Recent Trends in Biofilm Science and Technology

Manuel Simoes, Anabel Borges, Lucia Chaves Simoes

• Publisher: Academic Press
• Year: 2020
• Print ISBN: 9780128194973
• eBook ISBN: 9780128194980
• Topic: Biological Sciences
• Subtopic: Microbiology
• Index: Biological Sciences

Recent Trends in Biofilm Science and Technology helps researchers working on fundamental aspects of biofilm formation and control conduct biofilm studies and interpret results. The book provides a remarkable amount of knowledge on the processes that regulate biofilm formation, the methods used, monitoring characterization and mathematical modeling, the problems/advantages caused by their presence in the food industry, environment and medical fields, and the current and emergent strategies for their control. Research on biofilms has progressed rapidly in the last decade due to the fact that biofilms have required the development of new analytical tools and new collaborations between biologists, engineers and mathematicians.- Presents an overview of the process of biofilm formation and its implications- Provides a clearer understanding of the role of biofilms in infections- Creates a foundation for further research on novel control strategies- Updates readers on the remarkable amount of knowledge on the processes that regulate biofilm formation

Chapter 1

Biofilm formation and resistance

Astrid Gędas, and Magdalena A. Olszewska Department of Industrial and Food Microbiology, Faculty of Food Science, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland

Abstract

To increase the chance of survival, microorganisms form biofilms enclosed in self-produced extracellular polymeric substances (EPS). Biofilm formation is a complex process that depends on many factors, such as environmental conditions, specific strain attributes, and material surface properties. Biofilms are also responsible for the increased microbial resistance to antimicrobial agents, especially to antibiotics. This effect is reinforced by, e.g., persisters that—as a subpopulation of cells with slowed down metabolism—escape antibiotic treatment. This and many other biofilm-related resistance mechanisms are therefore important to be continuously studied to overcome serious problems biofilms caused in particular in the medicine field. In this chapter, we focus on the factors including molecular aspects that play a key role in both the biofilm formation process and the biofilm-based resistance to antimicrobials that bring new knowledge and insight in this regard.

Keywords

Biofilm formation process; Biofilm-based antibiotic resistance; Biofilms

1.1. Biofilm mode of growth

Overall, microorganisms exist in two modes of growth: a unicellular, in which single, free-living cells (planktonic) prevail in the microbial population, and a multicellular one, in which the cells bind to each other (cohesion) and to the substratum (adhesion) (Bjarnsholt, 2013). In nature, microbes barely occur as planktonic cells but instead exist as communities of sessile cells that grow as biofilms (Berlanga and Guerrero, 2016; Rabin et al., 2015; Donlan, 2002). Biofilms can be defined as aggregated microbial communities surrounded by a matrix of self-produced extracellular polymeric substances (EPS), which develop on a wide variety of inert or organic surfaces (Armbruster and Parsek, 2018; Kim and Lee, 2016).

Biofilm development depends upon different factors, including those associated with environmental conditions, specific strain attributes, and material surface properties (Chmielewski and Frank, 2003). In fact, biofilm formation is usually enhanced in harsh environmental conditions, such as nutrient-deficient or toxic media (Rendueles and Ghigo, 2015). Besides, microbes within the biofilm can coordinate their behavior for promoting growth and producing EPS (Moradali et al., 2017). The ability to form biofilms seems to be universal among microorganisms. Microbial communities exhibiting this ability may be composed not only of single species but of multiple species as well (O'Toole et al., 2000; López et al., 2010). In most biofilms, however, microorganisms account for less than 10% of the biofilm dry mass, whereas the EPS may account for over 90% (Flemming and Wingender, 2010; Tsagkari and Sloan, 2018). Indeed, this self-produced matrix is responsible for the cohesion and adhesion of cells, but more importantly, for the development of a microenvironment that allows the microbes for cell–cell interaction and communication and serves as a reservoir of metabolic substances, nutrients, and energy for biofilm inhabitants (Flemming and Wingender, 2010).

This highly hydrated EPS matrix is mainly composed of polysaccharides (PSs), but it can also consist of proteins, lipids, extracellular DNA (eDNA), and other biopolymers (Das et al., 2016; Kim and Lee, 2016; Kostakioti et al., 2013 ). The PSs synthesized by microbial cells differ significantly in their composition and thus in their chemical and physical properties (Limoli et al., 2015). For instance, in gram-negative bacteria, some PSs are neutral or polyanionic and hence rendered more anionic, whereas in gram-negative bacteria, the EPS show mostly cationic nature due to teichoic acid and certain quantities of proteins (Donlan, 2002; Vu et al., 2009). Enzymes may also play an important role in a biofilm life cycle, i.e., they can break down EPS polymers and provide carbon and energy during starvation or cause biofilm degradation during detachment and dispersal (Rabin et al., 2015). Several studies have shown the significance of enzymes particularly in releasing cells from biofilms to start a new biofilm life cycle (Petrova and Sauer, 2016). In biofilms, e.g., these formed by Vibrio cholerae and Pseudomonas aeruginosa, nonenzymatic proteins, such as lectins, which take part in formation and stabilization of the matrix, can also be found (Fong and Yildiz, 2015). Moreover, a crucial role in biofilm formation has recently been demonstrated for eDNAs which, among others, take part in cell adhesion. In the case of Staphylococcus aureus, eDNA is responsible for matrix structure and enables cell–cell as well as cell–surface interactions (Boles and Horswill, 2011). eDNA is also essential in cell-to-cell connection and in Pseudomonas biofilm stabilization especially at the initial stages of biofilm development, when the amount of EPS components is small (Kostakioti et al., 2013).

Not only composition but also the quantity of EPS changes depending on the type of microorganisms, the age of the biofilm, and current environmental conditions (Donlan, 2002). Importantly, EPS form the structure and architecture of the b...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Preface
• Acknowledgments
• Chapter 1. Biofilm formation and resistance
• Chapter 2. Nuclear magnetic resonance to study bacterial biofilms structure, formation, and resilience
• Chapter 3. Design and fabrication of biofilm reactors
• Chapter 4. Oral biofilms
• Chapter 5. The role of filamentous fungi in drinking water biofilm formation
• Chapter 6. Microalgal and cyanobacterial biofilms
• Chapter 7. Biofilms in membrane systems for drinking water production
• Chapter 8. Biofilm fuel cells
• Chapter 9. Application of lactic acid bacteria and their metabolites against foodborne pathogenic bacterial biofilms
• Chapter 10. Role of equipment design in biofilm prevention
• Chapter 11. Biofilm control with enzymes
• Chapter 12. The potential of phytochemical products in biofilm control
• Chapter 13. Photoinactivation of biofilms
• Chapter 14. The potential of drug repurposing to face bacterial and fungal biofilm infections
• Chapter 15. In silico development of quorum sensing inhibitors
• Chapter 16. Challenges and perspectives in reactor scale modeling of biofilm processes
• Index