Evidence of cannibalism during long-term biofilm-antimicrobials interaction

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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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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Application of Bacteriophages on Shiga Toxin-Producing Escherichia coli (STEC) Biofilm

Antibiotics ◽

10.3390/antibiotics10111423 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1423

Author(s):

Nicola Mangieri ◽

Roberto Foschino ◽

Claudia Picozzi

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Biofilm Formation ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Bacterial Cells ◽

Abiotic Surfaces ◽

Continuous Presence ◽

Different Strains ◽

Better Than

Shiga toxin-producing Escherichia coli are pathogenic bacteria able to form biofilms both on abiotic surfaces and on food, thus increasing risks for food consumers. Moreover, biofilms are difficult to remove and more resistant to antimicrobial agents compared to planktonic cells. Bacteriophages, natural predators of bacteria, can be used as an alternative to prevent biofilm formation or to remove pre-formed biofilm. In this work, four STEC able to produce biofilm were selected among 31 different strains and tested against single bacteriophages and two-phage cocktails. Results showed that our phages were able to reduce biofilm formation by 43.46% both when used as single phage preparation and as a cocktail formulation. Since one of the two cocktails had a slightly better performance, it was used to remove pre-existing biofilms. In this case, the phages were unable to destroy the biofilms and reduce the number of bacterial cells. Our data confirm that preventing biofilm formation in a food plant is better than trying to remove a preformed biofilm and the continuous presence of bacteriophages in the process environment could reduce the number of bacteria able to form biofilms and therefore improve the food safety.

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

Applied and Environmental Microbiology ◽

10.1128/aem.02311-14 ◽

2014 ◽

Vol 81 (1) ◽

pp. 211-219 ◽

Cited By ~ 15

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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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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Efficacy of Usnea sp. Extracts in Preventing Biofilm Formation by Bacillus Species Isolated from Soaking Liquor Samples

Journal of the American Leather Chemists Association ◽

10.34314/jalca.v115i6.3820 ◽

2020 ◽

Vol 115 (6) ◽

pp. 222-229

Author(s):

Didem Berber ◽

İpek Türkmenoğlu ◽

Meral Birbir ◽

Nüzhet Cenk Sesal

Keyword(s):

Biofilm Formation ◽

Antibacterial Agents ◽

Bacterial Resistance ◽

Antimicrobial Agents ◽

Biological Activities ◽

Bacillus Species ◽

Bacterial Biofilms ◽

Bacterial Cells ◽

Leather Industry ◽

Acetone Extracts

Bacteria forms biofilm to be resistant to antibacterial agents and other unfavorable environment as compared to planktonic bacterial cells. Due to resistance of bacterial biofilms to commonly used antimicrobial agents and adverse effects of these biofilms in different industries, potential natural compounds which can inhibit bacterial biofilms have attracted more attention in recent years. Lichens are known to have unique secondary metabolites with various biological activities including anti-biofilm properties. Therefore, Bacillus toyonensis, Bacillus mojavensis, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus cereus, and Bacillus licheniformis, isolated from soak liquor samples in the previous study, were tested for their ability to form biofilm in this study. Biofilm-forming Bacillus species were detected as B. subtilis, B. amyloliquefaciens, and B. velezensis. The anti-biofilm effect of the acetone extracts of Usnea sp. was evaluated at various concentrations against these biofilm-forming isolates. The anti-biofilm effect of acetone extracts of Usnea sp. against B. subtilis and B. amyloliquefaciens was observed at the concentration of 5 µg/mL by inhibition ratios of 62.75% and 72.72%, respectively. In addition, biofilm formation of B. velezensis was inhibited by the treatment with 1.25 µg/mL extracts at a 62.69% inhibition rate. Biofilm formations of B. amyloliquefaciens and B. velezensis were also suppressed by the extracts at varying percentages of inhibition ranging between 10.11-43.69% and 21.25-46.35%, respectively. This study may provide an alternative approach to overcome the biofilm formation and bacterial resistance to the antibacterial agents in the leather industry.

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Antibacterial Effect of Lime (Citrus aurantifolia) Peel Extract in Preventing Biofilm Formation

Journal Of Medicine & Health ◽

10.28932/jmh.v2i4.1841 ◽

2019 ◽

Vol 2 (4) ◽

Author(s):

Jeffrey Jeffrey ◽

Mieke H Satari ◽

Dikdik Kurnia

Keyword(s):

Streptococcus Mutans ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Therapeutic Potential ◽

Dental Health ◽

Bacterial Cells ◽

Citrus Aurantifolia ◽

Adverse Environmental Conditions ◽

Lime Peel ◽

Peel Extract

The routine and long term use of chemicals to maintain oral and dental health have the potency to result in the emergence of side effects; therefore another strategy is needed as an alternative such as using antimicrobial agents extracted from plants. The purpose of this study is to review the effectiveness of lime (Citrus aurantifolia) peel extract as an antibacterial in preventing biofilm formation. Biofilm is a component consisting of bacteria in a self-produced polymeric matrix, attached to an inert surface, alive, and can survive because of its ability to capture nutrients and withstand adverse environmental conditions. Lime peel contains flavonoids which are the largest group of polyphenol compounds that can work as antioxidants and antibacterial by denaturing bacterial cell proteins and damaging bacterial cells. Flavonoids can also inhibit glucosyltransferase (GTF) activity of Streptococcus mutans to prevent biofilm formation. Lime peel extract inhibits the formation of the activity of the enzyme Streptococcus mutans. As a conclusion lime peel extract contains compounds with therapeutic potential and has the effect of inhibiting the formation of the activity of the enzyme Streptococcus mutans so that it can be used to inhibit the formation of biofilms. Keywords: antibacterial, biofilm, Citrus aurantifolia

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

Membranes ◽

10.3390/membranes10090227 ◽

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.

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