alternative to prevent pathogenic biofilm development.

scholarly journals Solution-Mediated Modulation of Pseudomonas aeruginosa Biofilm Formation by a Cationic Synthetic Polymer

Antibiotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 61 ◽  
Author(s):  
Leanna L. Foster ◽  
Shin-ichi Yusa ◽  
Kenichi Kuroda
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Cationic Polymer ◽  
Growth Behavior ◽  
Bacterial Biofilms ◽  
Cationic Polymers ◽  
New Approach ◽  
Planktonic Bacteria ◽  
Biofilm Development ◽  
Biofilm Prevention

Bacterial biofilms and their associated infections are a continuing problem in the healthcare community. Previous approaches utilizing anti-biofilm coatings suffer from short lifetimes, and their applications are limited to surfaces. In this research, we explored a new approach to biofilm prevention based on the hypothesis that changing planktonic bacteria behavior to result in sub-optimal biofilm formation. The behavior of planktonic Pseudomonas aeruginosa exposed to a cationic polymer was characterized for changes in growth behavior and aggregation behavior, and linked to resulting P. aeruginosa biofilm formation, biomass, viability, and metabolic activity. The incubation of P. aeruginosa planktonic bacteria with a cationic polymer resulted in the aggregation of planktonic bacteria, and a reduction in biofilm development. We propose that cationic polymers may sequester planktonic bacteria away from surfaces, thereby preventing their attachment and suppressing biofilm formation.

scholarly journals The Enterococcus faecalis fsr Two-Component System Controls Biofilm Development through Production of Gelatinase

2004 ◽  
Vol 186 (17) ◽  
pp. 5629-5639 ◽  
Author(s):  
Lynn E. Hancock ◽  
Marta Perego
Keyword(s):  
Enterococcus Faecalis ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Heart Valves ◽  
Bacterial Resistance ◽  
Two Component System ◽  
Component System ◽  
Abiotic Surfaces ◽  
Two Component ◽  
Biofilm Development

ABSTRACT Bacterial growth as a biofilm on solid surfaces is strongly associated with the development of human infections. Biofilms on native heart valves (infective endocarditis) is a life-threatening disease as a consequence of bacterial resistance to antimicrobials in such a state. Enterococci have emerged as a cause of endocarditis and nosocomial infections despite being normal commensals of the gastrointestinal and female genital tracts. We examined the role of two-component signal transduction systems in biofilm formation by the Enterococcus faecalis V583 clinical isolate and identified the fsr regulatory locus as the sole two-component system affecting this unique mode of bacterial growth. Insertion mutations in the fsr operon affected biofilm formation on two distinct abiotic surfaces. Inactivation of the fsr-controlled gene gelE encoding the zinc-metalloprotease gelatinase was found to prevent biofilm formation, suggesting that this enzyme may present a unique target for therapeutic intervention in enterococcal endocarditis.

scholarly journals Novel Methods for Characterization of Paroxysmal Atrial Fibrillation in Human Left Atria

2013 ◽  
Vol 7 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Jichao Zhao ◽  
Yan Yao ◽  
Wen Huang ◽  
Rui Shi ◽  
Shu Zhang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Electrical Activity ◽  
Wave Front ◽  
Paroxysmal Atrial Fibrillation ◽  
High Frequency ◽  
Electrode Array ◽  
Accurate Identification ◽  
Spatio Temporal ◽  
Activation Pathways ◽  
Unipolar Electrograms

Introduction: More effective methods for characterizing 3D electrical activity in human left atrium (LA) are needed to identify substrates/triggers and microreentrant circuit for paroxysmal atrial fibrillation (PAF). We describe a novel wavelet-based approach and wave-front centroid tracking that have been used to reconstruct regional activation frequency and electrical activation pathways from non-contact multi-electrode array. Methods: Data from 13 patients acquired prior to ablation for PAF with a 64 electrode noncontact catheter positioned in the LA were analysed. Unipolar electrograms were reconstructed at 2048 locations across each LA endocardial surface. Weighted fine- and coarse-scale electrograms were constructed by wavelet decomposition and combined with peak detection to identify atrial fibrillation (AF) activation frequency and fractionated activity at each site. LA regions with upper quartile AF frequencies were identified for each patient. On the other hand, a wave-front centroid tracking approach was introduced for this first time to detect macro-reentrant circuit during PAF. Results: The results employing wavelet-based analysis on atrial unipolar electrograms are validated by the signals recorded simultaneously via the contacted ablation catheter and visually tracking the 3D spread of activation through the interest region. Multiple connected regions of high frequency electrical activity were seen; most often in left superior pulmonary vein (10/12), septum (9/12) and atrial roof (9/12), as well as the ridge (8/12). The wave-front centroid tracking approach detects a major macro circuit involving LPVs, PLA, atrial floor, MV, septum, atrial roof and ridge. The regions with high frequency by wave-front tracking are consistent with the results using wavelet approach and our clinical observations. Conclusions: The wavelet-based technique and wave-front centroid tracking approach provide a robust means of extracting spatio-temporal characteristics of PAF. The approach could facilitate accurate identification of pro-arrhythmic substrate and triggers, and therefore, to improve success rate of catheter ablation for AF.

Development and assessment of a high-throughput biofilm and biomass testing platform

2021 ◽  
Vol 30 (Sup7) ◽  
pp. S36-S46
Author(s):  
Hosan Kim ◽  
Matthew Aquino ◽  
Mina Izadjoo
Keyword(s):  
Growth Rate ◽  
High Throughput ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
High Throughput Screening ◽  
Bacterial Strains ◽  
Bacterial Growth Rate ◽  
Testing Platform ◽  
Biofilm Development

Objective: To develop and evaluate a simple platform technology for developing static biofilms in a 96-well microtitre plate for various downstream applications. The technology allows monitoring of growth rate, biofilm formation and quantifying biofilm biomass by using crystal violet (CV) and safranin O (SO) staining over seven-day time periods for pathogens including clinical isolates most commonly associated with hard-to-treat wound infections. Method: A total of 157 bacteria including Acinetobacter, Enterobacter, Klebsiella, Pseudomonas and Staphylococcus spp. were used in the study. Bacterial growth was measured at 600nm optical density (OD). Biofilm formation was monitored and assessed quantitatively with CV at 570nm and SO staining at 492nm for one-, two-, three- and seven-day incubation periods. Results: Bacterial growth rate and static biofilm biomass in the 96-well plates varied for various strains tested. Both CV and SO staining showed similar results in the biomass, with SO assay displaying more reproducible data throughout the study. Most of the strains were metabolically active even at the seven-day incubation period. Microbial adherences of all bacterial strains on the plastic surface was assessed with CV staining: 28 Acinetobacter, 17 Staphylococcus, 12 Pseudomonas and four Enterobacter strains were strong biofilm producers. Moderate biofilm-producing strains included 27 Staphylococcus, 14 Acinetobacter, eight Pseudomonas and three Enterobacter. Weak biofilm-producing strains included: 33 Staphylococcus, six Enterobacter, two Pseudomonas and one Acinetobacter. Only one Pseudomonas aeruginosa strain did not develop biofilm. Conclusion: Our results demonstrate the feasibility of using 96-well microtitre plates as a high-throughput platform for quantitative measurement and assessment of biofilm development over time. Studying microbial adherence or biofilm biomass generated on various surfaces using a high-throughput system could provide valuable information for in vitro testing and developing therapeutics for biofilm infections. Employing the biofilm testing platform described in this study makes it possible to simultaneously develop different biofilms formed by specific pathogens, and study potential association between the quantity of bacterial biomass and strength of a biofilm formed by specific wound pathogens. In addition, the described testing approach could provide an optimal model for standardised and high-throughput screening of candidate antibiofilm therapeutics.

scholarly journals Escherichia coli Biofilms Have an Organized and Complex Extracellular Matrix Structure

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Chia Hung ◽  
Yizhou Zhou ◽  
Jerome S. Pinkner ◽  
Karen W. Dodson ◽  
Jan R. Crowley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Extracellular Matrix ◽  
Biofilm Formation ◽  
Developmental Stages ◽  
Three Dimensional ◽  
Bacterial Biofilms ◽  
Content Type ◽  
Abiotic Surfaces ◽  
Biochemical Analyses ◽  
Biofilm Development

ABSTRACTBacterial biofilms are ubiquitous in nature, and their resilience is derived in part from a complex extracellular matrix that can be tailored to meet environmental demands. Although common developmental stages leading to biofilm formation have been described, how the extracellular components are organized to allow three-dimensional biofilm development is not well understood. Here we show that uropathogenicEscherichia coli(UPEC) strains produce a biofilm with a highly ordered and complex extracellular matrix (ECM). We used electron microscopy (EM) techniques to image floating biofilms (pellicles) formed by UPEC. EM revealed intricately constructed substructures within the ECM that encase individual, spatially segregated bacteria with a distinctive morphology. Mutational and biochemical analyses of these biofilms confirmed curli as a major matrix component and revealed important roles for cellulose, flagella, and type 1 pili in pellicle integrity and ECM infrastructure. Collectively, the findings of this study elucidated that UPEC pellicles have a highly organized ultrastructure that varies spatially across the multicellular community.IMPORTANCEBacteria can form biofilms in diverse niches, including abiotic surfaces, living cells, and at the air-liquid interface of liquid media. Encasing these cellular communities is a self-produced extracellular matrix (ECM) that can be composed of proteins, polysaccharides, and nucleic acids. The ECM protects biofilm bacteria from environmental insults and also makes the dissolution of biofilms very challenging. As a result, formation of biofilms within humans (during infection) or on industrial material (such as water pipes) has detrimental and costly effects. In order to combat bacterial biofilms, a better understanding of components required for biofilm formation and the ECM is required. This study defined the ECM composition and architecture of floating pellicle biofilms formed byEscherichia coli.

scholarly journals Surfactants Efficiency on Pentachlophenol Contaminated Wastewater Enhanced by Pseudomonas Putida AJ 785569

2021 ◽  
Author(s):  
rim werheni Ammeri ◽  
yassin hidri ◽  
WAFA HASSRN ◽  
ines mehri ◽  
Nesrine khelifi ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Tween 80 ◽  
Bacterial Cells ◽  
A Value ◽  
Biofilm Development

Abstract This study has objectives to assess the effects of some surfactants on (1) the bacterial growth, (2) PCP (800 mgL -1 ) rate removal, and at last (3) biofilm development. Three different surfactants are used in this case as anionic (SDS), no anionic Tween 80 (TW80) and cationic (CTAB). The results improve that there was an adsorption of PCP by the bacterial cells of around 30 mg . L -1 and PCP removal of around 720 mgL -1 after seven days. It appeared that the surfactant adding affected the bacterial growth and reach a maximum of PCP removal with SDS addition with a value 676.66 mg L -1 in S.WW then CTAB and TW80. Biofilm formation in BHI with PCP showed a clear acceleration and enhancement of this activity with SDS addition. Besides, biofilm morphotype of selected strain appeared affected in form, density, and colour after different situations of stress caused by various surfactants or PCP.

Spatio-temporal formation of biofilms and extracellular matrix analysis in Azospirillum brasilense

2020 ◽  
Vol 367 (4) ◽  
Author(s):  
Víctor I Viruega-Góngora ◽  
Iris S Acatitla-Jácome ◽  
Sandra R Reyes-Carmona ◽  
Beatriz E Baca ◽  
Alberto Ramírez-Mata
Keyword(s):  
Extracellular Matrix ◽  
Biofilm Formation ◽  
Azospirillum Brasilense ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Polar Flagellum ◽  
Matrix Components ◽  
Spatio Temporal ◽  
Biofilm Development ◽  
Biofilm Matrix

ABSTRACT Elucidation of biofilm structure formation in the plant growth-promoting rhizobacterium Azospirillum brasilense is necessary to gain a better understanding of the growth of cells within the extracellular matrix and its role in the colonization of plants of agronomic importance. We used immunofluorescence microscopy and confocal laser scanning microscopy to study spatio-temporal biofilm formation on an abiotic surface. Observations facilitated by fluorescence microscopy revealed the presence of polar flagellin, exopolysaccharides, outer major membrane protein (OmaA) and extracellular DNA in the Azospirillum biofilm matrix. In static culture conditions, the polar flagellum disaggregated after 3 days of biofilm growth, but exopolysaccharides were increasing. These findings suggest that the first step in biofilm formation may be attachment, in which the bacterium first makes contact with a surface through its polar flagellum. After attaching to the surface, the long flagella and OmaA intertwine the cells to form a network. These bacterial aggregates initiate biofilm development. The underlying mechanisms dictating how the biofilm matrix components of A. brasilense direct the overall morphology of the biofilm are not well known. The methods developed here might be useful in further studies that analyze the differential spatial regulation of genes encoding matrix components that drive biofilm construction.

scholarly journals Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver

2021 ◽  
Vol 22 (3) ◽  
pp. 1060
Author(s):  
Erik Gerner ◽  
Sofia Almqvist ◽  
Peter Thomsen ◽  
Maria Werthén ◽  
Margarita Trobos
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Sodium Salicylate ◽  
Treatment Strategies ◽  
Cell Aggregation ◽  
Wound Fluid ◽  
Global Challenge ◽  
3D Collagen ◽  
Biofilm Development ◽  
Biofilm Structure

Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.

Sign in / Sign up

Export Citation Format

Share Document