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.

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.

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

scholarly journals Comparative biofilm assays using Enterococcus faecalis OG1RF identify new determinants of biofilm formation

2021 ◽  
Author(s):  
Julia L. E. Willett ◽  
Jennifer L. Dale ◽  
Lucy M. Kwiatkowski ◽  
Jennifer L. Powers ◽  
Michelle L. Korir ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Growth Medium ◽  
Biofilm Formation ◽  
Time Course ◽  
Opportunistic Pathogen ◽  
Genetic Determinants ◽  
Experimental Conditions ◽  
Biofilm Reactors ◽  
Biofilm Architecture ◽  
Biofilm Development

AbstractEnterococcus faecalis is a common commensal organism and a prolific nosocomial pathogen that causes biofilm-associated infections. Numerous E. faecalis OG1RF genes required for biofilm formation have been identified, but few studies have compared genetic determinants of biofilm formation and biofilm morphology across multiple conditions. Here, we cultured transposon (Tn) libraries in CDC biofilm reactors in two different media and used Tn sequencing (TnSeq) to identify core and accessory biofilm determinants, including many genes that are poorly characterized or annotated as hypothetical. Multiple secondary assays (96-well plates, submerged Aclar, and MultiRep biofilm reactors) were used to validate phenotypes of new biofilm determinants. We quantified biofilm cells and used fluorescence microscopy to visualize biofilms formed by 6 Tn mutants identified using TnSeq and found that disrupting these genes (OG1RF_10350, prsA, tig, OG1RF_10576, OG1RF_11288, and OG1RF_11456) leads to significant time- and medium-dependent changes in biofilm architecture. Structural predictions revealed potential roles in cell wall homeostasis for OG1RF_10350 and OG1RF_11288 and signaling for OG1RF_11456. Additionally, we identified growth medium-specific hallmarks of OG1RF biofilm morphology. This study demonstrates how E. faecalis biofilm architecture is modulated by growth medium and experimental conditions, and identifies multiple new genetic determinants of biofilm formation.ImportanceE. faecalis is an opportunistic pathogen and a leading cause of hospital-acquired infections, in part due to its ability to form biofilms. A complete understanding of the genes required for E. faecalis biofilm formation as well as specific features of biofilm morphology related to nutrient availability and growth conditions is crucial for understanding how E. faecalis biofilm-associated infections develop and resist treatment in patients. We employed a comprehensive approach to analysis of biofilm determinants by combining TnSeq primary screens with secondary phenotypic validation using diverse biofilm assays. This enabled identification of numerous core (important under many conditions) and accessory (important under specific conditions) biofilm determinants in E. faecalis OG1RF. We found multiple genes whose disruption results in drastic changes to OG1RF biofilm morphology. These results expand our understanding of the genetic requirements for biofilm formation in E. faecalis that affect the time course of biofilm development as well as the response to specific nutritional conditions.

Evidence of cannibalism during long-term biofilm-antimicrobials interaction

2020 ◽  
Author(s):  
Maria Chiara Sportelli ◽  
Giada Caniglia ◽  
Ruggiero Quarto ◽  
Rosaria Anna Picca ◽  
Antonio Valentini ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Antimicrobial Agents ◽  
Survival Strategies ◽  
Bacterial Cells ◽  
Ion Release ◽  
Swelling Properties ◽  
Morphological Studies ◽  
Molecular Information

&lt;p&gt;Biofilms are considered a major cause of serious health issues in human medicine and food industry, due to their resistance against harsh conditions and pharmacological treatment [1]. Biofilms are defined as three-dimensional structures encasing bacterial communities rooted in extracellular polymeric substances (EPS). These complex systems are strongly influenced by a variety of parameters including biofilm age, external conditions, nutrient deficiency, attack of exogenous agents [2]. Moreover, bacterial colonies may activate survival strategies when subjected to stress such as the presence of antimicrobial agents. Even cannibalistic behavior may occur [3], which involves the secretion of cannibalism toxins inducing the generation of lysed cells providing nutrients.&lt;/p&gt; &lt;p&gt;Several methodologies were developed for or adapted to biofilm formation studies enabling a more comprehensive understanding of biofilm physiology, structure, and composition. This information should facilitate the development of more effective eradication strategies. Infrared spectroscopy in attenuated total reflectance (IR-ATR) mode provides in-situ and close to real time monitoring of biofilm lifecycles providing molecular information on the various stages of biofilm formation. Given the antibiotic resistance of biofilms [4], it is of increasing importance to develop innovative methodologies for the treatment of biofilm-related infections. While our research team has shown the generic utility of antimicrobial nanoparticles (NPs) such as ZnONPs, AgNPs, CuNPs, etc. in the past [5], the current study focuses on AgNPs embedded within fluoropolymer matrices with tunable loading of the NPs. Next to morphological studies by TEM and AFM, detailed XPS investigations revealed the surface chemical composition. In addition, the kinetics of antimicrobial ion release enabled correlating the behavior of the nanocomposite to its swelling properties and 3D modification after immersion in liquids. Biofilm growth and inhibition was studied via AFM, optical microscopy and IR-ATR. The IR analysis of the biofilm allowed collecting molecular information on the biofilm behavior during long-term contact with antimicrobial surfaces. It was demonstrated that bacterial cells may re-colonize on top of dead biomass once the latter is thick enough to prevent direct interaction with the antimicrobial surface. In summary, this study represents an excellent foundation for developing an in depth understanding on the behavior of bacterial colonies and nascent biofilms in contact with surfaces decorated with nanoantimicrobials over extended periods of time. It is anticipated that an improved understanding on the stages of biofilm formation provides insight into the processes governing antimicrobial resistance phenomena. Finally, present antimicrobial material may be a useful strategy against Corona viruses. An outlook to this urging topic will be also presented.&lt;/p&gt; &lt;div&gt; &lt;p&gt;[1] N. Billings et al., Rep. Prog. Phys., 2015, 78, 036601. [2] D.O. Serra et al., MBio., 2013, 4, e00103. [3] C. H&amp;#246;fler et al., Microbiology, 2016, 162, 164. [4] M.C. Sportelli et al., Sci. Rep., 2017, 7, 11870. [5] M.C. Sportelli et al., TrAC, 2016, 84, 131.&lt;/p&gt; &lt;/div&gt;

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

&lt;p&gt;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.&amp;#160; 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.&lt;/p&gt; &lt;p&gt;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. &amp;#160;&lt;/p&gt; &lt;p&gt;In this study, we fabricated different &amp;#160;biomimetic surfaces (rose-petal surfaces and slippery liquid-infused porous surfaces). &amp;#160;&amp;#160;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&amp;#160; biofilm &amp;#160;formation according to surface structures.&amp;#160; The mechanisms of hierarchical structures &amp;#160;of rose-petal influence biofilm formation are two folds: 1) Papillae microstructure block &amp;#160;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.&lt;/p&gt; &lt;p&gt;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.&amp;#160; These are mainly attributed to their high contact angle and extreme low contact angle hysteresis.&lt;/p&gt;

scholarly journals Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism

2017 ◽  
Author(s):  
Damien Keogh ◽  
Ling Ning Lam ◽  
Lucinda E. Doyle ◽  
Artur Matysik ◽  
Shruti Pavagadhi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Enterococcus Faecalis ◽  
Bacterial Biofilm ◽  
Extracellular Electron Transfer ◽  
Bacterial Cells ◽  
Free Living ◽  
Biofilm Growth ◽  
Metabolic Versatility ◽  
Tract Infections ◽  
Biofilm Matrix

AbstractEnterococci are important human commensals and significant opportunistic pathogens associated with endocarditis, urinary tract infections, wound and surgical site infections, and medical device associated infections. These infections often become chronic upon the formation of biofilm. The biofilm matrix establishes properties that distinguish this state from free-living bacterial cells and increase tolerance to antimicrobial interventions. The metabolic versatility of the Enterococci is reflected in the diversity and complexity of environments and communities in which they thrive. Understanding metabolic factors governing colonization and persistence in different host niches can reveal factors influencing the transition from commensal to opportunistic pathogen. Here, we report a new form of iron-dependent metabolism for Enterococcus faecalis where, in the absence of heme, respiration components can be utilised for extracellular electron transfer (EET). Iron augments E. faecalis biofilm growth and generates alterations in biofilm matrix, cell spatial distribution, and biofilm matrix properties. We identify the genes involved in iron-augmented biofilm growth and show that it occurs by promoting EET to iron within biofilm.SignificanceBacterial metabolic versatility is often key in dictating the outcome of host-pathogen interactions, yet determinants of metabolic shifts are difficult to resolve. The bacterial biofilm matrix provides the structural and functional support that distinguishes this state from free-living bacterial cells. Here, we show that the biofilm matrix provides access to resources necessary for metabolism and growth which are otherwise inaccessible in the planktonic state. Our data shows that in the absence of heme, components of Enterococcus faecalis respiration (l-lactate dehydrogenase and acetaldehyde dehydrogenase) may function as initiators of EET through the cytoplasmic membrane quinone pool and utilize matrix-associated iron to carry out EET. The presence of iron resources within the biofilm matrix leads to enhanced biofilm growth.

scholarly journals A modified crystal violet assay is comparable to XTT reduction assay for quantification of biofilm formation by Candida albicans

2020 ◽  
Author(s):  
Yue Qu ◽  
Shoufeng Yang ◽  
Zhangzhang Chen ◽  
Feifei Su
Keyword(s):  
Candida Albicans ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Quantitative Methods ◽  
Standard Procedure ◽  
Short Term ◽  
Biofilm Growth ◽  
Human Fungal Pathogen ◽  
Crystal Violet Assay ◽  
Reduction Assay

Abstract Background: The ability of the human fungal pathogen Candida albicans to form biofilms, for example on indwelling medical devices, is a major pathogenic mechanism and has been the focus of intense studies in the fungal pathogenesis field. A key research tool used is the quantitative methods for measuring biofilm formation of C. albicans. Objective: We sought to optimize the conventional crystal violet (CV) staining assay for quantification of biofilm formation by C. albicans and evaluate its performance. Methods: Individual modifications included (i) submerge-washing of microplates to remove non-adherent cells, (ii) heat-fixation, (iii) short-term staining for 3 min, (iv) submerge-washing to remove unbound CV dye, and (v) short-term destaining for 15 min were compared with the standard procedure, and those were superior were incorporated. Performance analysis was carried out for the modified CV assay, in comparison to the conventional CV assay and the XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide] reduction assay. Results: The modified CV assay demonstrated several advantages in quantitative assessment of biofilm formation of C. albicans over the conventional CV assay, including greater accuracy and reproducibility, shorter experimental time and reduced labor intensity, and was at least comparable to the XTT reduction assay.Conclusion: The modified CV method can be used as an alternative to the XTT reduction assay in quantification of biofilm growth by C. albicans.

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.

scholarly journals Embedded Biofilm, a New Biofilm Model Based on the Embedded Growth of Bacteria

2014 ◽  
Vol 81 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Yong-Gyun Jung ◽  
Jungil Choi ◽  
Soo-Kyoung Kim ◽  
Joon-Hee Lee ◽  
Sunghoon Kwon
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Cell Model ◽  
Microfluidic Channel ◽  
Developmental Cycle ◽  
Bacterial Cells ◽  
Clinical Environment ◽  
Biofilm Model ◽  
Cell Model System ◽  
Embedded Type

ABSTRACTA variety of systems have been developed to study biofilm formation. However, most systems are based on the surface-attached growth of microbes under shear stress. In this study, we designed a microfluidic channel device, called a microfluidic agarose channel (MAC), and found that microbial cells in the MAC system formed an embedded cell aggregative structure (ECAS). ECASs were generated from the embedded growth of bacterial cells in an agarose matrix and better mimicked the clinical environment of biofilms formed within mucus or host tissue under shear-free conditions. ECASs were developed with the production of extracellular polymeric substances (EPS), the most important feature of biofilms, and eventually burst to release planktonic cells, which resembles the full developmental cycle of biofilms. Chemical and genetic effects have also confirmed that ECASs are a type of biofilm. Unlike the conventional biofilms formed in the flow cell model system, this embedded-type biofilm completes the developmental cycle in only 9 to 12 h and can easily be observed with ordinary microscopes. We suggest that ECASs are a type of biofilm and that the MAC is a system for observing biofilm formation.

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