51
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Jana S, Charlton SGV, Eland LE, Burgess JG, Wipat A, Curtis TP, Chen J. Nonlinear rheological characteristics of single species bacterial biofilms. NPJ Biofilms Microbiomes 2020; 6:19. [PMID: 32286319 PMCID: PMC7156450 DOI: 10.1038/s41522-020-0126-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 03/09/2020] [Indexed: 12/15/2022] Open
Abstract
Bacterial biofilms in natural and artificial environments perform a wide array of beneficial or detrimental functions and exhibit resistance to physical as well as chemical perturbations. In dynamic environments, where periodic or aperiodic flows over surfaces are involved, biofilms can be subjected to large shear forces. The ability to withstand these forces, which is often attributed to the resilience of the extracellular matrix. This attribute of the extracellular matrix is referred to as viscoelasticity and is a result of self-assembly and cross-linking of multiple polymeric components that are secreted by the microbes. We aim to understand the viscoelastic characteristic of biofilms subjected to large shear forces by performing Large Amplitude Oscillatory Shear (LAOS) experiments on four species of bacterial biofilms: Bacillus subtilis, Comamonas denitrificans, Pseudomonas fluorescens and Pseudomonas aeruginosa. We find that nonlinear viscoelastic measures such as intracycle strain stiffening and intracycle shear thickening for each of the tested species, exhibit subtle or distinct differences in the plot of strain amplitude versus frequency (Pipkin diagram). The biofilms also exhibit variability in the onset of nonlinear behaviour and energy dissipation characteristics, which could be a result of heterogeneity of the extracellular matrix constituents of the different biofilms. The results provide insight into the nonlinear rheological behaviour of biofilms as they are subjected to large strains or strain rates; a situation that is commonly encountered in nature, but rarely investigated.
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Affiliation(s)
- Saikat Jana
- School of Biomedical Sciences, University of Leeds, Leeds, UK.
- School of Engineering, Newcastle University, Newcastle Upon Tyne, UK.
| | | | - Lucy E Eland
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, UK
| | - J Grant Burgess
- School of Natural & Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Anil Wipat
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, UK
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle Upon Tyne, UK
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle Upon Tyne, UK.
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52
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Zhu Y, Li JJ, Reng J, Wang S, Zhang R, Wang B. Global trends of Pseudomonas aeruginosa biofilm research in the past two decades: A bibliometric study. Microbiologyopen 2020; 9:1102-1112. [PMID: 32120451 PMCID: PMC7294304 DOI: 10.1002/mbo3.1021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022] Open
Abstract
Pseudomonas aeruginosa biofilm formation is a primary cause of chronic infections. This has been a highly active area of research over the past two decades due to causing high mortality risks in immunocompromised patients. This study evaluates global trends in the dynamic and rapidly evolving field of P. aeruginosa biofilm research through bibliometric and visualized analyses. Publications from 1994 to 2018 on P. aeruginosa biofilm research were retrieved from Web of Science, Scopus, and PubMed, and their bibliometric data were systematically studied. The VOSviewer software was used to conduct global analyses of bibliographic coupling, coauthorship, cocitation, and co-occurrence. A total of 9,527 publications were included in this study. The overall number of publications and research interest in the field displayed a strongly rising trend. The USA made the greatest contributions to the field, with the highest h-index and number of citations compared with other countries, while Denmark had the highest average citation per publication. The Journal of Bacteriology had the highest number of publications in the field, while the University of Copenhagen was the institution with the highest contribution influence. Co-occurrence network maps revealed that the most prominent topics in P. aeruginosa biofilm research were mechanistic studies, in vitro/in vivo studies, and biofilm formation studies. Pseudomonas aeruginosa biofilms constitute a dynamic research area in microbiology with increasing global research interest. Future studies will likely focus on investigating the mechanisms of biofilm formation to solve infection-associated clinical problems.
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Affiliation(s)
- Yuanyuan Zhu
- Department of PharmacyShanxi Medical University Second Affiliated HospitalTaiyuanChina
| | - Jiao Jiao Li
- Kolling InstituteUniversity of SydneySydneyNSWAustralia
| | - Jian Reng
- Department of PharmacyShanxi Medical University Second Affiliated HospitalTaiyuanChina
| | - Siyang Wang
- Department of PharmacyShanxi Medical University Second Affiliated HospitalTaiyuanChina
| | - Ruiqing Zhang
- Department of PharmacyShanxi Medical University Second Affiliated HospitalTaiyuanChina
| | - Bin Wang
- Department of OrthopaedicShanxi Medical University Second Affiliated HospitalTaiyuanChina
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53
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Li Y, Yang G, Ren Y, Shi L, Ma R, van der Mei HC, Busscher HJ. Applications and Perspectives of Cascade Reactions in Bacterial Infection Control. Front Chem 2020; 7:861. [PMID: 31970146 PMCID: PMC6960124 DOI: 10.3389/fchem.2019.00861] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022] Open
Abstract
Cascade reactions integrate two or more reactions, of which each subsequent reaction can only start when the previous reaction step is completed. Employing natural substrates in the human body such as glucose and oxygen, cascade reactions can generate reactive oxygen species (ROS) to kill tumor cells, but cascade reactions may also have potential as a direly needed, novel bacterial infection-control strategy. ROS can disintegrate the EPS matrix of infectious biofilm, disrupt bacterial cell membranes, and damage intra-cellular DNA. Application of cascade reactions producing ROS as a new infection-control strategy is still in its infancy. The main advantages for infection-control cascade reactions include the fact that they are non-antibiotic based and induction of ROS resistance is unlikely. However, the amount of ROS generated is generally low and antimicrobial efficacies reported are still far <3-4 log units necessary for clinical efficacy. Increasing the amounts of ROS generated by adding more substrate bears the risk of collateral damage to tissue surrounding an infection site. Collateral tissue damage upon increasing substrate concentrations may be prevented by locally increasing substrate concentrations, for instance, using smart nanocarriers. Smart, pH-responsive nanocarriers can self-target and accumulate in infectious biofilms from the blood circulation to confine ROS production inside the biofilm to yield long-term presence of ROS, despite the short lifetime (nanoseconds) of individual ROS molecules. Increasing bacterial killing efficacies using cascade reaction components containing nanocarriers constitutes a first, major challenge in the development of infection-control cascade reactions. Nevertheless, their use in combination with clinical antibiotic treatment may already yield synergistic effects, but this remains to be established for cascade reactions. Furthermore, specific patient groups possessing elevated levels of endogenous substrate (for instance, diabetic or cancer patients) may benefit from the use of cascade reaction components containing nanocarriers.
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Affiliation(s)
- Yuanfeng Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, China.,Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Guang Yang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, China.,Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Yijin Ren
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Linqi Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, China
| | - Rujiang Ma
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, China
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Henk J Busscher
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, China.,Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
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54
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Cao Y, Naseri M, He Y, Xu C, Walsh LJ, Ziora ZM. Non-antibiotic antimicrobial agents to combat biofilm-forming bacteria. J Glob Antimicrob Resist 2019; 21:445-451. [PMID: 31830536 DOI: 10.1016/j.jgar.2019.11.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022] Open
Abstract
Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bacteria in biofilms are less susceptible to antibiotics compared with their free-floating state, as biofilms impair antibiotic penetration. To obviate this challenge, non-antibiotic antimicrobial agents are needed. This review describes two classes of these agents, namely antimicrobial nanoparticles and antimicrobial peptides. Applications of these antimicrobials in the food industry and medical applications are discussed, and the directions for future research are highlighted.
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Affiliation(s)
- Yuxue Cao
- School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Australia; School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Mahdi Naseri
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, VIC 3800, Australia
| | - Yan He
- School of Dentistry, The University of Queensland, QLD 4006, Australia; Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital and Harvard School of Dental Medicine, Boston, MA 02114, USA.
| | - Chun Xu
- School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Laurence J Walsh
- School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Zyta M Ziora
- Institute for Molecular Bioscience, The University of Queensland, QLD 4072, Australia.
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55
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Streptomycin mediated biofilm inhibition and suppression of virulence properties in Pseudomonas aeruginosa PAO1. Appl Microbiol Biotechnol 2019; 104:799-816. [PMID: 31820066 DOI: 10.1007/s00253-019-10190-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/09/2019] [Accepted: 10/07/2019] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa is known as an opportunistic pathogen whose one of the antibiotic resistance mechanisms includes biofilm formation and virulence factor production. The present study showed that the sub-minimum inhibitory concentration (sub-MIC) of streptomycin inhibited the formation of biofilm and eradicated the established mature biofilm. Streptomycin at sub-MIC was also capable of inhibiting biofilm formation on the urinary catheters. In addition, the sub-MIC of streptomycin attenuated the bacterial virulence properties as confirmed by both phenotypic and gene expression studies. The optimal conditions for streptomycin to perform anti-biofilm and anti-virulence activities were proposed as alkaline TSB media (pH 7.9) at 35 °C. However, sub-MIC of streptomycin also exhibited a comparative anti-biofilm efficacy in LB media at similar pH level and temperature. Furthermore, this condition also improved the biofilm inhibition and eradication properties of streptomycin, tobramycin and tetracycline towards the biofilm formed by a clinical isolate of P. aeruginosa. Findings from the present study provide an important insight for further studies on the mechanisms of biofilm inhibition and dispersion of pre-existing biofilm by streptomycin as well as tobramycin and tetracycline under a specific culture environment.
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56
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Abstract
Biofilms are surface-associated bacterial communities that play both beneficial and harmful roles in nature, medicine, and industry. Tolerant and persister cells are thought to underlie biofilm-related bacterial recurrence in medical and industrial contexts. Here, we review recent progress aimed at understanding the mechanical features that drive biofilm resilience and the biofilm formation process at single-cell resolution. We discuss findings regarding mechanisms underlying bacterial tolerance and persistence in biofilms and how these phenotypes are linked to antibiotic resistance. New strategies for combatting tolerance and persistence in biofilms and possible methods for biofilm eradication are highlighted to inspire future development.
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57
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Bonyadi SZ, Atten M, Dunn AC. Self-regenerating compliance and lubrication of polyacrylamide hydrogels. SOFT MATTER 2019; 15:8728-8740. [PMID: 31553022 DOI: 10.1039/c9sm01607d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Pristine hydrogel surfaces typically have low friction, which is controlled by composition, slip speeds, and immediate slip history. The stiffness of such samples is typically measured with bulk techniques, and is assumed to be homogeneous at the surface. While the surface properties of homogeneous hydrogel samples are generally controlled by composition, the surface also interfaces with the open bath, which distinguishes it from the bulk. In this work, we disrupt as-molded polyacrylamide surfaces with abrasive wear and connect the effects on the surface stiffness and lubrication to the wear events. At both the nanoscale and the microscale, quasistatic indentations reveal a stiffer surface by up to two times following wear events, even considering roughness. Longitudinal experiments with a series of wear episodes interposed with periods of re-equilibration show that increased stiffness is reversible: more compliant surfaces regenerate within 24 hours. The timescale suggests an osmotic swelling mechanism, and we postulate that abrasive wear removes a swollen surface layer, revealing the stiffer bulk. The newly-revealed bulk becomes the surface, which re-swells over time. We quantify the effects on the self-lubricating ability of these surfaces following abrasive wear using micro-tribometry. The lubrication curve shows that robust low friction is maintained, and that the friction becomes less dependent upon the sliding speed. The unique ability of these materials to regenerate swollen surfaces and maintain robust low friction following abrasive wear is promising for designing their slip behavior into aqueous soft robotics components or biomedicine applications.
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Affiliation(s)
- Shabnam Z Bonyadi
- Department of Mechanical Science & Engineering, University of Illinois at Urbana-Champaign, MechSE @ UIUC, 1206 W Green St, MC 244, Urbana, IL 61801, USA.
| | - Michael Atten
- Department of Mechanical Science & Engineering, University of Illinois at Urbana-Champaign, MechSE @ UIUC, 1206 W Green St, MC 244, Urbana, IL 61801, USA.
| | - Alison C Dunn
- Department of Mechanical Science & Engineering, University of Illinois at Urbana-Champaign, MechSE @ UIUC, 1206 W Green St, MC 244, Urbana, IL 61801, USA.
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58
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Røder HL, Olsen NMC, Whiteley M, Burmølle M. Unravelling interspecies interactions across heterogeneities in complex biofilm communities. Environ Microbiol 2019; 22:5-16. [DOI: 10.1111/1462-2920.14834] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/15/2019] [Accepted: 10/17/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Henriette L. Røder
- Section of Microbiology, Department of BiologyUniversity of Copenhagen Copenhagen Denmark
| | - Nanna M. C. Olsen
- Section of Microbiology, Department of BiologyUniversity of Copenhagen Copenhagen Denmark
| | - Marvin Whiteley
- School of Biological SciencesGeorgia Institute of Technology, Atlanta Georgia USA
- Emory‐Children's Cystic Fibrosis Center, Atlanta Georgia USA
- Center for Microbial Dynamics and InfectionGeorgia Institute of Technology, Atlanta Georgia USA
| | - Mette Burmølle
- Section of Microbiology, Department of BiologyUniversity of Copenhagen Copenhagen Denmark
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59
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Aravinda Narayanan R, Ahmed A. Arrested fungal biofilms as low-modulus structural bio-composites: Water holds the key. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:134. [PMID: 31643003 DOI: 10.1140/epje/i2019-11899-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Biofilms are self-assembling structures consisting of rigid microbial cells embedded in a soft biopolymeric extracellular matrix (ECM), and have been commonly viewed as being detrimental to health and equipment. In this work, we show that biofilms formed by a non-pathogenic fungus Neurospora discreta, are fungal bio-composites (FBCs) that can be directed to self-organize through active stresses to achieve specific properties. We induced active stresses by systematically varying the agitation rate during the growth of FBCs. By growing FBCs that are strong enough to be conventionally tensile loaded, we find that as agitation rate increases, the elongation strain at which the FBCs break, increases linearly, and their elastic modulus correspondingly decreases. Using results from microstructural imaging and thermogravimetry, we rationalize that agitation increases the production of ECM, which concomitantly increases the water content of agitated FBCs up to 250% more than un-agitated FBCs. Water held in the nanopores of the ECM acts a plasticizer and controls the ductility of FBCs in close analogy with polyelectrolyte complexes. This paradigm shift in viewing biofilms as bio-composites opens up the possibility for their use as sustainable, biodegradable, low-modulus structural materials.
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Affiliation(s)
- R Aravinda Narayanan
- Department of Physics, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, 500078, Hyderabad, India.
| | - Asma Ahmed
- School of Human and Life Sciences, Canterbury Christ Church University, North Holmes Road, CT1 1QU, Canterbury, UK
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60
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Luminescent Nanosensors for Ratiometric Monitoring of Three-Dimensional Oxygen Gradients in Laboratory and Clinical Pseudomonas aeruginosa Biofilms. Appl Environ Microbiol 2019; 85:AEM.01116-19. [PMID: 31420335 DOI: 10.1128/aem.01116-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/09/2019] [Indexed: 01/08/2023] Open
Abstract
Bacterial biofilms can form persistent infections on wounds and implanted medical devices and are associated with many chronic diseases, such as cystic fibrosis. These infections are medically difficult to treat, as biofilms are more resistant to antibiotic attack than their planktonic counterparts. An understanding of the spatial and temporal variation in the metabolism of biofilms is a critical component toward improved biofilm treatments. To this end, we developed oxygen-sensitive luminescent nanosensors to measure three-dimensional (3D) oxygen gradients, an application of which is demonstrated here with Pseudomonas aeruginosa biofilms. The method was applied here and improves on traditional one-dimensional (1D) methods of measuring oxygen profiles by investigating the spatial and temporal variation of oxygen concentration when biofilms are challenged with antibiotic attack. We observed an increased oxygenation of biofilms that was consistent with cell death from comparisons with antibiotic kill curves for PAO1. Due to the spatial and temporal nature of our approach, we also identified spatial and temporal inhomogeneities in the biofilm metabolism that are consistent with previous observations. Clinical strains of P. aeruginosa subjected to similar interrogation showed variations in resistance to colistin and tobramycin, which are two antibiotics commonly used to treat P. aeruginosa infections in cystic fibrosis patients.IMPORTANCE Biofilm infections are more difficult to treat than planktonic infections for a variety of reasons, such as decreased antibiotic penetration. Their complex structure makes biofilms challenging to study without disruption. To address this limitation, we developed and demonstrated oxygen-sensitive luminescent nanosensors that can be incorporated into biofilms for studying oxygen penetration, distribution, and antibiotic efficacy-demonstrated here with our sensors monitoring antibiotic impacts on metabolism in biofilms formed from clinical isolates. The significance of our research is in demonstrating not only a nondisruptive method for imaging and measuring oxygen in biofilms but also that this nanoparticle-based sensing platform can be modified to measure many different ions and small molecule analytes.
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61
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Charlton SGV, White MA, Jana S, Eland LE, Jayathilake PG, Burgess JG, Chen J, Wipat A, Curtis TP. Regulating, Measuring, and Modeling the Viscoelasticity of Bacterial Biofilms. J Bacteriol 2019; 201:e00101-19. [PMID: 31182499 PMCID: PMC6707926 DOI: 10.1128/jb.00101-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Biofilms occur in a broad range of environments under heterogeneous physicochemical conditions, such as in bioremediation plants, on surfaces of biomedical implants, and in the lungs of cystic fibrosis patients. In these scenarios, biofilms are subjected to shear forces, but the mechanical integrity of these aggregates often prevents their disruption or dispersal. Biofilms' physical robustness is the result of the multiple biopolymers secreted by constituent microbial cells which are also responsible for numerous biological functions. A better understanding of the role of these biopolymers and their response to dynamic forces is therefore crucial for understanding the interplay between biofilm structure and function. In this paper, we review experimental techniques in rheology, which help quantify the viscoelasticity of biofilms, and modeling approaches from soft matter physics that can assist our understanding of the rheological properties. We describe how these methods could be combined with synthetic biology approaches to control and investigate the effects of secreted polymers on the physical properties of biofilms. We argue that without an integrated approach of the three disciplines, the links between genetics, composition, and interaction of matrix biopolymers and the viscoelastic properties of biofilms will be much harder to uncover.
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Affiliation(s)
- Samuel G V Charlton
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael A White
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Saikat Jana
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lucy E Eland
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - J Grant Burgess
- School of Natural & Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anil Wipat
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
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62
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Sankaran J, Karampatzakis A, Rice SA, Wohland T. Quantitative imaging and spectroscopic technologies for microbiology. FEMS Microbiol Lett 2019; 365:4953418. [PMID: 29718275 DOI: 10.1093/femsle/fny075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/23/2018] [Indexed: 12/17/2022] Open
Abstract
Light microscopy has enabled the observation of the structure and organisation of biofilms. Typically, the contrast in an image obtained from light microscopy is given by the time-averaged intensity that is effective in visualising the overall structure. Technological advancements in light microscopy have led to the creation of techniques that not only provide a static intensity image of the biofilm, but also enable one to quantify various dynamic physicochemical properties of biomolecules in microbial biofilms. Such light microscopy-based techniques can be grouped into two main classes, those that are based on luminescence and those that are based on scattering. Here, we review the fundamentals and applications of luminescence and scattering-based techniques, specifically, fluorescence lifetime imaging, Förster resonance energy transfer, fluorescence correlation spectroscopy, fluorescence recovery after photobleaching, single-particle tracking, transient state imaging, and Brillouin and Raman microscopy. These techniques provide information about the abundance, interactions and mobility of various molecules in the biofilms and also properties of the local microenvironment at optical resolution. Further, one could use any of these techniques to probe the real-time changes in these physical parameters upon the addition of external agents or at different stages during the growth of biofilms.
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Affiliation(s)
- Jagadish Sankaran
- Departments of Biological Sciences and Chemistry, National University of Singapore, Singapore 117558, Singapore.,Centre for BioImaging Sciences, National University of Singapore, Singapore 117557, Singapore
| | - Andreas Karampatzakis
- Centre for BioImaging Sciences, National University of Singapore, Singapore 117557, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering and School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.,ithree Institute, University of Technology, Sydney 2007, Australia
| | - Thorsten Wohland
- Departments of Biological Sciences and Chemistry, National University of Singapore, Singapore 117558, Singapore.,Centre for BioImaging Sciences, National University of Singapore, Singapore 117557, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore
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63
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Dunsing V, Irmscher T, Barbirz S, Chiantia S. Purely Polysaccharide-Based Biofilm Matrix Provides Size-Selective Diffusion Barriers for Nanoparticles and Bacteriophages. Biomacromolecules 2019; 20:3842-3854. [DOI: 10.1021/acs.biomac.9b00938] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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64
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Hayta EN, Lieleg O. Biopolymer-enriched B. subtilis NCIB 3610 biofilms exhibit increased erosion resistance. Biomater Sci 2019; 7:4675-4686. [PMID: 31475697 DOI: 10.1039/c9bm00927b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The erosion resistance of bacterial biofilms can be a double-edged sword: it hampers the removal of undesired biofilms in biomedical settings, but it is necessary for beneficial biofilms to be used in aqueous environments for biotechnological applications. Whether or not a bacterial biofilm exhibits this material property depends on the bacterial species and the detailed composition of the biofilm matrix. Here, we demonstrate how the erosion resistance of B. subtilis NCIB 3610 biofilms can be enhanced by integrating foreign (bio)polymers into the matrix during biofilm growth. As a result of this artificial macromolecule addition, the engineered biofilm colonies show changes in their surface topography which, in turn, cause an alteration in the mode of surface superhydrophobicity. Surprisingly, the viscoelastic properties and permeability of the biofilms towards antibiotics remain unaffected. The method introduced here may present a promising strategy for engineering beneficial biofilms such, that they become more stable towards shear forces caused by flowing water but, at the same time, remain permeable to nutrients or other molecules.
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Affiliation(s)
- Elif N Hayta
- Munich School of Bioengineering and Department of Mechanical Engineering, Technical University of Munich, 85748 Garching, Germany.
| | - Oliver Lieleg
- Munich School of Bioengineering and Department of Mechanical Engineering, Technical University of Munich, 85748 Garching, Germany.
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65
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Araújo GRDS, Viana NB, Gómez F, Pontes B, Frases S. The mechanical properties of microbial surfaces and biofilms. ACTA ACUST UNITED AC 2019; 5:100028. [PMID: 32743144 PMCID: PMC7389442 DOI: 10.1016/j.tcsw.2019.100028] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/13/2022]
Abstract
Microbes can modify their surface structure as an adaptive mechanism for survival and dissemination in the environment or inside the host. Altering their ability to respond to mechanical stimuli is part of this adaptive process. Since the 1990s, powerful micromanipulation tools have been developed that allow mechanical studies of microbial cell surfaces, exploring little known aspects of their dynamic behavior. This review concentrates on the study of mechanical and rheological properties of bacteria and fungi, focusing on their cell surface dynamics and biofilm formation.
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Affiliation(s)
- Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Nathan B Viana
- Laboratório de Pinças Óticas (LPO-COPEA), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Fran Gómez
- Laboratório de Pinças Óticas (LPO-COPEA), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bruno Pontes
- Laboratório de Pinças Óticas (LPO-COPEA), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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66
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Cattò C, Cappitelli F. Testing Anti-Biofilm Polymeric Surfaces: Where to Start? Int J Mol Sci 2019; 20:E3794. [PMID: 31382580 PMCID: PMC6696330 DOI: 10.3390/ijms20153794] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.
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Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
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67
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Abstract
Food and beverage industries operate their production units under stringent hygiene standards to verify high-quality products. However, the presence of biofilms can cause hygienic problems in the industries in the case of pathogenic organisms. Microorganisms can form biofilms, which are resistant to cleaning and disinfection. Microorganisms in biofilms are closely packed in a matrix that acts as a barrier to cleaning and disinfection. Biofilms are observed in processing equipment and open surfaces, resulting in food safety problems or weakening of production efficiency. This review provides a recap of the biofouling process, including the production mechanisms and control techniques of microbial adhesion. Microbial adhesion and colonization are the sine qua non of the establishment of bacterial pathogenesis and this report focuses on their prevention.
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68
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Aiyer KS, Vijayakumar BS. An improvised microtiter dish biofilm assay for non-invasive biofilm detection on microbial fuel cell anodes and studying biofilm growth conditions. Braz J Microbiol 2019; 50:769-775. [PMID: 31104214 PMCID: PMC6863186 DOI: 10.1007/s42770-019-00091-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 05/04/2019] [Indexed: 10/26/2022] Open
Abstract
Microbial life is predominantly observed as biofilms, which are a sessile aggregation of microbial cells formed in response to stress conditions. The microtiter dish biofilm formation assay is one of the most important methods of studying biofilm formation. In this study, the assay has been improvised to allow easy detection of biofilm formation on different substrata. The method has then been used to study growth conditions that affect biofilm formation, viz., the effect of pH, temperature, shaking conditions, and the carbon source provided. Glass, cellulose acetate, and carbon cloth materials were used as substrata to study biofilm development under the above conditions. The method was then extended to determine biofilm formation on the anodes of a microbial fuel cell in order to study the effect of biofilm formation on power production. A high correlation was observed between biofilm formation and power density (r = 0.951). When the electrode containing a biofilm was replaced with another electrode without biofilm, the average power density dropped from 59.55 to 5.76 mW/m2. This method offers an easy way to study the suitability of different materials to support biofilm formation. Growth conditions determining biofilm formation can be studied using this method. This method also offers a non-invasive way to determine biofilm formation on anodes of microbial fuel cells and preserves the anode for further studies.
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Affiliation(s)
- Kartik S. Aiyer
- Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Puttaparthi, Andhra Pradesh 515134 India
| | - B. S. Vijayakumar
- Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Puttaparthi, Andhra Pradesh 515134 India
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69
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Horvat M, Pannuri A, Romeo T, Dogsa I, Stopar D. Viscoelastic response of Escherichia coli biofilms to genetically altered expression of extracellular matrix components. SOFT MATTER 2019; 15:5042-5051. [PMID: 31179461 DOI: 10.1039/c9sm00297a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
How the viscoelastic properties of the extracellular matrix affect the various biological functions conferred by biofilms is an important question in microbiology. In this study, the viscoelastic response of Escherichia coli biofilms to the genetically altered expression of extracellular matrix components was studied. Biofilms of the wild type E. coli MG1655 and its mutant strains producing different amounts of extracellular matrix components (curli, colanic acid, and poly-β-1,6-N-acetyl-d-glucosamine) were used to examine the viscoelastic behavior of biofilms grown at the solid-atmosphere interface. The results suggest that the presence of curli proteins dominates biofilm mechanical behavior. The rheological data indicate that the cohesive energy of the biofilm was the highest in the wild type strain. The results demonstrate the importance of extracellular matrix composition for biofilm mechanical properties. We propose that by genetically altering the expression of extracellular matrix polymers, bacteria are able to modulate the mechanical properties of their local environment in accordance with bulk environmental conditions.
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Affiliation(s)
- Maruša Horvat
- University of Ljubljana, Biotechnical Faculty, Chair of Microbiology, Department of Food Science and Technology, Večna pot 111, 1000 Ljubljana, Slovenia.
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70
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Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in the flowing and no-flowing microchannels. ACTA ACUST UNITED AC 2019; 46:855-868. [DOI: 10.1007/s10295-019-02161-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 03/05/2019] [Indexed: 01/12/2023]
Abstract
Abstract
Biofilm accumulation in porous media can cause pore plugging and change many of the physical properties of porous media. Engineering bioplugging may have significant applications for many industrial processes, while improved knowledge on biofilm accumulation in porous media at porescale in general has broad relevance for a range of industries as well as environmental and water research. The experimental results by means of microscopic imaging over a T-shape microchannel clearly show that increase in fluid velocity could facilitate biofilm growth, but that above a velocity threshold, biofilm detachment and inhibition of biofilm formation due to high shear stress were observed. High nutrient concentration prompts the biofilm growth; however, the generated biofilm displays a weak adhesive strength. This paper provides an overview of biofilm development in a hydrodynamic environment for better prediction and modelling of bioplugging processes associated with porous systems in petroleum industry, hydrogeology and water purification.
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71
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Enzyme responsive copolymer micelles enhance the anti-biofilm efficacy of the antiseptic chlorhexidine. Int J Pharm 2019; 566:329-341. [PMID: 31152793 DOI: 10.1016/j.ijpharm.2019.05.069] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/09/2019] [Accepted: 05/27/2019] [Indexed: 12/22/2022]
Abstract
Staphylococcal biofilms cause many infectious diseases and are highly tolerant to the effects of antimicrobials; this is partly due to the biofilm matrix, which acts as a physical barrier retarding the penetration and reducing susceptibility to antimicrobials, thereby decreasing successful treatment outcomes. In this study, both single and mixed micellar systems based on poly vinyl caprolactam (PCL)-polyethylene glycol (PEG) copolymers were optimised for delivery of chlorhexidine (CHX) to S. aureus, MRSA and S. epidermidis biofilms and evaluated for their toxicity using Caenorhabditis elegans. The respective polyethylene glycol (PEG) and poly vinyl caprolactam (PCL) structural components promoted stealth properties and enzymatic responsive release of CHX inside biofilms, leading to significantly enhanced penetration (56%) compared with free CHX and improving the efficacy against Staphylococcus aureus biofilms grown on an artificial dermis (2.4 log reduction of CFU). Mixing Soluplus-based micelles with Solutol further enhanced the CHX penetration (71%) and promoted maximum reduction in biofilm biomass (>60%). Nematodes-based toxicity assay showed micelles with no lethal effects as indicated by their high survival rate (100%) after 72 h exposure. This study thus demonstrated that bio-responsive carriers can be designed to deliver a poorly water-soluble antimicrobial agent and advance the control of biofilm associated infections.
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72
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Sharma D, Misba L, Khan AU. Antibiotics versus biofilm: an emerging battleground in microbial communities. Antimicrob Resist Infect Control 2019; 8:76. [PMID: 31131107 PMCID: PMC6524306 DOI: 10.1186/s13756-019-0533-3] [Citation(s) in RCA: 765] [Impact Index Per Article: 153.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/30/2019] [Indexed: 12/25/2022] Open
Abstract
Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.
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Affiliation(s)
- Divakar Sharma
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002 India
| | - Lama Misba
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002 India
| | - Asad U. Khan
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002 India
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73
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Current Status of In Vitro Models and Assays for Susceptibility Testing for Wound Biofilm Infections. Biomedicines 2019; 7:biomedicines7020034. [PMID: 31052271 PMCID: PMC6630351 DOI: 10.3390/biomedicines7020034] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/20/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022] Open
Abstract
Biofilm infections have gained recognition as an important therapeutic challenge in the last several decades due to their relationship with the chronicity of infectious diseases. Studies of novel therapeutic treatments targeting infections require the development and use of models to mimic the formation and characteristics of biofilms within host tissues. Due to the diversity of reported in vitro models and lack of consensus, this review aims to provide a summary of in vitro models currently used in research. In particular, we review the various reported in vitro models of Pseudomonas aeruginosa biofilms due to its high clinical impact in chronic wounds and in other chronic infections. We assess advances in in vitro models that incorporate relevant multispecies biofilms found in infected wounds, such as P. aeruginosa with Staphylococcus aureus, and additional elements such as mammalian cells, simulating fluids, and tissue explants in an attempt to better represent the physiological conditions found at an infection site. It is hoped this review will aid researchers in the field to make appropriate choices in their proposed studies with regards to in vitro models and methods.
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74
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Qi L, Christopher GF. Role of Flagella, Type IV Pili, Biosurfactants, and Extracellular Polymeric Substance Polysaccharides on the Formation of Pellicles by Pseudomonas aeruginosa. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5294-5304. [PMID: 30883129 DOI: 10.1021/acs.langmuir.9b00271] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microbial biofilms are viscoelastic materials formed by bacteria, which occur on solid surfaces, at liquid interfaces, or in free solution. Although solid surface biofilms have been widely studied, pellicles, biofilms at liquid interfaces, have had significantly less focus. In this work, interfacial shear rheology and scanning electron microscopy imaging are used to characterize how flagella, type IV pili, biosurfactants, and extracellular polymeric substance polysaccharides affect the formation of pellicles by Pseudomonas aeruginosa at an air/water interface. Pellicles still form with the loss of a single biological attachment mechanism, which is hypothesized to be due to surface tension-aided attachment. Changes in the surface structure of the pellicles are observed when changing both the function/structure of type IV pili, removing the flagella, or stopping the expression of biosurfactants. However, these changes do not appear to affect pellicle elasticity in a consistent way. Traits that affect adsorption and growth/spreading appear to affect pellicles in a manner consistent with literature results for solid surface biofilms; small differences are seen in attachment-related mechanisms, which may occur due to surface tension.
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Affiliation(s)
- Lingjuan Qi
- Department of Mechanical Engineering , Texas Tech University , Lubbock 79409 , United States
| | - Gordon F Christopher
- Department of Mechanical Engineering , Texas Tech University , Lubbock 79409 , United States
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75
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Liou HC, Sabba F, Packman AI, Wells G, Balogun O. Nondestructive characterization of soft materials and biofilms by measurement of guided elastic wave propagation using optical coherence elastography. SOFT MATTER 2019; 15:575-586. [PMID: 30601536 DOI: 10.1039/c8sm01902a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biofilms are soft multicomponent biological materials composed of microbial communities attached to surfaces. Despite the crucial relevance of biofilms to diverse industrial, medical, and environmental applications, the mechanical properties of biofilms are understudied. Moreover, most of the available techniques for the characterization of biofilm mechanical properties are destructive. Here, we detail a model-based approach developed to characterize the viscoelastic properties of soft materials and bacterial biofilms based on experimental data obtained using the nondestructive dynamic optical coherence elastography (OCE) technique. The model predicted the frequency- and geometry-dependent propagation velocities of elastic waves in a soft viscoelastic plate supported by a rigid substratum. Our numerical calculations suggest that the dispersion curves of guided waves recorded in thin soft plates by the dynamic OCE technique are dominated by guided waves, whose phase velocities depend on the viscoelastic properties and plate thickness. The numerical model was validated against experimental measurements in agarose phantom samples with different thicknesses and concentrations. The model was then used to interpret guided wave dispersion curves obtained by the OCE technique in bacterial biofilms developed in a rotating annular reactor, which allowed the quantitative characterization of biofilm shear modulus and viscosity. This study is the first to employ measurements of elastic wave propagation to characterize biofilms, and it provides a novel framework combining a theoretical model and an experimental approach for studying the relationship between the biofilm internal physical structure and mechanical properties.
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Affiliation(s)
- Hong-Cin Liou
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Fabrizio Sabba
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Aaron I Packman
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - George Wells
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Oluwaseyi Balogun
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA and Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
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76
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Pannekens M, Kroll L, Müller H, Mbow FT, Meckenstock RU. Oil reservoirs, an exceptional habitat for microorganisms. N Biotechnol 2018; 49:1-9. [PMID: 30502541 PMCID: PMC6323355 DOI: 10.1016/j.nbt.2018.11.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 01/21/2023]
Abstract
Water-containing parts within oil reservoirs extend the zone of biodegradation. Biodegradation is controlled by environmental factors. Proteobacteria and Euryarchaeota are ubiquitous in oil reservoirs over all temperature ranges. Biofilms as microbial adaption in oil reservoirs. Viruses as potential control for microbial activity and function.
Microorganisms are present in oil reservoirs around the world where they degrade oil and lead to changes in oil quality. Unfortunately, our knowledge about processes in deep oil reservoirs is limited due to the lack of undisturbed samples. In this review, we discuss the distribution of microorganisms at the oil-water transition zone as well as in water saturated parts of the oil leg and their possible physiological adaptations to abiotic and biotic ecological factors such as temperature, salinity and viruses. We show the importance of studying the water phase within the oil, because small water inclusions and pockets within the oil leg provide an exceptional habitat for microorganisms within a natural oil reservoir and concurrently enlarge the zone of oil biodegradation. Environmental factors such as temperature and salinity control oil biodegradation. Temperature determines the type of microorganisms which are able to inhabit the reservoir. Proteobacteria and Euryarchaeota, are ubiquitous in oil reservoirs over all temperature ranges, whereas some others are tied to specific temperatures. It is proposed that biofilm formation is the dominant way of life within oil reservoirs, enhancing nutrient uptake, syntrophic interactions and protection against environmental stress. Literature shows that viruses are abundant in oil reservoirs and the possible impact on microbial community composition due to control of microbial activity and function is discussed.
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Affiliation(s)
- Mark Pannekens
- University of Duisburg-Essen, Biofilm Centre, Universitätsstr. 5, 41451, Essen, Germany
| | - Lisa Kroll
- University of Duisburg-Essen, Biofilm Centre, Universitätsstr. 5, 41451, Essen, Germany
| | - Hubert Müller
- University of Duisburg-Essen, Biofilm Centre, Universitätsstr. 5, 41451, Essen, Germany
| | - Fatou Tall Mbow
- University of Duisburg-Essen, Biofilm Centre, Universitätsstr. 5, 41451, Essen, Germany
| | - Rainer U Meckenstock
- University of Duisburg-Essen, Biofilm Centre, Universitätsstr. 5, 41451, Essen, Germany.
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77
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Liu L, Wu R, Zhang J, Li P. Overexpression of luxS Promotes Stress Resistance and Biofilm Formation of Lactobacillus paraplantarum L-ZS9 by Regulating the Expression of Multiple Genes. Front Microbiol 2018; 9:2628. [PMID: 30483223 PMCID: PMC6240686 DOI: 10.3389/fmicb.2018.02628] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022] Open
Abstract
Probiotics have evoked great interest in the past years for their beneficial effects. The aim of this study was to investigate whether luxS overexpression promotes the stress resistance of Lactobacillus paraplantarum L-ZS9. Here we show that overexpression of luxS gene increased the production of autoinducer-2 (AI-2, quorum sensing signal molecule) by L. paraplantarum L-ZS9. At the same time, overexpression of luxS promoted heat-, bile salt-resistance and biofilm formation of the strain. RNAseq results indicated that multiple genes encoding transporters, membrane proteins, and transcriptional regulator were regulated by luxS. These results reveal a new role for LuxS in promoting stress resistance and biofilm formation of probiotic starter.
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Affiliation(s)
- Lei Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Functional Dairy, China Agricultural University, Beijing, China
| | - Ruiyun Wu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Functional Dairy, China Agricultural University, Beijing, China
| | - Jinlan Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Functional Dairy, China Agricultural University, Beijing, China
| | - Pinglan Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Functional Dairy, China Agricultural University, Beijing, China
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78
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Yan J, Moreau A, Khodaparast S, Perazzo A, Feng J, Fei C, Mao S, Mukherjee S, Košmrlj A, Wingreen NS, Bassler BL, Stone HA. Bacterial Biofilm Material Properties Enable Removal and Transfer by Capillary Peeling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1804153. [PMID: 30368924 PMCID: PMC8865467 DOI: 10.1002/adma.201804153] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/30/2018] [Indexed: 05/22/2023]
Abstract
Biofilms, surface-attached communities of bacterial cells, are a concern in health and in industrial operations because of persistent infections, clogging of flows, and surface fouling. Extracellular matrices provide mechanical protection to biofilm-dwelling cells as well as protection from chemical insults, including antibiotics. Understanding how biofilm material properties arise from constituent matrix components and how these properties change in different environments is crucial for designing biofilm removal strategies. Here, using rheological characterization and surface analyses of Vibrio cholerae biofilms, it is discovered how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Using insight gained from our measurements, a facile capillary peeling technology is developed to remove biofilms from surfaces or to transfer intact biofilms from one surface to another. It is shown that the findings are applicable to other biofilm-forming bacterial species and to multiple surfaces. Thus, the technology and the understanding that have been developed could potentially be employed to characterize and/or treat biofilm-related infections and industrial biofouling problems.
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Affiliation(s)
- Jing Yan
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Alexis Moreau
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Sepideh Khodaparast
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Antonio Perazzo
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Jie Feng
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Chenyi Fei
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Sheng Mao
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Sampriti Mukherjee
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
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79
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Teirlinck E, Xiong R, Brans T, Forier K, Fraire J, Van Acker H, Matthijs N, De Rycke R, De Smedt SC, Coenye T, Braeckmans K. Laser-induced vapour nanobubbles improve drug diffusion and efficiency in bacterial biofilms. Nat Commun 2018; 9:4518. [PMID: 30375378 PMCID: PMC6207769 DOI: 10.1038/s41467-018-06884-w] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 10/02/2018] [Indexed: 02/07/2023] Open
Abstract
Hindered penetration of antibiotics through biofilms is one of the reasons for the alarming increase in bacterial tolerance to antibiotics. Here, we investigate the potential of laser-induced vapour nanobubbles (VNBs) formed around plasmonic nanoparticles to locally disturb biofilm integrity and improve antibiotics diffusion. Our results show that biofilms of both Gram-negative (Burkholderia multivorans, Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria can be loaded with cationic 70-nm gold nanoparticles and that subsequent laser illumination results in VNB formation inside the biofilms. In all types of biofilms tested, VNB formation leads to substantial local biofilm disruption, increasing tobramycin efficacy up to 1-3 orders of magnitude depending on the organism and treatment conditions. Altogether, our results support the potential of laser-induced VNBs as a new approach to disrupt biofilms of a broad range of organisms, resulting in improved antibiotic diffusion and more effective biofilm eradication.
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Affiliation(s)
- Eline Teirlinck
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
| | - Ranhua Xiong
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
| | - Toon Brans
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
| | - Katrien Forier
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
- Laboratory of Toxicology, Ghent University Hospital, Ghent, 9000, Belgium
| | - Juan Fraire
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
| | - Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, University of Ghent, Ghent, 9000, Belgium
| | - Nele Matthijs
- Laboratory of Pharmaceutical Microbiology, University of Ghent, Ghent, 9000, Belgium
| | - Riet De Rycke
- Department of Biomedical Molecular Biology, VIB Center for Inflammation Research, Ghent University, 9052, Ghent, Belgium
- Expertise Centre for Transmission Electron Microscopy, VIB BioImaging Core, Ghent University, Ghent, 9052, Belgium
| | - Stefaan C De Smedt
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, University of Ghent, Ghent, 9000, Belgium
| | - Kevin Braeckmans
- Laboratory of General Biochemistry and Physical Pharmacy, University of Ghent, Ghent, 9000, Belgium.
- Centre for Nano- and Biophotonics, Ghent, 9000, Belgium.
- IEMN UMR 8520, Université de Lille, Villeneuve d'Ascq, 59652, France.
- Laboratoire de Physique des Lasers, Atomes et Molécules UMR 8523, Villeneuve d'Ascq, 59655, France.
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80
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Towards standardized mechanical characterization of microbial biofilms: analysis and critical review. NPJ Biofilms Microbiomes 2018; 4:17. [PMID: 30131867 PMCID: PMC6102240 DOI: 10.1038/s41522-018-0062-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 02/05/2023] Open
Abstract
Developing reliable anti-biofilm strategies or efficient biofilm-based bioprocesses strongly depends on having a clear understanding of the mechanisms underlying biofilm development, and knowledge of the relevant mechanical parameters describing microbial biofilm behavior. Many varied mechanical testing methods are available to assess these parameters. The mechanical properties thus identified can then be used to compare protocols such as antibiotic screening. However, the lack of standardization in both mechanical testing and the associated identification methods for a given microbiological goal remains a blind spot in the biofilm community. The pursuit of standardization is problematic, as biofilms are living structures, i.e., both complex and dynamic. Here, we review the main available methods for characterizing the mechanical properties of biofilms through the lens of the relationship linking experimental testing to the identification of mechanical parameters. We propose guidelines for characterizing biofilms according to microbiological objectives that will help the reader choose an appropriate test and a relevant identification method for measuring any given mechanical parameter. The use of a common methodology for the mechanical characterization of biofilms will enable reliable analysis and comparison of microbiological protocols needed for improvement of engineering process and screening.
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81
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Rodrigues JBDS, Souza NTD, Scarano JOA, Sousa JMD, Lira MC, Figueiredo RCBQD, de Souza EL, Magnani M. Efficacy of using oregano essential oil and carvacrol to remove young and mature Staphylococcus aureus biofilms on food-contact surfaces of stainless steel. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.03.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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82
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Conrad JC, Poling-Skutvik R. Confined Flow: Consequences and Implications for Bacteria and Biofilms. Annu Rev Chem Biomol Eng 2018; 9:175-200. [DOI: 10.1146/annurev-chembioeng-060817-084006] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacteria overwhelmingly live in geometrically confined habitats that feature small pores or cavities, narrow channels, or nearby interfaces. Fluid flows through these confined habitats are ubiquitous in both natural and artificial environments colonized by bacteria. Moreover, these flows occur on time and length scales comparable to those associated with motility of bacteria and with the formation and growth of biofilms, which are surface-associated communities that house the vast majority of bacteria to protect them from host and environmental stresses. This review describes the emerging understanding of how flow near surfaces and within channels and pores alters physical processes that control how bacteria disperse, attach to surfaces, and form biofilms. This understanding will inform the development and deployment of technologies for drug delivery, water treatment, and antifouling coatings and guide the structuring of bacterial consortia for production of chemicals and pharmaceuticals.
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Affiliation(s)
- Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA
| | - Ryan Poling-Skutvik
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA
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83
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Theoretical Insight into the Biodegradation of Solitary Oil Microdroplets Moving through a Water Column. Bioengineering (Basel) 2018; 5:bioengineering5010015. [PMID: 29439555 PMCID: PMC5874881 DOI: 10.3390/bioengineering5010015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/05/2018] [Accepted: 02/09/2018] [Indexed: 11/30/2022] Open
Abstract
In the aftermath of oil spills in the sea, clouds of droplets drift into the seawater column and are carried away by sea currents. The fate of the drifting droplets is determined by natural attenuation processes, mainly dissolution into the seawater and biodegradation by oil-degrading microbial communities. Specifically, microbes have developed three fundamental strategies for accessing and assimilating oily substrates. Depending on their affinity for the oily phase and ability to proliferate in multicellular structures, microbes might either attach to the oil surface and directly uptake compounds from the oily phase, or grow suspended in the aqueous phase consuming solubilized oil, or form three-dimensional biofilms over the oil–water interface. In this work, a compound particle model that accounts for all three microbial strategies is developed for the biodegradation of solitary oil microdroplets moving through a water column. Under a set of educated hypotheses, the hydrodynamics and solute transport problems are amenable to analytical solutions and a closed-form correlation is established for the overall dissolution rate as a function of the Thiele modulus, the Biot number and other key parameters. Moreover, two coupled ordinary differential equations are formulated for the evolution of the particle size and used to investigate the impact of the dissolution and biodegradation processes on the droplet shrinking rate.
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84
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Zhang E, Yu Q, Zhai W, Wang F, Scott K. High tolerance of and removal of cefazolin sodium in single-chamber microbial fuel cells operation. BIORESOURCE TECHNOLOGY 2018; 249:76-81. [PMID: 29040863 DOI: 10.1016/j.biortech.2017.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/28/2017] [Accepted: 10/01/2017] [Indexed: 06/07/2023]
Abstract
Single-chamber microbial fuel cells (MFCs) have been shown to be a promising approach for cefazolin sodium (CFZS)-contaminated wastewater treatment, in terms of electricity production, high CFZS tolerance and effective CFZS removal. MFCs exposed to CFZS loadings up to 100 mg L-1, produced stable power of 18.2 ± 1.1 W m-3 and a maximum power of 30.4 ± 2.1 W m-3, similar to that of CFZS-free MFCs (stable power 19.4 ± 0.8 W m-3 and maximum power 32.5 ± 1.6 W m-3), notwithstanding a longer acclimitisation MFC activation. More anodophilic genera (i.e. Acinetobacter, Stenotrophomonas, Lysinibacillus) and antibiotic-resisting genera (i.e. Dysgonomonas) were enriched in CFZS acclimitised anodes. Both the thickness of biofilms and the duration of CFZS acclimitisation were essential for the development of high CFZS tolerance (e.g. 450 mg L-1). The inhibition of MFCs by CFZS was reversible. The present MFCs generated a CFZS removal rate of 1.2-6.8 mg L-1 h-1 without any apparent inhibition of electricity production.
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Affiliation(s)
- Enren Zhang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City 225002, China.
| | - Qingling Yu
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City 225002, China
| | - Wenjing Zhai
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City 225002, China
| | - Feng Wang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City 225002, China
| | - Keith Scott
- School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle NE1 7RU, United Kingdom
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85
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Ma TM, VanEpps JS, Solomon MJ. Structure, Mechanics, and Instability of Fibrin Clot Infected with Staphylococcus epidermidis. Biophys J 2017; 113:2100-2109. [PMID: 29117532 DOI: 10.1016/j.bpj.2017.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 07/20/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022] Open
Abstract
Health care-associated infection, over half of which can be attributed to indwelling medical devices, is a strong risk factor for thromboembolism. Although most experimental models of medical device infection draw upon isolated bacterial biofilms, in fact there is no infection without host protein contribution. Here we study, to our knowledge, a new model for medical device infection-that of an infected fibrin clot-and show that the common blood-borne pathogen Staphylococcus epidermidis influences this in vitro model of a blood clot mechanically and structurally on both microscopic and macroscopic scales. Bacteria present during clot formation produce a visibly disorganized microstructure that increases clot stiffness and triggers mechanical instability over time. Our results provide insight into the observed correlation between medical device infection and thromboembolism; the increase in model clot heterogeneity shows that S. epidermidis can rupture a fibrin clot. The resultant embolization of the infected clot can contribute to the systemic dissemination of the pathogen.
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Affiliation(s)
- Tianhui Maria Ma
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan
| | - J Scott VanEpps
- Department of Emergency Medicine, Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan.
| | - Michael J Solomon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan.
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86
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Inhibiting P. fluorescens biofilms with fluoropolymer-embedded silver nanoparticles: an in-situ spectroscopic study. Sci Rep 2017; 7:11870. [PMID: 28928400 PMCID: PMC5605679 DOI: 10.1038/s41598-017-12088-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 09/04/2017] [Indexed: 11/08/2022] Open
Abstract
Surface colonization by microorganisms leads to the formation of biofilms, i.e. aggregates of bacteria embedded within a matrix of extracellular polymeric substance. This promotes adhesion to the surface and protects bacterial community, providing an antimicrobial-resistant environment. The inhibition of biofilm growth is a crucial issue for preventing bacterial infections. Inorganic nanoparticle/Teflon-like (CFx) composites deposited via ion beam sputtering demonstrated very efficient antimicrobial activity. In this study, we developed Ag-CFx thin films with tuneable metal loadings and exceptional in-plane morphological and chemical homogeneity. Ag-CFx antimicrobial activity was studied via mid-infrared attenuated total reflection spectroscopy utilizing specifically adapted multi-reflection waveguides. Biofilm was sampled by carefully depositing the Ag-CFx film on IR inactive regions of the waveguide. Real-time infrared spectroscopy was used to monitor Pseudomonas fluorescens biofilm growth inhibition induced by the bioactive silver ions released from the nanoantimicrobial coating. Few hours of Ag-CFx action were sufficient to affect significantly biofilm growth. These findings were corroborated by atomic force microscopy (AFM) studies on living bacteria exposed to the same nanoantimicrobial. Morphological analyses showed a severe bacterial stress, leading to membrane leakage/collapse or to extended cell lysis as a function of incubation time.
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87
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Fabbri S, Li J, Howlin RP, Rmaile A, Gottenbos B, De Jager M, Starke EM, Aspiras M, Ward MT, Cogan NG, Stoodley P. Fluid-driven interfacial instabilities and turbulence in bacterial biofilms. Environ Microbiol 2017; 19:4417-4431. [PMID: 28799690 DOI: 10.1111/1462-2920.13883] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 08/03/2017] [Indexed: 11/27/2022]
Abstract
Biofilms are thin layers of bacteria embedded within a slime matrix that live on surfaces. They are ubiquitous in nature and responsible for many medical and dental infections, industrial fouling and are also evident in ancient fossils. A biofilm structure is shaped by growth, detachment and response to mechanical forces acting on them. The main contribution to biofilm versatility in response to physical forces is the matrix that provides a platform for the bacteria to grow. The interaction between biofilm structure and hydrodynamics remains a fundamental question concerning biofilm dynamics. Here, we document the appearance of ripples and wrinkles in biofilms grown from three species of bacteria when subjected to high-velocity fluid flows. Linear stability analysis suggested that the ripples were Kelvin-Helmholtz Instabilities. The analysis also predicted a strong dependence of the instability formation on biofilm viscosity explaining the different surface corrugations observed. Turbulence through Kelvin-Helmholtz instabilities occurring at the interface demonstrated that the biofilm flows like a viscous liquid under high flow velocities applied within milliseconds. Biofilm fluid-like behavior may have important implications for our understanding of how fluid flow influences biofilm biology since turbulence will likely disrupt metabolite and signal gradients as well as community stratification.
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Affiliation(s)
- Stefania Fabbri
- National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering Department, University of Southampton, Southampton SO17 1BJ, UK
| | - Jian Li
- Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
| | - Robert P Howlin
- National Institute for Health Research Southampton Respiratory Biomedical Research Unit, Southampton Centre for Biomedical Research, University Hospital Southampton NHS Foundation Trust, Southampton SO17 1BJ, UK.,Centre for Biological Sciences, Faculty of Natural and Environmental Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Amir Rmaile
- Philips Research, Eindhoven 5656, AE, The Netherlands
| | | | | | | | | | | | - Nicholas G Cogan
- Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
| | - Paul Stoodley
- National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering Department, University of Southampton, Southampton SO17 1BJ, UK.,Department of Microbial Infection and Immunity and the Department of Orthopaedics, Centre for Microbial Interface Biology, The Ohio State University, Columbus, OH, 43210, USA
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88
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Karampatzakis A, Song CZ, Allsopp LP, Filloux A, Rice SA, Cohen Y, Wohland T, Török P. Probing the internal micromechanical properties of Pseudomonas aeruginosa biofilms by Brillouin imaging. NPJ Biofilms Microbiomes 2017; 3:20. [PMID: 28900539 PMCID: PMC5591272 DOI: 10.1038/s41522-017-0028-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 12/17/2022] Open
Abstract
Biofilms are organised aggregates of bacteria that adhere to each other or surfaces. The matrix of extracellular polymeric substances that holds the cells together provides the mechanical stability of the biofilm. In this study, we have applied Brillouin microscopy, a technique that is capable of measuring mechanical properties of specimens on a micrometre scale based on the shift in frequency of light incident upon a sample due to thermal fluctuations, to investigate the micromechanical properties of an active, live Pseudomonas aeruginosa biofilm. Using this non-contact and label-free technique, we have extracted information about the internal stiffness of biofilms under continuous flow. No correlation with colony size was found when comparing the averages of Brillouin shifts of two-dimensional cross-sections of randomly selected colonies. However, when focusing on single colonies, we observed two distinct spatial patterns: in smaller colonies, stiffness increased towards their interior, indicating a more compact structure of the centre of the colony, whereas, larger (over 45 μm) colonies were found to have less stiff interiors. A specialized microscopy technique can monitor biofilm stiffness in a non-destructive manner, yielding insights into biofilm structure and development. The technique, called Brillouin imaging, uses changes in the frequency of light interacting with a substance to reveal fine detail about the material’s mechanical properties. Peter Török and colleagues at Imperial College London, with co-workers in Singapore, used Brillouin imaging to study biofilms of Pseudomonas aeruginosa bacteria at different stages in their life cycle. In young colonies, stiffness increased towards the interior of the biofilm, while mature colonies had less stiff interiors. The older biofilms may therefore have hollow interiors or may have been moving towards a phase of bacterial dispersal from the biofilm state. This non-disruptive method to study mechanical variations within and between living biofilms may help efforts to combat biofilms in clinical, environmental and industrial situations.
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Affiliation(s)
- A Karampatzakis
- Centre for BioImaging Sciences, National University of Singapore, Singapore, 117557 Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 117557 Singapore.,Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
| | - C Z Song
- Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
| | - L P Allsopp
- Imperial College London, Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, South Kensington Campus, Flowers Building, SW7 2AZ London, United Kingdom
| | - A Filloux
- Imperial College London, Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, South Kensington Campus, Flowers Building, SW7 2AZ London, United Kingdom
| | - S A Rice
- Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University Singapore, Singapore, 637551 Singapore
| | - Y Cohen
- Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University Singapore, Singapore, 637551 Singapore
| | - T Wohland
- Centre for BioImaging Sciences, National University of Singapore, Singapore, 117557 Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 117557 Singapore.,Department of Biological Sciences and Department of Chemistry, National University of Singapore, Singapore, 117346 Singapore
| | - P Török
- Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
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89
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Herrling MP, Weisbrodt J, Kirkland CM, Williamson NH, Lackner S, Codd SL, Seymour JD, Guthausen G, Horn H. NMR investigation of water diffusion in different biofilm structures. Biotechnol Bioeng 2017; 114:2857-2867. [PMID: 28755486 DOI: 10.1002/bit.26392] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/08/2017] [Accepted: 07/23/2017] [Indexed: 01/19/2023]
Abstract
Mass transfer in biofilms is determined by diffusion. Different mostly invasive approaches have been used to measure diffusion coefficients in biofilms, however, data on heterogeneous biomass under realistic conditions is still missing. To non-invasively elucidate fluid-structure interactions in complex multispecies biofilms pulsed field gradient-nuclear magnetic resonance (PFG-NMR) was applied to measure the water diffusion in five different types of biomass aggregates: one type of sludge flocs, two types of biofilm, and two types of granules. Data analysis is an important issue when measuring heterogeneous systems and is shown to significantly influence the interpretation and understanding of water diffusion. With respect to numerical reproducibility and physico-chemical interpretation, different data processing methods were explored: (bi)-exponential data analysis and the Γ distribution model. Furthermore, the diffusion coefficient distribution in relation to relaxation was studied by D-T2 maps obtained by 2D inverse Laplace transform (2D ILT). The results show that the effective diffusion coefficients for all biofilm samples ranged from 0.36 to 0.96 relative to that of water. NMR diffusion was linked to biofilm structure (e.g., biomass density, organic and inorganic matter) as observed by magnetic resonance imaging and to traditional biofilm parameters: diffusion was most restricted in granules with compact structures, and fast diffusion was found in heterotrophic biofilms with fluffy structures. The effective diffusion coefficients in the biomass were found to be broadly distributed because of internal biomass heterogeneities, such as gas bubbles, precipitates, and locally changing biofilm densities. Thus, estimations based on biofilm bulk properties in multispecies systems can be overestimated and mean diffusion coefficients might not be sufficiently informative to describe mass transport in biofilms and the near bulk.
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Affiliation(s)
- Maria P Herrling
- Department of Wastewater Engineering, Institute IWAR, Technische Universität Darmstadt, Darmstadt, Germany.,Department of Water Chemistry and Water Technology, Engler-Bunte-Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jessica Weisbrodt
- Department of Water Chemistry and Water Technology, Engler-Bunte-Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Catherine M Kirkland
- Center of Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, Montana
| | - Nathan H Williamson
- Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide, Australia
| | - Susanne Lackner
- Department of Wastewater Engineering, Institute IWAR, Technische Universität Darmstadt, Darmstadt, Germany
| | - Sarah L Codd
- Center of Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, Montana
| | - Joseph D Seymour
- Center of Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
| | - Gisela Guthausen
- Department of Water Chemistry and Water Technology, Engler-Bunte-Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute of Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Harald Horn
- Department of Water Chemistry and Water Technology, Engler-Bunte-Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
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90
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Tecon R, Or D. Biophysical processes supporting the diversity of microbial life in soil. FEMS Microbiol Rev 2017; 41:599-623. [PMID: 28961933 PMCID: PMC5812502 DOI: 10.1093/femsre/fux039] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/10/2017] [Indexed: 12/13/2022] Open
Abstract
Soil, the living terrestrial skin of the Earth, plays a central role in supporting life and is home to an unimaginable diversity of microorganisms. This review explores key drivers for microbial life in soils under different climates and land-use practices at scales ranging from soil pores to landscapes. We delineate special features of soil as a microbial habitat (focusing on bacteria) and the consequences for microbial communities. This review covers recent modeling advances that link soil physical processes with microbial life (termed biophysical processes). Readers are introduced to concepts governing water organization in soil pores and associated transport properties and microbial dispersion ranges often determined by the spatial organization of a highly dynamic soil aqueous phase. The narrow hydrological windows of wetting and aqueous phase connectedness are crucial for resource distribution and longer range transport of microorganisms. Feedbacks between microbial activity and their immediate environment are responsible for emergence and stabilization of soil structure-the scaffolding for soil ecological functioning. We synthesize insights from historical and contemporary studies to provide an outlook for the challenges and opportunities for developing a quantitative ecological framework to delineate and predict the microbial component of soil functioning.
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Affiliation(s)
- Robin Tecon
- Soil and Terrestrial Environmental Physics, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Dani Or
- Soil and Terrestrial Environmental Physics, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland
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91
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Extracellular-matrix-mediated osmotic pressure drives Vibrio cholerae biofilm expansion and cheater exclusion. Nat Commun 2017; 8:327. [PMID: 28835649 PMCID: PMC5569112 DOI: 10.1038/s41467-017-00401-1] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 06/26/2017] [Indexed: 01/23/2023] Open
Abstract
Biofilms, surface-attached communities of bacteria encased in an extracellular matrix, are a major mode of bacterial life. How the material properties of the matrix contribute to biofilm growth and robustness is largely unexplored, in particular in response to environmental perturbations such as changes in osmotic pressure. Here, using Vibrio cholerae as our model organism, we show that during active cell growth, matrix production enables biofilm-dwelling bacterial cells to establish an osmotic pressure difference between the biofilm and the external environment. This pressure difference promotes biofilm expansion on nutritious surfaces by physically swelling the colony, which enhances nutrient uptake, and enables matrix-producing cells to outcompete non-matrix-producing cheaters via physical exclusion. Osmotic pressure together with crosslinking of the matrix also controls the growth of submerged biofilms and their susceptibility to invasion by planktonic cells. As the basic physicochemical principles of matrix crosslinking and osmotic swelling are universal, our findings may have implications for other biofilm-forming bacterial species.Most bacteria live in biofilms, surface-attached communities encased in an extracellular matrix. Here, Yan et al. show that matrix production in Vibrio cholerae increases the osmotic pressure within the biofilm, promoting biofilm expansion and physical exclusion of non-matrix producing cheaters.
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92
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Ebersole JL, Dawson D, Emecen-Huja P, Nagarajan R, Howard K, Grady ME, Thompson K, Peyyala R, Al-Attar A, Lethbridge K, Kirakodu S, Gonzalez OA. The periodontal war: microbes and immunity. Periodontol 2000 2017; 75:52-115. [DOI: 10.1111/prd.12222] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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93
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Continuum and discrete approach in modeling biofilm development and structure: a review. J Math Biol 2017; 76:945-1003. [PMID: 28741178 DOI: 10.1007/s00285-017-1165-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/04/2017] [Indexed: 12/21/2022]
Abstract
The scientific community has recognized that almost 99% of the microbial life on earth is represented by biofilms. Considering the impacts of their sessile lifestyle on both natural and human activities, extensive experimental activity has been carried out to understand how biofilms grow and interact with the environment. Many mathematical models have also been developed to simulate and elucidate the main processes characterizing the biofilm growth. Two main mathematical approaches for biomass representation can be distinguished: continuum and discrete. This review is aimed at exploring the main characteristics of each approach. Continuum models can simulate the biofilm processes in a quantitative and deterministic way. However, they require a multidimensional formulation to take into account the biofilm spatial heterogeneity, which makes the models quite complicated, requiring significant computational effort. Discrete models are more recent and can represent the typical multidimensional structural heterogeneity of biofilm reflecting the experimental expectations, but they generate computational results including elements of randomness and introduce stochastic effects into the solutions.
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94
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Kundukad B, Schussman M, Yang K, Seviour T, Yang L, Rice SA, Kjelleberg S, Doyle PS. Mechanistic action of weak acid drugs on biofilms. Sci Rep 2017; 7:4783. [PMID: 28684849 PMCID: PMC5500524 DOI: 10.1038/s41598-017-05178-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/24/2017] [Indexed: 01/18/2023] Open
Abstract
Selective permeability of a biofilm matrix to some drugs has resulted in the development of drug tolerant bacteria. Here we studied the efficacy of a weak organic acid drug, N-acetyl-L-cysteine (NAC), on the eradication of biofilms formed by the mucoid strain of Pseudomonas aeruginosa and investigated the commonality of this drug with that of acetic acid. We showed that NAC and acetic acid at pH < pKa can penetrate the matrix and eventually kill 100% of the bacteria embedded in the biofilm. Once the bacteria are killed, the microcolonies swell in size and passively shed bacteria, suggesting that the bacteria act as crosslinkers within the extracellular matrix. Despite shedding of the bacteria, the remnant matrix remains intact and behaves as a pH-responsive hydrogel. These studies not only have implications for drug design but also offer a route to generate robust soft matter materials.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore
| | - Megan Schussman
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Kaiyuan Yang
- Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW, Australia
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore.
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
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95
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Witten J, Ribbeck K. The particle in the spider's web: transport through biological hydrogels. NANOSCALE 2017; 9:8080-8095. [PMID: 28580973 PMCID: PMC5841163 DOI: 10.1039/c6nr09736g] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Biological hydrogels such as mucus, extracellular matrix, biofilms, and the nuclear pore have diverse functions and compositions, but all act as selectively permeable barriers to the diffusion of particles. Each barrier has a crosslinked polymeric mesh that blocks penetration of large particles such as pathogens, nanotherapeutics, or macromolecules. These polymeric meshes also employ interactive filtering, in which affinity between solutes and the gel matrix controls permeability. Interactive filtering affects the transport of particles of all sizes including peptides, antibiotics, and nanoparticles and in many cases this filtering can be described in terms of the effects of charge and hydrophobicity. The concepts described in this review can guide strategies to exploit or overcome gel barriers, particularly for applications in diagnostics, pharmacology, biomaterials, and drug delivery.
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Affiliation(s)
- Jacob Witten
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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96
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Flemming HC, Wingender J, Szewzyk U, Steinberg P, Rice SA, Kjelleberg S. Biofilms: an emergent form of bacterial life. Nat Rev Microbiol 2017; 14:563-75. [PMID: 27510863 DOI: 10.1038/nrmicro.2016.94] [Citation(s) in RCA: 2839] [Impact Index Per Article: 405.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bacterial biofilms are formed by communities that are embedded in a self-produced matrix of extracellular polymeric substances (EPS). Importantly, bacteria in biofilms exhibit a set of 'emergent properties' that differ substantially from free-living bacterial cells. In this Review, we consider the fundamental role of the biofilm matrix in establishing the emergent properties of biofilms, describing how the characteristic features of biofilms - such as social cooperation, resource capture and enhanced survival of exposure to antimicrobials - all rely on the structural and functional properties of the matrix. Finally, we highlight the value of an ecological perspective in the study of the emergent properties of biofilms, which enables an appreciation of the ecological success of biofilms as habitat formers and, more generally, as a bacterial lifestyle.
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Affiliation(s)
- Hans-Curt Flemming
- University of Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Universitätsstrasse 5, D-45141 Essen, Germany
| | - Jost Wingender
- University of Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Universitätsstrasse 5, D-45141 Essen, Germany
| | - Ulrich Szewzyk
- Technical University of Berlin, Department of Environmental Microbiology, Ernst-Reuter-Platz 1, D-10587 Berlin, Germany
| | - Peter Steinberg
- The School of Biological, Earth and Environmental Sciences and The Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW 2052, Australia
| | - Scott A Rice
- The Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Staffan Kjelleberg
- The Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University, Singapore 637551
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97
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Walker J, Moore G, Collins S, Parks S, Garvey MI, Lamagni T, Smith G, Dawkin L, Goldenberg S, Chand M. Microbiological problems and biofilms associated with Mycobacterium chimaera in heater-cooler units used for cardiopulmonary bypass. J Hosp Infect 2017; 96:209-220. [PMID: 28532976 DOI: 10.1016/j.jhin.2017.04.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/19/2017] [Indexed: 01/21/2023]
Abstract
The role of heater-cooler units (HCUs) in the transmission of Mycobacterium chimaera during open heart surgery has been recognized since 2013. Subsequent investigations uncovered a remarkable global outbreak reflecting the wide distribution of implicated devices. HCUs are an essential component of cardiopulmonary bypass operations and their withdrawal would severely affect capacity for life-saving cardiac surgery. However, studies have demonstrated that many HCUs are contaminated with a wide range of micro-organisms, including M. chimaera and complex biofilms. Whole genome sequencing of M. chimaera isolates recovered from one manufacturer's HCUs, worldwide, has demonstrated a high level of genetic similarity, for which the most plausible hypothesis is a point source contamination of the devices. Dissemination of bioaerosols through breaches in the HCU water tanks is the most likely route of transmission and airborne bacteria have been shown to have reached the surgical field even with the use of ultraclean theatre ventilation. Controlling the microbiological quality of the water circulating in HCUs and reducing biofilm formation has been a major challenge for many hospitals. However, enhanced decontamination strategies have been recommended by manufacturers, and, although they are not always effective in eradicating M. chimaera from HCUs, UK hospitals have not reported any new cases of M. chimaera infection since implementing these mitigation strategies. Water safety groups in hospitals should be aware that water in medical devices such as HCUs may act as a vector in the transmission of potentially fatal water-borne infections.
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Affiliation(s)
- J Walker
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton Down, Salisbury, UK.
| | - G Moore
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - S Collins
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - S Parks
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - M I Garvey
- Infection Prevention and Control Team, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, UK
| | - T Lamagni
- Healthcare-Associated Infection & Antimicrobial Resistance Department, National Infection Service, Public Health England, Colindale, London, UK
| | - G Smith
- Public Health England National Mycobacterial Reference Service, Birmingham Public Health Laboratory, Birmingham, UK
| | - L Dawkin
- Estates and Facilities, University Hospitals Coventry and Warwickshire NHS Trust, Walsall, UK
| | - S Goldenberg
- Centre for Clinical Infection and Diagnostics Research, King's College, London and Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - M Chand
- Reference Microbiology, National Infection Service, Public Health England, Colindale, London, UK; Guy's & St Thomas' NHS Foundation Trust, London, UK; National Institute for Health Research, Health Protection Research Unit in Respiratory Infections, Imperial College, London, UK
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98
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Matoz-Fernandez DA, Agoritsas E, Barrat JL, Bertin E, Martens K. Nonlinear Rheology in a Model Biological Tissue. PHYSICAL REVIEW LETTERS 2017; 118:158105. [PMID: 28452505 DOI: 10.1103/physrevlett.118.158105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Indexed: 06/07/2023]
Abstract
The rheological response of dense active matter is a topic of fundamental importance for many processes in nature such as the mechanics of biological tissues. One prominent way to probe mechanical properties of tissues is to study their response to externally applied forces. Using a particle-based model featuring random apoptosis and environment-dependent division rates, we evidence a crossover from linear flow to a shear-thinning regime with an increasing shear rate. To rationalize this nonlinear flow we derive a theoretical mean-field scenario that accounts for the interplay of mechanical and active noise in local stresses. These noises are, respectively, generated by the elastic response of the cell matrix to cell rearrangements and by the internal activity.
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Affiliation(s)
| | - Elisabeth Agoritsas
- Université Grenoble Alpes & CNRS, LIPHY, F-38000 Grenoble, France
- Laboratoire de Physique Théorique, ENS & PSL University, UPMC & Sorbonne Universités, F- 75005 Paris, France
| | | | - Eric Bertin
- Université Grenoble Alpes & CNRS, LIPHY, F-38000 Grenoble, France
| | - Kirsten Martens
- Université Grenoble Alpes & CNRS, LIPHY, F-38000 Grenoble, France
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99
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Wagner M, Horn H. Optical coherence tomography in biofilm research: A comprehensive review. Biotechnol Bioeng 2017; 114:1386-1402. [DOI: 10.1002/bit.26283] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/10/2017] [Accepted: 03/01/2017] [Indexed: 01/29/2023]
Affiliation(s)
- Michael Wagner
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
- Karlsruhe Institute of Technology; Institute of Functional Interfaces; Eggenstein-Leopoldshafen Germany
| | - Harald Horn
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
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100
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Zarabadi MP, Paquet-Mercier F, Charette SJ, Greener J. Hydrodynamic Effects on Biofilms at the Biointerface Using a Microfluidic Electrochemical Cell: Case Study of Pseudomonas sp. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2041-2049. [PMID: 28147485 DOI: 10.1021/acs.langmuir.6b03889] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The anchoring biofilm layer is expected to exhibit a different response to environmental stresses than for portions in the bulk, due to the protection from other strata and the proximity to the attachment surface. The effect of hydrodynamic stress on surface-adhered biofilm layers was tested using a specially designed microfluidic bio flow cell with an embedded three-electrode detection system. In situ electrochemical impedance spectroscopy (EIS) measurements of biocapacitance and bioresistance of Pseudomonas sp. biofilms were conducted during the growth phase and under different shear flow conditions with verification by other surface sensitive techniques. Distinct, but reversible changes to the amount of biofilm and its structure at the attachment surface were observed during the application of elevated shear stress. In contrast, regular microscopy revealed permanent distortion to the biofilm bulk, in the form of streamers and ripples. Following the application of extreme shear stresses, complete removal of significant portions of biofilm outer layers occurred, but this did not change the measured quantity of biofilm at the electrode attachment surface. The structure of the remaining biofilm, however, appeared to be modified and susceptible to further changes following application of shear stress directly to the unprotected biofilm layers at the attachment surface.
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Affiliation(s)
| | | | - Steve J Charette
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec , Québec City, Québec G1V 4G5, Canada
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