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Journal of Microbiology (Seoul, Korea) Feb 2016In recent decades, many researchers have written numerous articles about microbial biofilms. Biofilm is a complex community of microorganisms and an example of bacterial... (Review)
Review
In recent decades, many researchers have written numerous articles about microbial biofilms. Biofilm is a complex community of microorganisms and an example of bacterial group behavior. Biofilm is usually considered a sessile mode of life derived from the attached growth of microbes to surfaces, and most biofilms are embedded in self-produced extracellular matrix composed of extracellular polymeric substances (EPSs), such as polysaccharides, extracellular DNAs (eDNA), and proteins. Dispersal, a mode of biofilm detachment indicates active mechanisms that cause individual cells to separate from the biofilm and return to planktonic life. Since biofilm cells are cemented and surrounded by EPSs, dispersal is not simple to do and many researchers are now paying more attention to this active detachment process. Unlike other modes of biofilm detachment such as erosion or sloughing, which are generally considered passive processes, dispersal occurs as a result of complex spatial differentiation and molecular events in biofilm cells in response to various environmental cues, and there are many biological reasons that force bacterial cells to disperse from the biofilms. In this review, we mainly focus on the spatial differentiation of biofilm that is a prerequisite for dispersal, as well as environmental cues and molecular events related to the biofilm dispersal. More specifically, we discuss the dispersal-related phenomena and mechanisms observed in Pseudomonas aeruginosa, an important opportunistic human pathogen and representative model organism for biofilm study.
Topics: Biofilms; Environmental Exposure; Gene Expression Regulation, Bacterial; Pseudomonas aeruginosa
PubMed: 26832663
DOI: 10.1007/s12275-016-5528-7 -
International Journal of Medical... Dec 2017Studies on biofilm related infections are gaining prominence owing to their involvement in majority of clinical infections. Biofilm, considered as a generic mechanism... (Review)
Review
Studies on biofilm related infections are gaining prominence owing to their involvement in majority of clinical infections. Biofilm, considered as a generic mechanism for survival used by pathogenic as well as non-pathogenic microorganisms, involves surface attachment and growth of heterogeneous cells encapsulated within a matrix. The matrix provides ecological niche where partnership of cells endows a community like behaviour that not only enables the cohort to survive local microenvironment stress but also channelizes them to evolve, disseminate and cause resurgence of infections. In this mini-review we highlight the mechanisms used by microbes to develop and sustain biofilms, including the influence of the microbiota. Several strategies to target biofilms have been validated on certain groups of microorganisms and these basically target different stages in the life cycle of biofilm, however comprehensive methods to target microbial biofilms are relatively unknown. In the backdrop of recent reports suggesting that biofilms can harbour multiple species of organisms, we need to relook and devise newer strategies against biofilms. Effective anti-biofilm strategies cannot be confined to a single methodology that can disrupt one pathway but should simultaneously target the various routes adopted by the microorganisms for survival within their ecosystem. An overview of the currently available drugs, their mode of action, genomic targets and translational therapies against biofilm related infection are discussed.
Topics: Bacterial Adhesion; Bacterial Physiological Phenomena; Biofilms; Humans; Microbial Interactions; Microbial Viability
PubMed: 28950999
DOI: 10.1016/j.ijmm.2017.09.016 -
NPJ Biofilms and Microbiomes May 2022The increasing awareness of the significance of microbial biofilms across different sectors is continuously revealing new areas of opportunity in the development of... (Review)
Review
The increasing awareness of the significance of microbial biofilms across different sectors is continuously revealing new areas of opportunity in the development of innovative technologies in translational research, which can address their detrimental effects, as well as exploit their benefits. Due to the extent of sectors affected by microbial biofilms, capturing their real financial impact has been difficult. This perspective highlights this impact globally, based on figures identified in a recent in-depth market analysis commissioned by the UK's National Biofilms Innovation Centre (NBIC). The outputs from this analysis and the workshops organised by NBIC on its research strategic themes have revealed the breath of opportunities for translational research in microbial biofilms. However, there are still many outstanding scientific and technological challenges which must be addressed in order to catalyse these opportunities. This perspective discusses some of these challenges.
Topics: Biofilms
PubMed: 35618743
DOI: 10.1038/s41522-022-00306-y -
Biotechnology Advances Nov 2017The discovery of direct extracellular electron transfer offers an alternative to the traditional understanding of diffusional electron exchange via small molecules. The... (Review)
Review
The discovery of direct extracellular electron transfer offers an alternative to the traditional understanding of diffusional electron exchange via small molecules. The establishment of electronic connections between electron donors and acceptors in microbial communities is critical to electron transfer via electrical currents. These connections are facilitated through conductivity associated with various microbial aggregates. However, examination of conductivity in microbial samples is still in its relative infancy and conceptual models in terms of conductive mechanisms are still being developed and debated. The present review summarizes the fundamental understanding of electrical conductivity in microbial aggregates (e.g. biofilms, granules, consortia, and multicellular filaments) highlighting recent findings and key discoveries. A greater understanding of electrical conductivity in microbial aggregates could facilitate the survey for additional microbial communities that rely on direct extracellular electron transfer for survival, inform rational design towards the aggregates-based production of bioenergy/bioproducts, and inspire the construction of new synthetic conductive polymers.
Topics: Bacteria; Biofilms; Electric Conductivity; Electron Transport; Microbial Consortia
PubMed: 28768145
DOI: 10.1016/j.biotechadv.2017.07.010 -
Drugs Oct 2019Biofilm-growing cells show an enhanced antimicrobial tolerance with respect to the same cells growing in a free-floating way. This is due to physical or chemical... (Review)
Review
Biofilm-growing cells show an enhanced antimicrobial tolerance with respect to the same cells growing in a free-floating way. This is due to physical or chemical diffusion barriers and increased transfer of resistance markers. Thus, tissue- and medical device-related biofilms can be considered among the leading sources of antibiotic treatment failure, causing many of the deadliest chronic infections afflicting humans nowadays. To find a satisfying way to counteract this major health threat, a great effort has been made in recent years to develop safe, effective and fast-acting anti-biofilm strategies. In this review, we summarise and evaluate the most promising tools and molecules that have demonstrated their ability to modulate steps involved in biofilm formation or to disperse pre-formed biofilms, without conferring evolutionary pressure to microorganisms.
Topics: Anti-Bacterial Agents; Biofilms; Humans; Infections
PubMed: 31468316
DOI: 10.1007/s40265-019-01184-z -
World Journal of Microbiology &... Apr 2022Heavy metal pollution due to excessive use of chemical fertilizers (CF) causes major damage to the environment. Microbial biofilms, closely associated with the...
Heavy metal pollution due to excessive use of chemical fertilizers (CF) causes major damage to the environment. Microbial biofilms, closely associated with the rhizosphere can remediate heavy metal-contaminated soil by reducing plant toxicity. Thus, this study was undertaken to examine the remedial effects of microbial biofilms against contaminated heavy metals. Fungi and bacteria isolated from soil were screened for their tolerance against Cd, Pb, and Zn. Three bacterial and two fungal isolates were selected upon the tolerance index (TI) percentage. Fungal-bacterial biofilms (FBBs) were developed with the most tolerant isolates and were further screened for their bioremediation capabilities against heavy metals. The best biofilm was evaluated for its rhizoremediation capability with different CF combinations using a pot experiment conducted under greenhouse conditions with potatoes. Significantly (P < 0.05), the highest metal removal percentage was observed in Trichoderma harzianum and Bacillus subtilis biofilm under in situ conditions. When compared to the 100% recommended CF, the biofilm with 50% of the recommended CF (50CB) significantly (P < 0.05) reduced soil available Pb by 77%, Cd by 78% and Zn by 62%. In comparison to initial soil, it was 73%, 76%, and 57% lower of Pb, Cd, and Zn, respectively. In addition, 50CB treatment significantly (P < 0.05) reduced the metal penetration into the tuber tissues in comparison with 100 C. Thus, the function of the developed FBB with T. harzianum-B. subtilis can be used as a potential solution to remediate soil polluted with Pb Cd and Zn metal contaminants.
Topics: Bacteria; Biodegradation, Environmental; Biofilms; Fungi; Metals, Heavy; Soil; Soil Pollutants
PubMed: 35380298
DOI: 10.1007/s11274-022-03267-8 -
Biofouling Jul 2021Microbial biofilms are difficult to control due to the limited accessibility that antimicrobial drugs and chemicals have to the entrapped inner cells. The extracellular... (Review)
Review
Microbial biofilms are difficult to control due to the limited accessibility that antimicrobial drugs and chemicals have to the entrapped inner cells. The extracellular matrix, binds water, contributes to altered cell physiology within biofilms and act as a barrier for most antiproliferative molecules. Thus, new strategies need to be developed to overcome biofilm vitality. In this review, based on 223 documents, the advantages, recommendations, and limitations of using bacteriophages as 'biofilm predators' are presented. The plausibility of using phages (bacteriophages and mycoviruses) to control biofilms grown in different environments is also discussed. The topics covered here include recent historical experiences in biofilm control/eradication using phages in medicine, dentistry, veterinary, and food industries, the pros and cons of their use, and the development of microbial resistance/immunity to such viruses.
Topics: Bacteriophages; Biofilms
PubMed: 34304662
DOI: 10.1080/08927014.2021.1955866 -
Journal of Bacteriology Oct 2016The advent of microscale technologies, such as microfluidics, has revolutionized many areas of biology yet has only recently begun to impact the field of bacterial... (Review)
Review
The advent of microscale technologies, such as microfluidics, has revolutionized many areas of biology yet has only recently begun to impact the field of bacterial biofilms. By enabling accurate control and manipulation of physical and chemical conditions, these new microscale approaches afford the ability to combine important features of natural and artificial microbial habitats, such as fluid flow and ephemeral nutrient sources, with an unprecedented level of flexibility and quantification. Here, we review selected case studies to exemplify this potential, discuss limitations, and suggest that this approach opens new vistas into biofilm research over traditional setups, allowing us to expand our understanding of the formation and consequences of biofilms in a broad range of environments and applications.
Topics: Bacterial Adhesion; Biofilms; Environment; Microfluidic Analytical Techniques; Time Factors
PubMed: 27274032
DOI: 10.1128/JB.00118-16 -
Applied Biochemistry and Biotechnology Sep 2023Heavy metal pollution caused due to various industrial and mining activities poses a serious threat to all forms of life in the environment because of the persistence... (Review)
Review
Heavy metal pollution caused due to various industrial and mining activities poses a serious threat to all forms of life in the environment because of the persistence and toxicity of metal ions. Microbial-mediated bioremediation including microbial biofilms has received significant attention as a sustainable tool for heavy metal removal as it is considered safe, effective, and feasible. The biofilm matrix is dynamic, having microbial cells as major components with constantly changing and evolving microenvironments. This review summarizes the bioremediation potential of bacterial biofilms for different metal ions. The composition and mechanism of biofilm formation along with interspecies communication among biofilm-forming bacteria have been discussed. The interaction of biofilm-associated microbes with heavy metals takes place through a variety of mechanisms. These include biosorption and bioaccumulation in which the microbes interact with the metal ions leading to their conversion from a highly toxic form to a less toxic form. Such interactions are facilitated via the negative charge of the extracellular polymeric substances on the surface of the biofilm with the positive charge of the metal ions and the high cell densities and high concentrations of cell-cell signaling molecules within the biofilm matrix. Furthermore, the impact of the anodic and cathodic redox potentials in a bioelectrochemical system (BES) for the reduction, removal, and recovery of numerous heavy metal species provides an interesting insight into the bacterial biofilm-mediated bioelectroremediation process. The review concludes that biofilm-linked bioremediation is a viable option for the mitigation of heavy metal pollution in water and ecosystem recovery.
Topics: Ecosystem; Biodegradation, Environmental; Metals, Heavy; Bacteria; Biofilms
PubMed: 36576654
DOI: 10.1007/s12010-022-04276-x -
Journal of Applied Microbiology May 2020As bacteria aggregate and form biofilms on surfaces in the human body such as tissues, indwelling medical devices, dressings and implants, they can cause a significant... (Review)
Review
As bacteria aggregate and form biofilms on surfaces in the human body such as tissues, indwelling medical devices, dressings and implants, they can cause a significant health risk. Bacterial biofilms possess altered phenotypes: physical features that facilitate antibiotic resistance and evasion of the host immune response. Since metabolic and physical factors contribute to biofilm maturation and persistence, an objective in antibiofilm therapy is to target these factors to deliver innovative approaches for solving these important health problems. Currently, there is little research on the direct immunological effects resulting from the introduction of foreign components to the body pertaining to biofilm inhibition methods. Detailed research involving animal models is necessary to better understand the biological side effects of synthetic peptides, genetically modified bacteriophages and isolated proteins and any resistance that may develop from these approaches.
Topics: Animals; Anti-Bacterial Agents; Bacterial Infections; Biofilms; Biological Products; Drug Resistance, Microbial; Humans; Immune Evasion
PubMed: 31618796
DOI: 10.1111/jam.14491