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Microbiological Research Nov 2022Pseudomonas aeruginosa, a ubiquitous opportunistic and nosocomial biofilm-forming pathogen with complex, interconnected and hierarchical nature of QS systems (Las, Rhl,... (Review)
Review
Pseudomonas aeruginosa, a ubiquitous opportunistic and nosocomial biofilm-forming pathogen with complex, interconnected and hierarchical nature of QS systems (Las, Rhl, PQS, and IQS), is posing the biggest challenge to the healthcare sector and have made current chemotherapies incapable. Conventional antibiotics designed to intercept the biochemical or physiological processes precisely of planktonic microorganisms exert extreme selective pressure and develop resistance against them thereby emphasizing the development of alternative therapeutic approaches. Additionally, quorum sensing induced pathogenic microbial biofilms and production of virulence factors have intensified the pathogenicity, drug resistance, recurrence of infections, hospital visits, morbidity, and mortality many-folds. In this regard, QS could be a potential druggable target and the discovery of QS inhibiting agents as an anti-virulent measure could serve as an alternative therapeutic approach to conventional antibiotics. Quorum quenching (QQ) is a preferred strategy to combat microbial infections since it attenuates the pathogenicity of microbes and enhances the microbial biofilm susceptibility to antibiotics, thus qualifying as a suitable target for drug discovery. This review discusses the QS-induced pathogenicity of P. aeruginosa, the hierarchical QS systems, and QS inhibition as a drug discovery approach to complement classical antibiotic strategy.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Drug Discovery; Humans; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing; Virulence Factors
PubMed: 36037563
DOI: 10.1016/j.micres.2022.127173 -
Nature Communications Jul 2022Employing renewable materials for fabricating clean energy harvesting devices can further improve sustainability. Microorganisms can be mass produced with renewable...
Employing renewable materials for fabricating clean energy harvesting devices can further improve sustainability. Microorganisms can be mass produced with renewable feedstocks. Here, we demonstrate that it is possible to engineer microbial biofilms as a cohesive, flexible material for long-term continuous electricity production from evaporating water. Single biofilm sheet (~40 µm thick) serving as the functional component in an electronic device continuously produces power density (~1 μW/cm) higher than that achieved with thicker engineered materials. The energy output is comparable to that achieved with similar sized biofilms catalyzing current production in microbial fuel cells, without the need for an organic feedstock or maintaining cell viability. The biofilm can be sandwiched between a pair of mesh electrodes for scalable device integration and current production. The devices maintain the energy production in ionic solutions and can be used as skin-patch devices to harvest electricity from sweat and moisture on skin to continuously power wearable devices. Biofilms made from different microbial species show generic current production from water evaporation. These results suggest that we can harness the ubiquity of biofilms in nature as additional sources of biomaterial for evaporation-based electricity generation in diverse aqueous environments.
Topics: Bioelectric Energy Sources; Biofilms; Electricity; Electrodes; Water; Wearable Electronic Devices
PubMed: 35902587
DOI: 10.1038/s41467-022-32105-6 -
International Journal of Environmental... Feb 2021Biofilms, present as microorganisms and surviving on surfaces, can increase food cross-contamination, leading to changes in the food industry's cleaning and disinfection... (Review)
Review
Biofilms, present as microorganisms and surviving on surfaces, can increase food cross-contamination, leading to changes in the food industry's cleaning and disinfection dynamics. Biofilm is an association of microorganisms that is irreversibly linked with a surface, contained in an extracellular polymeric substance matrix, which poses a formidable challenge for food industries. To avoid biofilms from forming, and to eliminate them from reversible attachment and irreversible stages, where attached microorganisms improve surface adhesion, a strong disinfectant is required to eliminate bacterial attachments. This review paper tackles biofilm problems from all perspectives, including biofilm-forming pathogens in the food industry, disinfectant resistance of biofilm, and identification methods. As biofilms are largely responsible for food spoilage and outbreaks, they are also considered responsible for damage to food processing equipment. Hence the need to gain good knowledge about all of the factors favouring their development or growth, such as the attachment surface, food matrix components, environmental conditions, the bacterial cells involved, and electrostatic charging of surfaces. Overall, this review study shows the real threat of biofilms in the food industry due to the resistance of disinfectants and the mechanisms developed for their survival, including the intercellular signalling system, the cyclic nucleotide second messenger, and biofilm-associated proteins.
Topics: Biofilms; Disinfectants; Extracellular Polymeric Substance Matrix; Food Handling; Food Industry; Food Microbiology; Food-Processing Industry
PubMed: 33669645
DOI: 10.3390/ijerph18042014 -
Journal of Applied Microbiology Aug 2020Soil environments are dynamic and the plant rhizosphere harbours a phenomenal diversity of micro-organisms which exchange signals and beneficial nutrients. Bipartite... (Review)
Review
Soil environments are dynamic and the plant rhizosphere harbours a phenomenal diversity of micro-organisms which exchange signals and beneficial nutrients. Bipartite beneficial or symbiotic interactions with host roots, such as mycorrhizae and various bacteria, are relatively well characterized. In addition, a tripartite interaction also exists between plant roots, arbuscular mycorrhizal fungi (AMF) and associated bacteria. Bacterial biofilms exist as a sheet of bacterial cells in association with AMF structures, embedded within a self-produced exopolysaccharide matrix. Such biofilms may play important functional roles within these tripartite interactions. However, the details about such interactions in the rhizosphere and their relevant functional relationships have not been elucidated. This review explores the current understanding of naturally occurring microbial biofilms, and their interaction with biotic surfaces, especially AMF. The possible roles played by bacterial biofilms and the potential for their application for a more productive and sustainable agriculture is discussed in this review.
Topics: Agriculture; Bacterial Physiological Phenomena; Biofilms; Mycorrhizae; Plant Roots; Rhizosphere; Soil Microbiology; Symbiosis
PubMed: 32034822
DOI: 10.1111/jam.14609 -
Critical Reviews in Microbiology Feb 2021Biofilms are complex microbial architectures that encase microbial cells in a matrix comprising self-produced extracellular polymeric substances. Microorganisms living... (Review)
Review
Biofilms are complex microbial architectures that encase microbial cells in a matrix comprising self-produced extracellular polymeric substances. Microorganisms living in biofilms are much more resistant to hostile environments than their planktonic counterparts and exhibit enhanced resistance against the microbicides. From the human perspective, biofilms can be classified into beneficial, neutral, and harmful. Harmful biofilms impact food safety, cause plant and animal diseases, and threaten medical fields, making it urgent to develop effective and robust strategies to control harmful biofilms. In this review, we discuss various strategies to control biofilm formation on infected tissues, implants, and medical devices. We classify the current strategies into three main categories: (i) changing the properties of susceptible surfaces to prevent biofilm formation; (ii) regulating signalling pathways to inhibit biofilm formation; (iii) applying external forces to eradicate the biofilm. We hope this review would motivate the development of innovative and effective strategies for controlling harmful biofilms.
Topics: Animals; Anti-Infective Agents; Bacteria; Bacterial Infections; Bacterial Physiological Phenomena; Biofilms; Humans; Prostheses and Implants
PubMed: 33356690
DOI: 10.1080/1040841X.2020.1842325 -
Water Research Sep 2021Granular biofilms are dense spherical complex biological systems composed mainly of multi-microbial cells, water, and extracellular polymeric substances (EPS). They...
Granular biofilms are dense spherical complex biological systems composed mainly of multi-microbial cells, water, and extracellular polymeric substances (EPS). They facilitate efficient purification and settling of activated sludge in wastewater treatment processes. The viscoelastic properties of these complex biofilm systems are important characteristics that control their growth and dictate how they respond to hydrodynamic forces and chemical stimuli. However, the viscoelastic properties of granular biofilms are poorly understood. In this paper, we study granular biofilms' viscoelastic properties using optical coherence elastography (OCE), a nondestructive method that integrates optical coherence tomography (OCT) with elastic wave propagation. While quantitative viscoelastic characterization of granular biofilms is challenging due to their heterogeneous properties, we show that elastic waves are suitable for this purpose. First, we employ guided elastic waves in a thin section of a granular biofilm to reveal a two-layered profile for the viscoelastic properties. Next, we utilize circumferential elastic waves that propagate near the surface of a non-sectioned spherical biofilm to quantify the layered system's viscoelastic properties. To the best of our knowledge, this work is the first quantitative study that characterizes the layered viscoelastic properties of granular biofilms. The measurement approach may provide a platform to study the interplay between the viscoelastic properties and other characteristics of granular biofilms such as the complex microbial system, morphology, and oxygen distribution.
Topics: Biofilms; Sewage; Water Purification
PubMed: 34256191
DOI: 10.1016/j.watres.2021.117394 -
NPJ Biofilms and Microbiomes Nov 2021Biofilms are organised heterogeneous assemblages of microbial cells that are encased within a self-produced matrix. Current estimates suggest that up to 80% of bacterial... (Review)
Review
Biofilms are organised heterogeneous assemblages of microbial cells that are encased within a self-produced matrix. Current estimates suggest that up to 80% of bacterial and archaeal cells reside in biofilms. Since biofilms are the main mode of microbial life, understanding their biology and functions is critical, especially as controlling biofilm growth is essential in industrial, infrastructure and medical contexts. Here we discuss biofilms both as collections of individual cells, and as multicellular biological individuals, and introduce the concept of biofilms as unique incubators of diversity for the microbial world.
Topics: Archaea; Bacteria; Biofilms; Humans; Life Style
PubMed: 34759294
DOI: 10.1038/s41522-021-00251-2 -
Journal of Basic Microbiology Mar 2020The growth of technology and requirements globally for various commodities has brought about new challenges. Biofilms are aggregations of microbial cells, which... (Review)
Review
The growth of technology and requirements globally for various commodities has brought about new challenges. Biofilms are aggregations of microbial cells, which contaminate and spoil industrial components and environments. These microbial cells with extracellular polymeric substances colonize living and nonliving surfaces and pose a serious problem for all industries, affecting their processes, leading to a reduction of product quality and economic loss. Industries, such as medical, food, water, dairy, wine, marine, power plants are exposed to biofilm formation. Pipe blockages, waterlogging and reduction of the heat-transfer efficiency, hamper the operating system of plants. Many industries do not set up remedial measures to control biofilm formation as they are not aware of this threat. Various conventional methods to control these biofilms are adopted by industries in their regular workflow, but these are temporary solutions. This calls for further research into remediation of the biofilm and its control for industrial components. This review article addresses the problems of biofilms and proposes solutions for various industrial components. Nanotechnology promises several options, and bring about a new aspect into the industrial economy, by solving the problems of environmental biofilms.
Topics: Biofilms; Biofouling; Environmental Microbiology; Industry; Nanotechnology
PubMed: 31856349
DOI: 10.1002/jobm.201900569 -
International Journal of Molecular... Nov 2021Microbial biofilms occur naturally in many environmental niches and can be a significant reservoir of infectious microbes in zoonotically transmitted diseases such as... (Review)
Review
Microbial biofilms occur naturally in many environmental niches and can be a significant reservoir of infectious microbes in zoonotically transmitted diseases such as that caused by , the leading cause of acute human bacterial gastroenteritis world-wide. The greatest challenge in reducing the disease caused by this organism is reducing transmission of to humans from poultry via the food chain. Biofilms enhance the stress tolerance and antimicrobial resistance of the microorganisms they harbor and are considered to play a crucial role for spp. survival and transmission to humans. Unconventional approaches to control biofilms and to improve the efficacy of currently used antibiotics are urgently needed. This review summarizes the use plant- and microorganism-derived antimicrobial and antibiofilm compounds such as essential oils, antimicrobial peptides (AMPs), polyphenolic extracts, algae extracts, probiotic-derived factors, d-amino acids (DAs) and glycolipid biosurfactants with potential to control biofilms formed by , and the suggested mechanisms of their action. Further investigation and use of such natural compounds could improve preventative and remedial strategies aimed to limit the transmission of campylobacters and other human pathogens via the food chain.
Topics: Animals; Antimicrobial Peptides; Biofilms; Campylobacter Infections; Campylobacter jejuni; Humans; Oils, Volatile; Poultry
PubMed: 34830039
DOI: 10.3390/ijms222212159 -
The Cleft Palate-craniofacial Journal :... Apr 2020Maxillofacial prosthetics includes restoration of maxillary defects resulting from resection of palate and nasosinus neoplasms with obturator prostheses which may be... (Review)
Review
BACKGROUND
Maxillofacial prosthetics includes restoration of maxillary defects resulting from resection of palate and nasosinus neoplasms with obturator prostheses which may be colonized by microorganisms and function as a reservoir of infection. Patients with neoplasms commonly also require radiotherapy that can result in changes in saliva quality and quantity and changes in the oral microbial flora. The altered flora, in individuals immunocompromised from cancer therapy, increases their risk of prosthesis-related infections.
OBJECTIVES
In this review article, we explore microbial biofilms, their main components, mechanisms of microbial adhesion, and stages of biofilm development. We also discuss the different materials that are used for manufacturing maxillary obturators, their characteristic features, and how these can affect microbial adhesion. Furthermore, we shed some light on the factors that affect microbial adhesion to the surface of maxillary obturators including tissue proteins, protein adsorption, and the acquired enamel pellicle.
CONCLUSIONS
The conclusions drawn from this literature review are that it is imperative to minimize the risk of local and systemic infections in immunocompromised patients with cancer having maxillary defects. It is also important to determine the role of saliva in microbial adhesion to obturator materials as well as develop materials that have a longer life span with surface characteristics that promote less microbial adhesion than current materials.
Topics: Biofilms; Dental Implants; Humans; Maxilla; Maxillary Neoplasms; Palatal Obturators
PubMed: 31665902
DOI: 10.1177/1055665619882555