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

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

10.26434/chemrxiv.10001924.v1 ◽

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

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. Acinetobacter 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.

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Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666191112155905 ◽

2020 ◽

Vol 21 (4) ◽

pp. 270-286 ◽

Cited By ~ 2

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.

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Evidence of cannibalism during long-term biofilm-antimicrobials interaction

10.5194/biofilms9-144 ◽

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

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. 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. <div> [1] N. Billings et al., Rep. Prog. Phys., 2015, 78, 036601. [2] D.O. Serra et al., MBio., 2013, 4, e00103. [3] C. H&#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. </div>

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Effects ofBacillusSerine Proteases on the Bacterial Biofilms

BioMed Research International ◽

10.1155/2017/8525912 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 12

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.

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Bacteriophages as an Alternative Strategy for Fighting Biofilm Development

Polish Journal of Microbiology ◽

10.33073/pjm-2014-019 ◽

2014 ◽

Vol 63 (2) ◽

pp. 137-145 ◽

Cited By ~ 56

Author(s):

SYLWIA PARASION ◽

MAGDALENA KWIATEK ◽

ROMUALD GRYKO ◽

LIDIA MIZAK ◽

ANNA MALM

Keyword(s):

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Bacterial Resistance ◽

Bacterial Species ◽

Experimental Studies ◽

Alternative Methods ◽

Resistant Bacteria ◽

Bacterial Cells ◽

Coagulase Negative Staphylococci ◽

Biofilm Development

The ability of microbes to form biofilms is an important element of their pathogenicity, and biofilm formation is a serious challenge for today's medicine. Fighting the clinical complications associated with biofilm formation is very difficult and linked to a high risk of failure, especially in a time of increasing bacterial resistance to antibiotics. Bacterial species most commonly isolated from biofilms include coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. The frequent failure of antibiotic therapy led researchers to look for alternative methods and experiment with the use of antibacterial factors with a mechanism of action different from that of antibiotics. Experimental studies with bacteriophages and mixtures thereof, expressing lytic properties against numerous biofilm-forming bacterial species showed that bacteriophages may both prevent biofilm formation and contribute to eradication of biofilm bacteria. A specific role is played here by phage depolymerases, which facilitate the degradation of extracellular polymeric substances (EPS) and thus the permeation of bacteriophages into deeper biofilm layers and lysis of the susceptible bacterial cells. Much hope is placed in genetic modifications of bacteriophages that would allow the equipping bacteriophages with the function of depolymerase synthesis. The use of phage cocktails prevents the development of phage-resistant bacteria.

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

10.26434/chemrxiv.10001924 ◽

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

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

Applied and Environmental Microbiology ◽

10.1128/aem.01994-21 ◽

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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Improved micro-impedance spectroscopy to determine cell barrier properties

The EuroBiotech Journal ◽

10.2478/ebtj-2020-0017 ◽

2020 ◽

Vol 4 (3) ◽

pp. 150-155 ◽

Cited By ~ 1

Author(s):

Md. Mehadi Hasan Sohag ◽

Olivier Nicoud ◽

Racha Amine ◽

Abir Khalil-Mgharbel ◽

Jean-Pierre Alcaraz ◽

...

Keyword(s):

Impedance Spectroscopy ◽

Epithelial Cells ◽

Lipid Bilayers ◽

Cultured Cells ◽

Cell Model ◽

Measurement Techniques ◽

Cell Monolayer ◽

Microfluidic Channel ◽

Small Surface ◽

Resistance Pathway

AbstractThe goal of this study was to determine whether the Tethapod system, which was designed to determine the impedance properties of lipid bilayers, could be used for cell culture in order to utilise micro-impedance spectroscopy to examine further biological applications. To that purpose we have used normal epithelial cells from kidney (RPTEC) and a kidney cancer cell model (786-O). We demonstrate that the Tethapod system is compatible with the culture of 10,000 cells seeded to grow on a small area gold measurement electrode for several days without affecting the cell viability. Furthermore, the range of frequencies for EIS measurements were tuned to examine easily the characteristics of the cell monolayer. We demonstrate significant differences in the paracellular resistance pathway between normal and cancer kidney epithelial cells. Thus, we conclude that this device has advantages for the study of cultured cells that include (i) the configuration of measurement and reference electrodes across a microfluidic channel, and (ii) the small surface area of 6 parallel measurement electrodes (2.1 mm2) integrated in a microfluidic system. These characteristics might improve micro-impedance spectroscopy measurement techniques to provide a simple tool for further studies in the field of the patho-physiology of biological barriers.

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Modulation of Gut Microbiota through Dietary Phytochemicals as a Novel Anti-infective Strategy

Current Drug Discovery Technologies ◽

10.2174/1570163816666191107124214 ◽

2020 ◽

Vol 17 (4) ◽

pp. 498-506 ◽

Cited By ~ 2

Author(s):

Pavan K. Mujawdiya ◽

Suman Kapur

Keyword(s):

Microbial Community ◽

Quorum Sensing ◽

Population Density ◽

Gut Microbiota ◽

Biofilm Formation ◽

Chemical Interaction ◽

Bacterial Species ◽

Critical Role ◽

Bacterial Cells ◽

Gut Microbes

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.

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Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽

10.3390/agronomy11030546 ◽

2021 ◽

Vol 11 (3) ◽

pp. 546

Author(s):

Pilar Sabuquillo ◽

Jaime Cubero

Keyword(s):

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Environmental Changes ◽

Nutrient Content ◽

Infection Process ◽

Bacterial Attachment ◽

Key Factors ◽

Cell Structures ◽

Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

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