scholarly journals Amyloid Structures as Biofilm Matrix Scaffolds

2016 ◽  
Vol 198 (19) ◽  
pp. 2579-2588 ◽  
Author(s):  
Agustina Taglialegna ◽  
Iñigo Lasa ◽  
Jaione Valle
Keyword(s):  
Paradigm Shift ◽  
Bacterial Biofilm ◽  
Extracellular Dna ◽  
Host Immune System ◽  
Biotechnological Applications ◽  
Amyloid Fibers ◽  
Gram Positive Bacteria ◽  
Recent Developments ◽  
Block Structures ◽  
Biofilm Matrix

Recent insights into bacterial biofilm matrix structures have induced a paradigm shift toward the recognition of amyloid fibers as common building block structures that confer stability to the exopolysaccharide matrix. Here we describe the functional amyloid systems related to biofilm matrix formation in both Gram-negative and Gram-positive bacteria and recent knowledge regarding the interaction of amyloids with other biofilm matrix components such as extracellular DNA (eDNA) and the host immune system. In addition, we summarize the efforts to identify compounds that target amyloid fibers for therapeutic purposes and recent developments that take advantage of the amyloid structure to engineer amyloid fibers of bacterial biofilm matrices for biotechnological applications.

scholarly journals Role of Extracellular DNA in Initial Bacterial Adhesion and Surface Aggregation

2010 ◽  
Vol 76 (10) ◽  
pp. 3405-3408 ◽  
Author(s):  
Theerthankar Das ◽  
Prashant K. Sharma ◽  
Henk J. Busscher ◽  
Henny C. van der Mei ◽  
Bastiaan P. Krom
Keyword(s):  
Bacterial Adhesion ◽  
Extracellular Dna ◽  
Acid Base ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Initial Adhesion ◽  
Biofilm Matrix

ABSTRACT Extracellular DNA (eDNA) is an important component of the biofilm matrix. We show that removal of eDNA from Gram-positive bacteria reduces initial adhesion to and aggregation of bacteria on surfaces. Thermodynamic analyses indicated that eDNA introduces favorable acid-base interactions, explaining the effect of eDNA on aggregation and adhesion to the surface.

scholarly journals Z-form extracellular DNA is a structural component of the bacterial biofilm matrix

Cell ◽  
2021 ◽  
Author(s):  
John R. Buzzo ◽  
Aishwarya Devaraj ◽  
Erin S. Gloag ◽  
Joseph A. Jurcisek ◽  
Frank Robledo-Avila ◽  
...  
Keyword(s):  
Structural Component ◽  
Bacterial Biofilm ◽  
Extracellular Dna ◽  
Biofilm Matrix

scholarly journals Extracellular DNA (eDNA). A Major Ubiquitous Element of the Bacterial Biofilm Architecture

2021 ◽  
Vol 22 (16) ◽  
pp. 9100
Author(s):  
Davide Campoccia ◽  
Lucio Montanaro ◽  
Carla Renata Arciola
Keyword(s):  
Bacterial Biofilm ◽  
Extracellular Dna ◽  
Bacterial Biofilms ◽  
Special Focus ◽  
Review Of The Literature ◽  
Scientific Interest ◽  
Biofilm Architecture ◽  
Complex Architecture ◽  
Molecular Components ◽  
Biofilm Matrix

After the first ancient studies on microbial slime (the name by which the biofilm matrix was initially indicated), multitudes of studies on the morphology, composition and physiology of biofilms have arisen. The emergence of the role that biofilms play in the pathogenesis of recalcitrant and persistent clinical infections, such as periprosthetic orthopedic infections, has reinforced scientific interest. Extracellular DNA (eDNA) is a recently uncovered component that is proving to be almost omnipresent in the extracellular polymeric substance (EPS) of biofilm. This macromolecule is eliciting unprecedented consideration for the critical impact on the pathogenesis of chronic clinical infections. After a systematic review of the literature, an updated description of eDNA in biofilms is presented, with a special focus on the latest findings regarding its fundamental structural role and the contribution it makes to the complex architecture of bacterial biofilms through interactions with a variety of other molecular components of the biofilm matrix.

scholarly journals RpiRc regulates RsbU to modulate eDNA-dependent biofilm formation and in vivo virulence of Staphylococcus aureus in a mouse model of catheter infection

2019 ◽  
Author(s):  
Adrien Fischer ◽  
Myriam Girard ◽  
Floriane Laumay ◽  
Anne-Kathrin Woischnig ◽  
Nina Khanna ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mouse Model ◽  
Biofilm Formation ◽  
Ex Vivo ◽  
Bacterial Biofilm ◽  
Extracellular Dna ◽  
Hek293 Cells ◽  
Catheter Infection ◽  
Biofilm Matrix

AbstractStaphylococcus aureus is a major human pathogen. Despite high incidence and morbidity, molecular mechanisms occurring during infection remain largely unknown. Under defined conditions, biofilm formation contributes to the severity of S. aureus related infections. Extracellular DNA (eDNA), a component of biofilm matrix released from apoptotic bacteria, is involved in biofilm structure and stability. In many bacterial biofilms, eDNA originates from cell lysis although eDNA can also be actively secreted or exported by bacterial membrane vesicles. By screening the Nebraska transposon library, we identified rpiRc as a biofilm regulator involved in eDNA regulation. RpiRc is a transcription factor from the pentose phosphate pathway (PPP) whose product is a polysaccharide intercellular adhesin (PIA) precursor. However, rpiRc mutant strain showed neither susceptibility to DispersinB® (a commercially available enzyme disrupting PIA biofilms) nor alteration of ica transcription (the operon regulating PIA production). Decreased biofilm formation was linked to Sln, an extracellular compound degrading eDNA in an autolysis independent pathway. Biofilm susceptibility to antibiotics in wt and mutant strains was tested using a similar protocol as the Calgary biofilm device. Involvement of RpiRc in S. aureus virulence was assessed ex vivo by internalization experiments into HEK293 cells and in vivo in a mouse model of subcutaneous catheter infection. While minimum inhibitory concentrations (MICs) of planktonic cells were not affected in the mutant strain, we observed increased biofilm susceptibility to almost all tested antibiotics, regardless of their mode of action. More importantly, the rpiRc mutant showed reduced virulence in both ex vivo and in vivo experiments related to decreased fnbpA-B transcription and eDNA production. RpiRc is an important regulator involved in eDNA degradation inside the matrix of mature PIA independent biofilms. These results illustrate that RpiRc contributes to increased antibiotic tolerance in mature bacterial biofilm and also to S. aureus cell adhesion and virulence during subcutaneous infection.Author summaryBiofilm formation contributes to the severity of Staphylococcus aureus related infections. Biofilm matrix is mainly composed by polysaccharide intercellular adhesion (PIA), proteins and extracellular DNA (eDNA). By screening a mutant library of S. aureus, RpiRc was identified as a new regulator of eDNA dependent biofilm formation. How RpiRc regulates biofilm and its role in S. aureus virulence was studied in four different S. aureus strains. Deletion of RpiRc resulted in a pronounced decreased eDNA dependent biofilm formation, but not PIA dependent biofilm formation. Decreased biofilm formation was not related to increased autolysis, but was linked to extracellular compounds found in the supernatant of mutant biofilms. Sln was identified as one of this compound. RpiRc deletion also decreased biofilm recalcitrance (resistance) to selected antibiotics. Involvement of RpiRc in S. aureus pathogenesis was investigated ex vivo by internalization into HEK293 cells and in vivo in a mouse model of catheter infection. RpiRc deletion resulted in decreased virulence related to decreased expression of surface proteins like the fibronectin binding proteins A and B (FnbpA-B). These results illustrate that RpiRc contributes to increased antibiotic tolerance in mature bacterial biofilm and also to S. aureus cell adhesion and virulence during subcutaneous infection.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

scholarly journals Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence

2018 ◽  
Vol 11 (3) ◽  
pp. 227-241 ◽  
Author(s):  
Olivier Lesouhaitier ◽  
Thomas Clamens ◽  
Thibaut Rosay ◽  
Florie Desriac ◽  
Mélissande Louis ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Critical Problem ◽  
Resistant Variant ◽  
Bacterial Physiology ◽  
Gram Positive Bacteria ◽  
Biofilm Production ◽  
The Impact ◽  
Original Approach ◽  
Antibacterial Potential

Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.

scholarly journals Usnic Acid, a Natural Antimicrobial Agent Able To Inhibit Bacterial Biofilm Formation on Polymer Surfaces

2004 ◽  
Vol 48 (11) ◽  
pp. 4360-4365 ◽  
Author(s):  
I. Francolini ◽  
P. Norris ◽  
A. Piozzi ◽  
G. Donelli ◽  
P. Stoodley
Keyword(s):  
Biofilm Formation ◽  
Usnic Acid ◽  
Modern Medicine ◽  
The Body ◽  
Bacterial Biofilm ◽  
Polymer Surfaces ◽  
Gram Positive Bacteria ◽  
The Status ◽  
Bacteria And Fungi ◽  
Systemic Infections

ABSTRACT In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways.

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