scholarly journals Deciphering Streptococcal Biofilms

2020 ◽  
Vol 8 (11) ◽  
pp. 1835
Author(s):  
Puja Yadav ◽  
Shalini Verma ◽  
Richard Bauer ◽  
Monika Kumari ◽  
Meenakshi Dua ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Biofilm Formation ◽  
Expression Patterns ◽  
Initial Step ◽  
Molecular Techniques ◽  
Surface Proteins ◽  
Considerable Proportion ◽  
Bacterial Cells ◽  
Bacterial Survival ◽  
Biofilm Growth

Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.

Bioinspired surfaces to delay biofilm formation: different surfaces with different mechanisms

2020 ◽  
Author(s):  
Jinju Chen
Keyword(s):  
Contact Angle ◽  
Biofilm Formation ◽  
Early Stage ◽  
Contact Angle Hysteresis ◽  
Antibacterial Properties ◽  
Hierarchical Structures ◽  
Bacterial Cells ◽  
Biofilm Growth ◽  
Porous Surfaces ◽  
Rose Petal

<p>Biofilm associated infections are the fourth leading cause of death worldwide, within the U.S. about 2 million annual cases lead to more than $5 billion USD in added medical costs per annum. Therefore, it is important to control biofilm growth and reduce the instances of infections.  Physical strategies, in particular the use of rationally designed surface topographies or surface energies, have present us with an interesting approach to prevent bacterial adherence and biofilm growth without the requirement for antimicrobials.</p> <p>A variety of natural surfaces exhibit antibacterial properties. Examples of such surfaces include rose petals with hierarchical structures and Nepenthes pitcher plants with slippery liquid-infused porous surfaces.  </p> <p>In this study, we fabricated different  biomimetic surfaces (rose-petal surfaces and slippery liquid-infused porous surfaces).   We have demonstrated that rose-petal surface can delay early stage P. aeruginosa and S. epidermidis biofilms formation (2 days) by about 70% and control  biofilm  formation according to surface structures.  The mechanisms of hierarchical structures  of rose-petal influence biofilm formation are two folds: 1) Papillae microstructure block  the bacterial clusters in between the valleys, limiting the potential for cell-cell communication via fibrous networks, thereby resulting in impaired biofilm growth. 2) The secondary structure (nano-folds) on microstructures can align bacterial cells within the constrained grooves, thereby delaying cell clusters formation during short term growth of biofilm.</p> <p>While, the slippery liquid-infused porous surface(s) can prevent over 90% P. aeruginosa and S. epidermidis biofilms formation for a duration of 6 days.  These are mainly attributed to their high contact angle and extreme low contact angle hysteresis.</p>

scholarly journals Effects ofBacillusSerine Proteases on the Bacterial Biofilms

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Olga Mitrofanova ◽  
Ayslu Mardanova ◽  
Vladimir Evtugyn ◽  
Lydia Bogomolnaya ◽  
Margarita Sharipova
Keyword(s):  
Biofilm Formation ◽  
Quantitative Methods ◽  
Time Course ◽  
Extracellular Polymeric Substances ◽  
Proteolytic Enzymes ◽  
Opportunistic Pathogen ◽  
Glutamyl Endopeptidase ◽  
Bacterial Cells ◽  
Biofilm Growth ◽  
Tract Infections

Serratia marcescensis an emerging opportunistic pathogen responsible for many hospital-acquired infections including catheter-associated bacteremia and urinary tract and respiratory tract infections. Biofilm formation is one of the mechanisms employed byS. marcescensto increase its virulence and pathogenicity. Here, we have investigated the main steps of the biofilm formation byS. marcescensSR 41-8000. It was found that the biofilm growth is stimulated by the nutrient-rich environment. The time-course experiments showed thatS. marcescenscells adhere to the surface of the catheter and start to produce extracellular polymeric substances (EPS) within the first 2 days of growth. After 7 days,S. marcescensbiofilms maturate and consist of bacterial cells embedded in a self-produced matrix of hydrated EPS. In this study, the effect ofBacillus pumilus3-19 proteolytic enzymes on the structure of 7-day-oldS. marcescensbiofilms was examined. Using quantitative methods and scanning electron microscopy for the detection of biofilm, we demonstrated a high efficacy of subtilisin-like protease and glutamyl endopeptidase in biofilm removal. Enzymatic treatment resulted in the degradation of the EPS components and significant eradication of the biofilms.

scholarly journals Visible Light-Activated Carbon Dots for Inhibiting Biofilm Formation and Inactivating Biofilm-Associated Bacterial Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiuli Dong ◽  
Christopher M. Overton ◽  
Yongan Tang ◽  
Jasmine P. Darby ◽  
Ya-Ping Sun ◽  
...  
Keyword(s):  
Visible Light ◽  
Carbon Dots ◽  
Biofilm Formation ◽  
Chelating Agents ◽  
Early Stage ◽  
Inhibitory Effect ◽  
Bacterial Cells ◽  
Planktonic Cells ◽  
Biofilm Growth ◽  
Time Point

This study aimed to address the significant problems of bacterial biofilms found in medical fields and many industries. It explores the potential of classic photoactive carbon dots (CDots), with 2,2′-(ethylenedioxy)bis (ethylamine) (EDA) for dot surface functionalization (thus, EDA-CDots) for their inhibitory effect on B. subtilis biofilm formation and the inactivation of B. subtilis cells within established biofilm. The EDA-CDots were synthesized by chemical functionalization of selected small carbon nanoparticles with EDA molecules in amidation reactions. The inhibitory efficacy of CDots with visible light against biofilm formation was dependent significantly on the time point when CDots were added; the earlier the CDots were added, the better the inhibitory effect on the biofilm formation. The evaluation of antibacterial action of light-activated EDA-CDots against planktonic B. subtilis cells versus the cells in biofilm indicate that CDots are highly effective for inactivating planktonic cells but barely inactivate cells in established biofilms. However, when coupling with chelating agents (e.g., EDTA) to target the biofilm architecture by breaking or weakening the EPS protection, much enhanced photoinactivation of biofilm-associated cells by CDots was achieved. The study demonstrates the potential of CDots to prevent the initiation of biofilm formation and to inhibit biofilm growth at an early stage. Strategic combination treatment could enhance the effectiveness of photoinactivation by CDots to biofilm-associated cells.

scholarly journals Changes in the Expression of Biofilm-Associated Surface Proteins inStaphylococcus aureusFood-Environmental Isolates Subjected to Sublethal Concentrations of Disinfectants

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Lenka Cincarova ◽  
Ondrej Polansky ◽  
Vladimir Babak ◽  
Pavel Kulich ◽  
Petr Kralik
Keyword(s):  
Biofilm Formation ◽  
Protein A ◽  
Surface Proteins ◽  
Bacterial Cells ◽  
Abiotic Surfaces ◽  
Immunoglobulin Binding Protein ◽  
Chloramine T ◽  
Nucleic Acid Stain ◽  
Immunoglobulin Binding ◽  
Sublethal Concentrations

Sublethal concentrations (sub-MICs) of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on threeStaphylococcus aureusbiofilm formers (strong B+++, moderate B++, and weak B+) that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25–2.5% ethanol and 2500 μg/mL chloramine T significantly enhancedS. aureusbiofilm formation. To visualize differences in biofilm compactness betweenS. aureusbiofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.

scholarly journals Transcriptome Sequencing Reveals Wide Expression Reprogramming of Basal and Unknown Genes in Leptospira biflexa Biofilms

mSphere ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Gregorio Iraola ◽  
Lucía Spangenberg ◽  
Bruno Lopes Bastos ◽  
Martín Graña ◽  
Larissa Vasconcelos ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Biofilm Formation ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Environmental Water ◽  
Pathogenic Species ◽  
Rna Seq ◽  
Biofilm Growth ◽  
Complete Life Cycle ◽  
Transcriptional Changes

ABSTRACT In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis. The genus Leptospira is composed of pathogenic and saprophytic spirochetes. Pathogenic Leptospira is the etiological agent of leptospirosis, a globally spread neglected disease. A key ecological feature of some pathogenic species is their ability to survive both within and outside the host. For most leptospires, the ability to persist outside the host is associated with biofilm formation, a most important bacterial strategy to face and overcome hostile environmental conditions. The architecture and biochemistry of leptospiral biofilms are rather well understood; however, the genetic program underpinning biofilm formation remains mostly unknown. In this work, we used the saprophyte Leptospira biflexa as a model organism to assess over- and underrepresented transcripts during the biofilm state, using transcriptome sequencing (RNA-seq) technology. Our results showed that some basal biological processes like DNA replication and cell division are downregulated in the mature biofilm. Additionally, we identified significant expression reprogramming for genes involved in motility, sugar/lipid metabolism, and iron scavenging, as well as for outer membrane-encoding genes. A careful manual annotation process allowed us to assign molecular functions to many previously uncharacterized genes that are probably involved in biofilm metabolism. We also provided evidence for the presence of small regulatory RNAs in this species. Finally, coexpression networks were reconstructed to pinpoint functionally related gene clusters that may explain how biofilm maintenance is regulated. Beyond elucidating some genetic aspects of biofilm formation, this work reveals a number of pathways whose functional dissection may impact our understanding of leptospiral biology, in particular how these organisms adapt to environmental changes. IMPORTANCE In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis.

scholarly journals Low-Field Nuclear Magnetic Resonance Characteristics of Biofilm Development Process

2021 ◽  
Vol 9 (12) ◽  
pp. 2466
Author(s):  
Yajun Zhang ◽  
Yusheng Lin ◽  
Xin Lv ◽  
Aoshu Xu ◽  
Caihui Feng ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Biofilm Formation ◽  
Development Process ◽  
Bacterial Cells ◽  
T2 Relaxation ◽  
Biofilm Growth ◽  
Low Field ◽  
Biofilm Development ◽  
Nuclear Magnetic

To in situ and noninvasively monitor the biofilm development process by low-field nuclear magnetic resonance (NMR), experiments should be made to determine the mechanisms responsible for the T2 signals of biofilm growth. In this paper, biofilms were cultivated in both fluid media and saturated porous media. T2 relaxation for each sample was measured to investigate the contribution of the related processes to T2 relaxation signals. In addition, OD values of bacterial cell suspensions were measured to provide the relative number of bacterial cells. We also obtained SEM photos of the biofilms after vacuum freeze-drying the pure sand and the sand with biofilm formation to confirm the space within the biofilm matrix and identify the existence of biofilm formation. The T2 relaxation distribution is strongly dependent on the density of the bacterial cells suspended in the fluid and the stage of biofilm development. The peak time and the peak percentage can be used as indicators of the biofilm growth states.

scholarly journals Comparison between a Conventional Anti-Biofouling Compound and a Novel Modified Low-Fouling Polyethersulfone Ultrafiltration Membrane: Bacterial Anti-Attachment, Water Quality and Productivity

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 227
Author(s):  
Norhan Nady ◽  
Noha Salem ◽  
Ranya Amer ◽  
Ahmed El-Shazly ◽  
Sherif H. Kandil ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Water Productivity ◽  
Initial Step ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Bacterial Regrowth ◽  
Membrane Surfaces ◽  
Membrane Biofouling ◽  
Modified Membrane

In this work, the efficiency of a conventional chlorination pretreatment is compared with a novel modified low-fouling polyethersulfone (PES) ultrafiltration (UF) membrane, in terms of bacteria attachment and membrane biofouling reduction. This study highlights the use of membrane modification as an effective strategy to reduce bacterial attachment, which is the initial step of biofilm formation, rather than using antimicrobial agents that can enhance bacterial regrowth. The obtained results revealed that the filtration of pretreated, inoculated seawater using the modified PES UF membrane without the pre-chlorination step maintained the highest initial flux (3.27 ± 0.13 m3·m−2·h−1) in the membrane, as well as having one and a half times higher water productivity than the unmodified membrane. The highest removal of bacterial cells was achieved by the modified membrane without chlorination, in which about 12.07 × 104 and 8.9 × 104 colony-forming unit (CFU) m−2 bacterial cells were retained on the unmodified and modified membrane surfaces, respectively, while 29.4 × 106 and 0.42 × 106 CFU mL−1 reached the filtrate for the unmodified and modified membranes, respectively. The use of chlorine disinfectant resulted in significant bacterial regrowth.

scholarly journals Formation of biofilms by representatives of the oral microflora on the surfaces of basic materials

2021 ◽  
Vol 23 (4) ◽  
pp. 547-554
Author(s):  
S. M. Rozhko ◽  
R. V. Kutsyk ◽  
I. V. Paliichuk
Keyword(s):  
Biofilm Formation ◽  
Gentian Violet ◽  
Brain Heart Infusion ◽  
P Value ◽  
Total Biomass ◽  
Microbiological Analysis ◽  
Bacterial Cells ◽  
Biofilm Growth ◽  
Oral Microflora ◽  
Glass Slides

The aim of the work is to conduct a comparative analysis of the biofilm formation by representatives of the oral microflora on the surfaces of basic materials. Materials and methods. The process of biofilm formation was examined on 7 types of basic plastic samples: Polyan, Breflex, Nylon, Protakryl, Vinakryl, Biocryl, which were used for the manufacture of removable prosthetic basis constructions, and SYNMA, which was used for comparison. Biofilm formation was analyzed by the method Y. Zhang (2017) with minor modifications. The test sample was placed in a test tube with 2.0 ml of nutrient broth Brain Heart Infusion to model the biofilm growth of microorganisms (HiMedia Laboratories Pvt. Ltd., India) supplemented with 1 % glucose, pre-inoculated with test strains at a final concentration of 1 × 104 CFU/ml. The strains were cultivated for 24 hours at a temperature of 37 °C under continuous stirring in a shaker MR-1 (SIA BIOS AN, Latvia) at 20 rpm. Evaluation of the biofilm massiveness was performed after gentian violet staining followed by elution of the stain with ethanol and registration of the eluent optical density (OD). The OD was measured with a Synergy™ HTX S1LFTA microplate multimode photometer (BioTek Instruments, Inc., USA) at 595 nm wavelength using Gen5™ Data Analysis Software. The number of viable bacterial cells in the formed biofilms was determined by the method of ten-fold serial dilutions. The obtained results were converted per unit area of the sample tested. Processing of the results was performed using a two-sample t-test with the software package Statistica 13.0 and Microsoft Office Excel, the differences were considered statistically significant at a P value of < 0.05. Statistical analysis of the obtained data was presented as mean values of measurements ± standard deviation for three independent experiments. Results. According to the microbiological analysis results it was found that α-hemolytic streptococci S. oralis and S. sanguinis showed the ability to form biofilms on the surfaces of basic materials, namely Protacryl and Vinacryl, the total biomass of S. sanguinis biofilms was 47.7 % (P < 0.01) and 14.7 % (P > 0.05) greater, respectively, in comparison to a glass slide. Inhibition of biofilm formation processes was observed on the surfaces of Nylon and Biocryl basic materials. S. oralis and S. gordonii showed the highest ability to survive in biofilms. The intensity of C. albicans biofilms formation on Biocryl basic materials, comparative plastics SINMA and Breflex basic materials was greater than on glass slides by 48.3 %, 43.0 % and 34.9 % (P < 0.01), respectively. The least massive C. albicans biofilms were formed on Breflex surfaces and SINMA comparative plastics in comparison to glass slides by 33.6 % and 24.8 % (P < 0.01), respectively. Both Candida strains had the highest level of fungal viability in biofilms on Breflex, Polyan and Protacryl basic materials (P < 0.01), and C. tropicalis biofilms on Biocryl and Vinacryl basic materials (P < 0.05). Integral coefficients indicated the inhibition of the oral microflora ability to form biofilms on the surfaces of basic materials. Conclusions. Oral α-hemolytic and β-hemolytic streptococci have the ability to intensive biofilm growth on the surfaces of the basic materials Protacryl and Vinacryl. Oral Candida albicans form massive biofilms on the surfaces of Biocryl and Vinacryl basic materials and comparative SYNMA plastics. The basic materials Breflex, Nylon and comparative plastics SYNMA are the most inert to biofilm formation by the oral microflora representatives.

scholarly journals Helicobacter pylori biofilm cells are metabolically distinct, express flagella, and antibiotic tolerant

2019 ◽  
Author(s):  
Skander Hathroubi ◽  
Julia Zerebinski ◽  
Karen M. Ottemann
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Susceptibility Gene ◽  
Tca Cycle ◽  
Surface Proteins ◽  
Biofilm Growth ◽  
Type Iv ◽  
Genes Encoding ◽  
Challenging Environment ◽  
H Pylori

ABSTRACTBiofilm growth protects bacteria against harsh environments, antimicrobials, and immune responses. Helicobacter pylori is a bacterium that has a robust ability to maintain colonization in a challenging environment. Over the last decade, H. pylori biofilm formation has begun to be characterized, however, there are still gaps in our understanding about how this growth mode is defined and its impact on H. pylori physiology. To provide insights into H. pylori biofilm growth properties, we characterized the antibiotic susceptibility, gene expression, and genes required for biofilm formation of a strong biofilm-producing H. pylori. H. pylori biofilms developed complex 3D structures and were recalcitrant to multiple antibiotics. Disruption of the protein-based matrix decreased this antibiotic tolerance. Using both transcriptomic and genomic approaches, we discovered that biofilm cells demonstrated lower transcripts for TCA cycle enzymes but higher ones for hydrogenase and acetone metabolism. Interestingly, several genes encoding for the natural competence Type IV secretion system 4 (tfs4) were up-regulated during biofilm formation along with several genes encoding for restriction-modification (R-M) systems, suggesting DNA exchange activities in this mode of growth. Flagella genes were also discovered through both approaches, consistent with previous reports about the importance of these filaments in H. pylori biofilm. Together, these data suggest that H. pylori is capable of adjusting its phenotype when grown as biofilm, changing its metabolism and elevating specific surface proteins including those encoding tfs4 and flagella.

Beneficial biofilms: A mini-review of strategies to enhance biofilm formation for biotechnological applications

2021 ◽  
Author(s):  
Mayur Mukhi ◽  
A. S. Vishwanathan
Keyword(s):  
Biofilm Formation ◽  
Environmental Remediation ◽  
Extracellular Polymeric Substances ◽  
External Environment ◽  
Bacterial Cells ◽  
Biotechnological Applications ◽  
Biofilm Growth ◽  
Research Attention ◽  
Signaling Systems ◽  
Biofilm Development

The capacity of bacteria to form biofilms is an important trait for their survival and persistence. Biofilms occur naturally in soil and aquatic environments, are associated with animals ranging from insects to humans and are also found in built environments. They are typically encountered as a challenge in healthcare, food industry, and water supply ecosystems. In contrast, they are known to play a key role in the industrial production of commercially valuable products, environmental remediation processes, and in microbe-catalysed electrochemical systems for energy and resource recovery from wastewater. While there are many recent articles on biofilm control and removal, review articles on promoting biofilm growth for biotechnological applications are unavailable. Biofilm formation is a tightly regulated response to perturbations in the external environment. The multi-stage process, mediated by an assortment of proteins and signaling systems, involves the attachment of bacterial cells to a surface followed by their aggregation in a matrix of extracellular polymeric substances. Biofilms can be promoted by altering the external environment in a controlled manner, supplying molecules that trigger the aggregation of cells and engineering genes associated with biofilm development. This mini-review synthesizes findings from studies that have described such strategies and highlights areas needing research attention.

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