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Biofilm matrix

About: Biofilm matrix is a research topic. Over the lifetime, 1589 publications have been published within this topic receiving 110140 citations.


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Journal ArticleDOI
TL;DR: In this article, the alternating nonnegative least squares (ANLS) approach was incorporated with the sequential coordinate-wise descent (SCD) algorithm to realize the NMF analysis for the large-scale hyperspectral data set.
Abstract: Biofilms are microbial aggregates of microorganisms surrounded by a hydrogel-like matrix formed by extracellular polymeric substances (EPS). The formation of biofilms is intrinsically complex, from the attachment of microbial cells to the dispersion of the biofilm. Meanwhile, the three-dimensional framework built up by EPS changes with time and protects the microorganisms against environmental stress. Simultaneously acquiring chemical and structural information within the biofilm matrix is vital for the cognition and regulation of biofilms, yet it remains a great challenge due to the sample complexity and the limited approaches. In this study, confocal Raman microscopy and non-negative matrix factorization (NMF) analysis were combined to investigate spatiotemporal organization of Escherichia coli biofilms during development at molecular-level detail. The alternating non-negative least-squares (ANLS) approach was incorporated with the sequential coordinate-wise descent (SCD) algorithm to realize the NMF analysis for the large-scale hyperspectral data set. As a result, three components, including bacteria, protein, and polyhydroxybutyrate (PHB), were successfully resolved from the spectra of E. coli biofilm. Furthermore, the structural changes of biofilms could be visualized and quantified by their abundances derived from the NMF analysis, which might be related to the nutrient and oxygen gradient and physiological functions. This methodology provides a comprehensive understanding of the chemical constituents and their spatiotemporal distribution within the biofilm matrix. Furthermore, it also shows great potential for the analysis of unknown and complex biological samples with 3D Raman mapping.

21 citations

Journal ArticleDOI
TL;DR: In this paper, Salicylic acid (SAL) has been shown to induce biofilm formation in Staphylococcus aureus and to affect the expression of virulence factors.
Abstract: Salicylic acid (SAL) has recently been shown to induce biofilm formation in Staphylococcus aureus and to affect the expression of virulence factors This study was aimed to investigate the effect of SAL on the regulatory agr system and its impact on S aureus biofilm formation The agr quorum-sensing system, which is a central regulator in S aureus pathogenicity, plays a pivotal role in the dispersal of S aureus mature biofilms and contributes to the creation of new colonization sites Here, we demonstrate that SAL impairs biofilm dispersal by interfering with agr expression As revealed by our work, protease and surfactant molecule production is diminished, and bacterial cell autolysis is also negatively affected by SAL Furthermore, as a consequence of SAL treatment, the S aureus biofilm matrix revealed the lack of extracellular DNA In silico docking and simulation of molecular dynamics provided evidence for a potential interaction of AgrA and SAL, resulting in reduced activity of the agr system In conclusion, SAL stabilized the mature S aureus biofilms, which may prevent bacterial cell dissemination However, it may foster the establishment of infections locally and consequently increase bacterial persistence leading to therapeutic failure

21 citations

Journal ArticleDOI
TL;DR: This study demonstrates the efficacy, feasibility, and safety of using heat as an adjuvant treatment for infected hemodialysis catheters, and shows that treating with heat in the presence of antibiotics led to additive killing of Staphylococcus epidermidis with similar trends seen for Staphyllococcus aureus and Klebsiella pneumoniae.
Abstract: Central line-associated bloodstream infections (CLABSIs) are not easily treated, and many catheters (e.g., hemodialysis catheters) are not easily replaced. Biofilms (the source of infection) on catheter surfaces are notoriously difficult to eradicate. We have recently demonstrated that modest elevations of temperature lead to increased staphylococcal susceptibility to vancomycin and significantly soften the biofilm matrix. In this study, using a combination of microbiological, computational, and experimental studies, we demonstrate the efficacy, feasibility, and safety of using heat as an adjuvant treatment for infected hemodialysis catheters. Specifically, we show that treating with heat in the presence of antibiotics led to additive killing of Staphylococcus epidermidis with similar trends seen for Staphylococcus aureus and Klebsiella pneumoniae. The magnitude of temperature elevation required is relatively modest (45-50°C) and similar to that used as an adjuvant to traditional cancer therapy. Using a custom-designed benchtop model of a hemodialysis catheter, positioned with tip in the human vena cava as well as computational fluid dynamic simulations, we demonstrate that these temperature elevations are likely achievable in situ with minimal increased in overall blood temperature.

21 citations

Journal ArticleDOI
TL;DR: The data reveal an important role of extracellular aminopeptidase in biofilm development, suggesting PaAP as a therapeutic target for preventing P. aeruginosa infection and combating biofilm-related complications.
Abstract: Biofilm bacteria are embedded within a self-secreted extracellular matrix that contains a considerable amount of proteins including many extracellular enzymes. However, little is known about the roles of such enzymes in biofilm development. Here, we studied Pseudomonas aeruginosa aminopeptidase (PaAP, encoded by PA2939 that we named the gene as paaP in this study), a quorum-sensing-regulated enzyme and one of the most abundant extracellular proteins in the biofilm matrix of this opportunistic pathogen and environmental bacterium. We found that deletion of paaP in P. aeruginosa increased initial attachment and biofilm formation at early stages of biofilm development. After 24 h growth, loss of PaAP resulted in substantial cell death and biofilm disruption. Bacterial cell death was independent of biofilm matrix polysaccharide Psl, while biofilm disruption was due to the degradation of Psl matrix by dead-bacteria-released glycosyl hydrolase PslG, thereby leading to biofilm dispersion. PaAP functioned extracellularly and aminopeptidase catalytic activity was essential for its effect on biofilm development. Our data reveal an important role of extracellular aminopeptidase in biofilm development, suggesting PaAP as a therapeutic target for preventing P. aeruginosa infection and combating biofilm-related complications.

21 citations

Book ChapterDOI
01 Jan 2004
TL;DR: It has been reported that Candida albicans biofilms are up to 4,000 times more resistant to fluconazole compared with planktonic, free-floating cells.
Abstract: Biofilms are a primitive type of developmental biology in which spatial organization of the cells within the matrix optimizes the utilization of the nutritional resources available; they incorporate an immobilized enzyme system in which the millieu and the enzyme activities are constantly changing and evolving to the appropriate steady state. The biomaterial properties affecting initial adhesion range from chemical properties to hydrophobicity to surface roughness. Since these biomedical devices are usually surrounded by body fluids, such as urine, blood, saliva, and synovial fluid, their surfaces often acquire a glycoproteinaceous conditioning film following implantation. For short-term urinary catheterization, up to 50% of the patients develop an associated urinary tract infection (UTI), but almost all patients undergoing long-term catheterization ultimately became infected with associated device colonization organisms. Several groups have demonstrated that the Candida biofilm lifestyle leads to dramatically increased levels of resistance to the most commonly used antifungal agents, fluconazole and amphotericin B. Different mechanisms may be responsible for the intrinsic resistance of Candida biofilms. These include: (i) effects of the biofilm matrix on penetration of drugs, (ii) decreased growth rate and nutrient limitation, (iii) expression of resistance genes, particularly those encoding efflux pumps, and (iv) presence of “persister” cells. It has been reported that Candida albicans biofilms are up to 4,000 times more resistant to fluconazole compared with planktonic, free-floating cells.

21 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021138
2020189
2019157
2018121
2017113