1
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Thayyil MI, Philip L. Sustainable treatment scheme for in-situ remediation of contaminated drains using engineered natural systems. CHEMOSPHERE 2024; 361:142469. [PMID: 38810803 DOI: 10.1016/j.chemosphere.2024.142469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 04/27/2024] [Accepted: 05/26/2024] [Indexed: 05/31/2024]
Abstract
Ensuring water security in resource-constrained, densely populated regions is a significant challenge globally. Due to insufficient treatment infrastructure, untreated sewage discharge into drainage channels is prevalent, especially in developing countries. This leads to the pollution of already dwindling water bodies and threatens future water availability. In this context, in-situ treatment within drains using nature-based systems is an attractive option. This study evaluates microbial bioremediation and phytoremediation as engineered natural solutions for in-stream treatment of municipal wastewater. A three-stage treatment system consisting of anoxic biofilm, aerobic biofilm, and hydroponic floating wetlands was adopted. Each stage was optimized for operational parameters through batch and continuous flow studies. The anoxic biofilm system using autoclaved aerated concrete (AAC) as the attachment media, at an optimized hydraulic retention time (HRT) of 2 h, showed the best performance with respect to COD removal. Comparable COD removal was observed in both externally aerated and non-aerated aerobic biofilm systems with coir fibre at 6 h HRT. However, aerated system outperformed non-aerated system at low HRTs. The hydroponic system with Canna indica effectively removed residual ammonia-N with an HRT of 2 h. The sequential continuous flow studies employing the optimized conditions showed significant removals of COD (86%) and ammonia-N (97.6%). The results highlight that locally available materials having a high specific surface area can be used as biofilm supports for COD removal, and floating wetlands employing indigenous macrophytes can be an ideal choice for in-situ nutrient removal. The Life Cycle Assessment (LCA) showed that the developed system did not have direct significant impacts on freshwater eco-toxicity and eutrophication. The proposed hybrid treatment system can be implemented as modular units without major drainage modifications or energy-intensive operations. The study, therefore, finds potential application in densely populated settlements in low-income countries where systematic sewage treatment options remain inadequate.
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Affiliation(s)
- Mohammed Iqbal Thayyil
- Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India
| | - Ligy Philip
- Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India.
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2
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Rouillard KR, Esther CP, Kissner WJ, Plott LM, Bowman DW, Markovetz MR, Hill DB. Combination treatment to improve mucociliary transport of Pseudomonas aeruginosa biofilms. PLoS One 2024; 19:e0294120. [PMID: 38394229 PMCID: PMC10890754 DOI: 10.1371/journal.pone.0294120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 10/25/2023] [Indexed: 02/25/2024] Open
Abstract
People with muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) often have acute or chronic respiratory infections that are difficult to treat due in part to the accumulation of hyperconcentrated mucus within the airway. Mucus accumulation and obstruction promote chronic inflammation and infection and reduce therapeutic efficacy. Bacterial aggregates in the form of biofilms exhibit increased resistance to mechanical stressors from the immune response (e.g., phagocytosis) and chemical treatments including antibiotics. Herein, combination treatments designed to disrupt the mechanical properties of biofilms and potentiate antibiotic efficacy are investigated against mucus-grown Pseudomonas aeruginosa biofilms and optimized to 1) alter biofilm viscoelastic properties, 2) increase mucociliary transport rates, and 3) reduce bacterial viability. A disulfide bond reducing agent (tris(2-carboxyethyl)phosphine, TCEP), a surfactant (NP40), a biopolymer (hyaluronic acid, HA), a DNA degradation enzyme (DNase), and an antibiotic (tobramycin) are tested in various combinations to maximize biofilm disruption. The viscoelastic properties of biofilms are quantified with particle tracking microrheology and transport rates are quantified in a mucociliary transport device comprised of fully differentiated primary human bronchial epithelial cells. The combination of the NP40 with hyaluronic acid and tobramycin was the most effective at increasing mucociliary transport rates, decreasing the viscoelastic properties of mucus, and reducing bacterial viability. Multimechanistic targeting of biofilm infections may ultimately result in improved clinical outcomes, and the results of this study may be translated into future in vivo infection models.
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Affiliation(s)
- Kaitlyn R. Rouillard
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | | | - William J. Kissner
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Lucas M. Plott
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Dean W. Bowman
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Matthew R. Markovetz
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - David B. Hill
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
- Joint Department of Biomedical Engineering, UNC Chapel Hill, Chapel Hill, NC, United States of America
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3
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Rouillard KR, Esther CP, Kissner WJ, Plott LM, Bowman DW, Markovetz MR, Hill DB. Combination Treatment to Improve Mucociliary Transport of Pseudomonas aeruginosa Biofilms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553173. [PMID: 37645913 PMCID: PMC10461968 DOI: 10.1101/2023.08.14.553173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
People with muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) often have acute or chronic respiratory infections that are difficult to treat due in part to the accumulation of hyperconcentrated mucus within the airway. Mucus accumulation and obstruction promote chronic inflammation and infection and reduce therapeutic efficacy. Bacterial aggregates in the form of biofilms exhibit increased resistance to mechanical stressors from the immune response (e.g., phagocytosis) and chemical treatments including antibiotics. Herein, combination treatments designed to disrupt the mechanical properties of biofilms and potentiate antibiotic efficacy are investigated against mucus-grown Pseudomonas aeruginosa biofilms and optimized to 1) alter biofilm viscoelastic properties, 2) increase mucociliary transport rates, and 3) reduce bacterial viability. A disulfide bond reducing agent (tris(2-carboxyethyl)phosphine, TCEP), a surfactant (NP40), a biopolymer (hyaluronic acid, HA), a DNA degradation enzyme (DNase), and an antibiotic (tobramycin) are tested in various combinations to maximize biofilm disruption. The viscoelastic properties of biofilms are quantified with particle tracking microrheology and transport rates are quantified in a mucociliary transport device comprised of fully differentiated primary human bronchial epithelial cells. The combination of the NP40 with hyaluronic acid and tobramycin was the most effective at increasing mucociliary transport rates, decreasing the viscoelastic properties of mucus, and reducing bacterial viability. Multimechanistic targeting of biofilm infections may ultimately result in improved clinical outcomes, and the results of this study may be translated into future in vivo infection models.
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Affiliation(s)
| | | | | | - Lucas M Plott
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
| | - Dean W Bowman
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
| | | | - David B Hill
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
- Joint Department of Biomedical Engineering, UNC Chapel Hill, NC 27599
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4
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Asp ME, Thanh MTH, Dutta S, Comstock JA, Welch RD, Patteson AE. Mechanobiology as a tool for addressing the genotype-to-phenotype problem in microbiology. BIOPHYSICS REVIEWS 2023; 4:021304. [PMID: 38504926 PMCID: PMC10903382 DOI: 10.1063/5.0142121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/03/2023] [Indexed: 03/21/2024]
Abstract
The central hypothesis of the genotype-phenotype relationship is that the phenotype of a developing organism (i.e., its set of observable attributes) depends on its genome and the environment. However, as we learn more about the genetics and biochemistry of living systems, our understanding does not fully extend to the complex multiscale nature of how cells move, interact, and organize; this gap in understanding is referred to as the genotype-to-phenotype problem. The physics of soft matter sets the background on which living organisms evolved, and the cell environment is a strong determinant of cell phenotype. This inevitably leads to challenges as the full function of many genes, and the diversity of cellular behaviors cannot be assessed without wide screens of environmental conditions. Cellular mechanobiology is an emerging field that provides methodologies to understand how cells integrate chemical and physical environmental stress and signals, and how they are transduced to control cell function. Biofilm forming bacteria represent an attractive model because they are fast growing, genetically malleable and can display sophisticated self-organizing developmental behaviors similar to those found in higher organisms. Here, we propose mechanobiology as a new area of study in prokaryotic systems and describe its potential for unveiling new links between an organism's genome and phenome.
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5
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Sarlet A, Ruffine V, Blank KG, Bidan CM. Influence of Metal Cations on the Viscoelastic Properties of Escherichia coli Biofilms. ACS OMEGA 2023; 8:4667-4676. [PMID: 36777596 PMCID: PMC9910073 DOI: 10.1021/acsomega.2c06438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Biofilms frequently cause complications in various areas of human life, e.g., in medicine and in the food industry. More recently, biofilms are discussed as new types of living materials with tunable mechanical properties. In particular, Escherichia coli produces a matrix composed of amyloid-forming curli and phosphoethanolamine-modified cellulose fibers in response to suboptimal environmental conditions. It is currently unknown how the interaction between these fibers contributes to the overall mechanical properties of the formed biofilms and if extrinsic control parameters can be utilized to manipulate these properties. Using shear rheology, we show that biofilms formed by the E. coli K-12 strain AR3110 stiffen by a factor of 2 when exposed to the trivalent metal cations Al(III) and Fe(III), while no such response is observed for the bivalent cations Zn(II) and Ca(II). Strains producing only one matrix component did not show any stiffening response to either cation or even a small softening. No stiffening response was further observed when strains producing only one type of fiber were co-cultured or simply mixed after biofilm growth. These results suggest that the E. coli biofilm matrix is a uniquely structured composite material when both matrix fibers are produced from the same bacterium. While the exact interaction mechanism between curli, phosphoethanolamine-modified cellulose, and trivalent metal cations is currently not known, our results highlight the potential of using extrinsic parameters to understand and control the interplay between biofilm structure and mechanical properties. This will ultimately aid in the development of better strategies for controlling biofilm growth.
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Affiliation(s)
- Adrien Sarlet
- Department
of Biomaterials, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476Potsdam, Germany
| | - Valentin Ruffine
- Mechano(bio)chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476Potsdam, Germany
| | - Kerstin G. Blank
- Mechano(bio)chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476Potsdam, Germany
- Institute
of Experimental Physics, Johannes Kepler
University, Altenberger
Str. 69, 4040Linz, Austria
| | - Cécile M. Bidan
- Department
of Biomaterials, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476Potsdam, Germany
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6
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Li M, Nahum Y, Matouš K, Stoodley P, Nerenberg R. Effects of biofilm heterogeneity on the apparent mechanical properties obtained by shear rheometry. Biotechnol Bioeng 2023; 120:553-561. [PMID: 36305479 DOI: 10.1002/bit.28276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 09/30/2022] [Accepted: 10/24/2022] [Indexed: 01/13/2023]
Abstract
Rheometry is an experimental technique widely used to determine the mechanical properties of biofilms. However, it characterizes the bulk mechanical behavior of the whole biofilm. The effects of biofilm mechanical heterogeneity on rheometry measurements are not known. We used laboratory experiments and computer modeling to explore the effects of biofilm mechanical heterogeneity on the results obtained by rheometry. A synthetic biofilm with layered mechanical properties was studied, and a viscoelastic biofilm theory was employed using the Kelvin-Voigt model. Agar gels with different concentrations were used to prepare the layered, heterogeneous biofilm, which was characterized for mechanical properties in shear mode with a rheometer. Both experiments and simulations indicated that the biofilm properties from rheometry were strongly biased by the weakest portion of the biofilm. The simulation results using linearly stratified mechanical properties from a previous study also showed that the weaker portions of the biofilm dominated the mechanical properties in creep tests. We note that the model can be used as a predictive tool to explore the mechanical behavior of complex biofilm structures beyond those accessible to experiments. Since most biofilms display some degree of mechanical heterogeneity, our results suggest caution should be used in the interpretation of rheometry data. It does not necessarily provide the "average" mechanical properties of the entire biofilm if the mechanical properties are stratified.
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Affiliation(s)
- Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yanina Nahum
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Karel Matouš
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA.,National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering, University of Southampton, Southampton, United Kingdom
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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7
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Flemming HC, van Hullebusch ED, Neu TR, Nielsen PH, Seviour T, Stoodley P, Wingender J, Wuertz S. The biofilm matrix: multitasking in a shared space. Nat Rev Microbiol 2023; 21:70-86. [PMID: 36127518 DOI: 10.1038/s41579-022-00791-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 135.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2022] [Indexed: 01/20/2023]
Abstract
The biofilm matrix can be considered to be a shared space for the encased microbial cells, comprising a wide variety of extracellular polymeric substances (EPS), such as polysaccharides, proteins, amyloids, lipids and extracellular DNA (eDNA), as well as membrane vesicles and humic-like microbially derived refractory substances. EPS are dynamic in space and time and their components interact in complex ways, fulfilling various functions: to stabilize the matrix, acquire nutrients, retain and protect eDNA or exoenzymes, or offer sorption sites for ions and hydrophobic substances. The retention of exoenzymes effectively renders the biofilm matrix an external digestion system influencing the global turnover of biopolymers, considering the ubiquitous relevance of biofilms. Physico-chemical and biological interactions and environmental conditions enable biofilm systems to morph into films, microcolonies and macrocolonies, films, ridges, ripples, columns, pellicles, bubbles, mushrooms and suspended aggregates - in response to the very diverse conditions confronting a particular biofilm community. Assembly and dynamics of the matrix are mostly coordinated by secondary messengers, signalling molecules or small RNAs, in both medically relevant and environmental biofilms. Fully deciphering how bacteria provide structure to the matrix, and thus facilitate and benefit from extracellular reactions, remains the challenge for future biofilm research.
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Affiliation(s)
- Hans-Curt Flemming
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
| | | | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
| | - Per H Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Thomas Seviour
- Aarhus University Centre for Water Technology, Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA.,Department of Orthopaedics, The Ohio State University, Columbus, OH, USA
| | - Jost Wingender
- University of Duisburg-Essen, Biofilm Centre, Department of Aquatic Microbiology, Essen, Germany
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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8
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Rouillard KR, Markovetz MR, Kissner WJ, Boone WL, Plott LM, Hill DB. Altering the viscoelastic properties of mucus-grown Pseudomonas aeruginosa biofilms affects antibiotic susceptibility. Biofilm 2023; 5:100104. [PMID: 36711323 PMCID: PMC9880403 DOI: 10.1016/j.bioflm.2023.100104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/15/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023] Open
Abstract
The viscoelastic properties of biofilms are correlated with their susceptibility to mechanical and chemical stress, and the airway environment in muco-obstructive pulmonary diseases (MOPD) facilitates robust biofilm formation. Hyperconcentrated, viscoelastic mucus promotes chronic inflammation and infection, resulting in increased mucin and DNA concentrations. The viscoelastic properties of biofilms are regulated by biopolymers, including polysaccharides and DNA, and influence responses to antibiotics and phagocytosis. We hypothesize that targeted modulation of biofilm rheology will compromise structural integrity and increase antibiotic susceptibility and mucociliary transport. We evaluate biofilm rheology on the macro, micro, and nano scale as a function of treatment with a reducing agent, a biopolymer, and/or tobramycin to define the relationship between the viscoelastic properties of biofilms and susceptibility. Disruption of the biofilm architecture is associated with altered macroscopic and microscopic moduli, rapid vector permeability, increased antibiotic susceptibility, and improved mucociliary transport, suggesting that biofilm modulating therapeutics will improve the treatment of chronic respiratory infections in MOPD.
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Affiliation(s)
- Kaitlyn R. Rouillard
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Matthew R. Markovetz
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - William J. Kissner
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - William L. Boone
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Lucas M. Plott
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - David B. Hill
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA,Joint Department of Biomedical Engineering, North Carolina State University and the University of North Carolina, Chapel Hill, NC, 27599, USA,Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA,Corresponding author. Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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9
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Geisel S, Secchi E, Vermant J. Experimental challenges in determining the rheological properties of bacterial biofilms. Interface Focus 2022; 12:20220032. [PMID: 36330324 PMCID: PMC9560794 DOI: 10.1098/rsfs.2022.0032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 08/01/2023] Open
Abstract
Bacterial biofilms are communities living in a matrix consisting of self-produced, hydrated extracellular polymeric substances. Most microorganisms adopt the biofilm lifestyle since it protects by conferring resistance to antibiotics and physico-chemical stress factors. Consequently, mechanical removal is often necessary but rendered difficult by the biofilm's complex, viscoelastic response, and adhesive properties. Overall, the mechanical behaviour of biofilms also plays a role in the spreading, dispersal and subsequent colonization of new surfaces. Therefore, the characterization of the mechanical properties of biofilms plays a crucial role in controlling and combating biofilms in industrial and medical environments. We performed in situ shear rheological measurements of Bacillus subtilis biofilms grown between the plates of a rotational rheometer under well-controlled conditions relevant to many biofilm habitats. We investigated how the mechanical history preceding rheological measurements influenced biofilm mechanics and compared these results to the techniques commonly used in the literature. We also compare our results to measurements using interfacial rheology on bacterial pellicles formed at the air-water interface. This work aims to help understand how different growth and measurement conditions contribute to the large variability of mechanical properties reported in the literature and provide a new tool for the rigorous characterization of matrix components and biofilms.
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Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
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10
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Hall-Stoodley L, McCoy KS. Biofilm aggregates and the host airway-microbial interface. Front Cell Infect Microbiol 2022; 12:969326. [PMID: 36081767 PMCID: PMC9445362 DOI: 10.3389/fcimb.2022.969326] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Biofilms are multicellular microbial aggregates that can be associated with host mucosal epithelia in the airway, gut, and genitourinary tract. The host environment plays a critical role in the establishment of these microbial communities in both health and disease. These host mucosal microenvironments however are distinct histologically, functionally, and regarding nutrient availability. This review discusses the specific mucosal epithelial microenvironments lining the airway, focusing on: i) biofilms in the human respiratory tract and the unique airway microenvironments that make it exquisitely suited to defend against infection, and ii) how airway pathophysiology and dysfunctional barrier/clearance mechanisms due to genetic mutations, damage, and inflammation contribute to biofilm infections. The host cellular responses to infection that contribute to resolution or exacerbation, and insights about evaluating and therapeutically targeting airway-associated biofilm infections are briefly discussed. Since so many studies have focused on Pseudomonas aeruginosa in the context of cystic fibrosis (CF) or on Haemophilus influenzae in the context of upper and lower respiratory diseases, these bacteria are used as examples. However, there are notable differences in diseased airway microenvironments and the unique pathophysiology specific to the bacterial pathogens themselves.
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Affiliation(s)
- Luanne Hall-Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, Columbus, OH, United States
- *Correspondence: Luanne Hall-Stoodley,
| | - Karen S. McCoy
- Division of Pulmonary Medicine, Nationwide Children’s Hospital, Columbus, OH, United States
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11
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Deng YH, Ricciardulli T, Won J, Wade MA, Rogers SA, Boppart SA, Flaherty DW, Kong H. Self-locomotive, antimicrobial microrobot (SLAM) swarm for enhanced biofilm elimination. Biomaterials 2022; 287:121610. [PMID: 35696784 PMCID: PMC9763052 DOI: 10.1016/j.biomaterials.2022.121610] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 05/29/2022] [Indexed: 12/20/2022]
Abstract
Biofilm is a major cause of infections and infrastructure deterioration, largely due to molecular diffusion restrictions that hamper the antimicrobial activity of traditional antibiotics and disinfectants. Here, we present a self-locomotive, antimicrobial microrobot (SLAM) swarm that can penetrate, fracture, and detach biofilm and, in turn, nullify bacterial resistance to antibiotics. The SLAM is assembled by loading a controlled mass of manganese oxide nanosheets on diatoms with the polydopamine binder. In hydrogen peroxide solution, SLAMs produce oxygen bubbles that generate thrust to penetrate the rigid and dense Pseudomonas aeruginosa biofilm and self-assemble into a swarm that repeatedly surrounds, expands, and bursts oxygen bubbles. The resulting cavities continue to deform and fracture extracellular polymeric substances from microgrooved silicone substrates and wounded skin explants while decreasing the number of viable bacterial cells. Additionally, SLAM allows irrigating water or antibiotics to access the residual biofilm better, thus enhancing the synergistic efficacy in killing up to 99.9% of bacterial cells.
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Affiliation(s)
- Yu-Heng Deng
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Tomas Ricciardulli
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Jungeun Won
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Matthew A Wade
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Simon A Rogers
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Stephen A Boppart
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - David W Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Hyunjoon Kong
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seongbuk-gu, Seoul, 02841, South Korea.
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12
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Geisel S, Secchi E, Vermant J. The role of surface adhesion on the macroscopic wrinkling of biofilms. eLife 2022; 11:76027. [PMID: 35723588 PMCID: PMC9208754 DOI: 10.7554/elife.76027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies' viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates' surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film’s adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the effective volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.
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Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
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13
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Antioxidants of Fruit Extracts as Antimicrobial Agents against Pathogenic Bacteria. Antioxidants (Basel) 2022; 11:antiox11030602. [PMID: 35326252 PMCID: PMC8945554 DOI: 10.3390/antiox11030602] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/13/2022] [Accepted: 03/18/2022] [Indexed: 02/07/2023] Open
Abstract
Fruit is an essential part of the human diet and is of great interest because of its richness in phytochemicals. Various fruit extracts from citrus, berries and pomegranates have been shown to possess a broad spectrum of medicinal properties. Fruit phytochemicals are of considerable interest because of their antioxidant properties involving different mechanisms of action, which can act against different pathogenic bacteria. The antioxidant capacity of fruit phytochemicals involves different kinds of reactions, such as radical scavenging and chelation or complexation of metal ions. The interaction between fruit phytochemicals and bacteria has different repercussions: it disrupts the cell envelope, disturbs cell–cell communication and gene regulation, and suppresses metabolic and enzymatic activities. Consequently, fruit phytochemicals can directly inhibit bacterial growth or act indirectly by modulating the expression of virulence factors, both of which reduce microbial pathogenicity. The aim of this review was to report our current knowledge on various fruit extracts and their major bioactive compounds, and determine the effectiveness of organic acids, terpenes, polyphenols, and other types of phenolic compounds with antioxidant properties as a source of antimicrobial agents.
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14
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Chauhan R, Kumari S, Goel G, Azmi W. Synergistic combination of malic acid with sodium hypochlorite impairs biofilm of Cronobacter sakazakii. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Nazari M, Bickel S, Benard P, Mason-Jones K, Carminati A, Dippold MA. Biogels in Soils: Plant Mucilage as a Biofilm Matrix That Shapes the Rhizosphere Microbial Habitat. FRONTIERS IN PLANT SCIENCE 2022; 12:798992. [PMID: 35095970 PMCID: PMC8792611 DOI: 10.3389/fpls.2021.798992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Mucilage is a gelatinous high-molecular-weight substance produced by almost all plants, serving numerous functions for plant and soil. To date, research has mainly focused on hydraulic and physical functions of mucilage in the rhizosphere. Studies on the relevance of mucilage as a microbial habitat are scarce. Extracellular polymeric substances (EPS) are similarly gelatinous high-molecular-weight substances produced by microorganisms. EPS support the establishment of microbial assemblages in soils, mainly through providing a moist environment, a protective barrier, and serving as carbon and nutrient sources. We propose that mucilage shares physical and chemical properties with EPS, functioning similarly as a biofilm matrix covering a large extent of the rhizosphere. Our analyses found no evidence of consistent differences in viscosity and surface tension between EPS and mucilage, these being important physical properties. With regard to chemical composition, polysaccharide, protein, neutral monosaccharide, and uronic acid composition also showed no consistent differences between these biogels. Our analyses and literature review suggest that all major functions known for EPS and required for biofilm formation are also provided by mucilage, offering a protected habitat optimized for nutrient mobilization. Mucilage enables high rhizo-microbial abundance and activity by functioning as carbon and nutrient source. We suggest that the role of mucilage as a biofilm matrix has been underestimated, and should be considered in conceptual models of the rhizosphere.
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Affiliation(s)
- Meisam Nazari
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Samuel Bickel
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
| | - Pascal Benard
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
| | - Kyle Mason-Jones
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
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16
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Simões LC, Gomes IB, Sousa H, Borges A, Simões M. Biofilm formation under high shear stress increases resilience to chemical and mechanical challenges. BIOFOULING 2022; 38:1-12. [PMID: 34818957 DOI: 10.1080/08927014.2021.2006189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
The effect that the hydrodynamic conditions under which biofilms are formed has on their persistence is still unknown. This study assessed the behaviour of Pseudomonas fluorescens biofilms, formed on stainless steel under different shear stress (τw) conditions (1, 2 and 4 Pa), to chemical (benzalkonium chloride - BAC, glutaraldehyde - GLUT and sodium hypochlorite - SHC) and mechanical (20 Pa) treatments (alone and combined). The biofilms formed under different τw showed different structural characteristics. Those formed under a higher τw were invariably more tolerant to chemical and mechanical stresses. SHC was the biocide which caused the highest biofilm killing and removal, followed by BAC. The sequential exposure to biocides and mechanical stress was found to be insufficient for effective biofilm control. A basal layer containing biofilm cells mostly in a viable state remained on the surface of the cylinders, particularly for the 2 and 4 Pa-generated biofilms.
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Affiliation(s)
- L C Simões
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - H Sousa
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - A Borges
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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17
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Abstract
Drugs called CFTR modulators improve the physiologic defect underlying cystic fibrosis (CF) and alleviate many disease manifestations. However, studies to date indicate that chronic lung infections that are responsible for most disease-related mortality generally persist. Here, we investigated whether combining the CFTR modulator ivacaftor with an intensive 3.5-month antibiotic course could clear chronic Pseudomonas aeruginosa or Staphylococcus aureus lung infections in subjects with R117H-CFTR, who are highly ivacaftor-responsive. Ivacaftor alone improved CFTR activity, and lung function and inflammation within 48 h, and reduced P. aeruginosa and S. aureus pathogen density by ∼10-fold within a week. Antibiotics produced an additional ∼10-fold reduction in pathogen density, but this reduction was transient in subjects who remained infected. Only 1/5 P. aeruginosa-infected and 1/7 S. aureus-infected subjects became persistently culture-negative after the combined treatment. Subjects appearing to clear infection did not have particularly favorable baseline lung function or inflammation, pathogen density or antibiotic susceptibility, or bronchiectasis scores on CT scans, but they did have remarkably low sweat chloride values before and after ivacaftor. All persistently P. aeruginosa-positive subjects remained infected by their pretreatment strain, whereas subjects persistently S. aureus-positive frequently lost and gained strains. This work suggests chronic CF infections may resist eradication despite marked and rapid modulator-induced improvements in lung infection and inflammation parameters and aggressive antibiotic treatment.
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18
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Duncker KE, Holmes ZA, You L. Engineered microbial consortia: strategies and applications. Microb Cell Fact 2021; 20:211. [PMID: 34784924 PMCID: PMC8597270 DOI: 10.1186/s12934-021-01699-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/23/2021] [Indexed: 11/10/2022] Open
Abstract
Many applications of microbial synthetic biology, such as metabolic engineering and biocomputing, are increasing in design complexity. Implementing complex tasks in single populations can be a challenge because large genetic circuits can be burdensome and difficult to optimize. To overcome these limitations, microbial consortia can be engineered to distribute complex tasks among multiple populations. Recent studies have made substantial progress in programming microbial consortia for both basic understanding and potential applications. Microbial consortia have been designed through diverse strategies, including programming mutualistic interactions, using programmed population control to prevent overgrowth of individual populations, and spatial segregation to reduce competition. Here, we highlight the role of microbial consortia in the advances of metabolic engineering, biofilm production for engineered living materials, biocomputing, and biosensing. Additionally, we discuss the challenges for future research in microbial consortia.
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Affiliation(s)
- Katherine E Duncker
- Department of Biomedical Engineering, Duke University, Durham, NC, 27705, USA
| | - Zachary A Holmes
- Department of Biomedical Engineering, Duke University, Durham, NC, 27705, USA
| | - Lingchong You
- Department of Biomedical Engineering, Duke University, Durham, NC, 27705, USA.
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19
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Rivas DP, Hedgecock ND, Stebe KJ, Leheny RL. Dynamic and mechanical evolution of an oil-water interface during bacterial biofilm formation. SOFT MATTER 2021; 17:8195-8210. [PMID: 34525167 DOI: 10.1039/d1sm00795e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We present an experimental study combining particle tracking, active microrheology, and differential dynamic microscopy (DDM) to investigate the dynamics and rheology of an oil-water interface during biofilm formation by the bacteria Pseudomonas Aeruginosa PA14. The interface transitions from an active fluid dominated by the swimming motion of adsorbed bacteria at early age to an active viscoelastic system at late ages when the biofilm is established. The microrheology measurements using microscale magnetic rods indicate that the biofilm behaves as a viscoelastic solid at late age. The bacteria motility at the interface during the biofilm formation, which is characterized in the DDM measurements, evolves from diffusive motion at early age to constrained, quasi-localized motion at later age. Similarly, the mobility of passively moving colloidal spheres at the interface decreases significantly with increasing interface age and shows a dependence on sphere size after biofilm formation that is orders-of-magnitude larger than that expected in a homogeneous system in equilibrium. We attribute this anomalous size dependence to either length-scale-dependent rheology of the biofilm or widely differing effects of the bacteria activity on the motion of spheres of different sizes.
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Affiliation(s)
- David P Rivas
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA.
| | - Nathan D Hedgecock
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA.
| | - Kathleen J Stebe
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert L Leheny
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA.
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20
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Bakhtiari LA, Wells MJ, Gordon VD. High-throughput assays show the timescale for phagocytic success depends on the target toughness. BIOPHYSICS REVIEWS 2021; 2:031402. [PMID: 34632456 PMCID: PMC8485781 DOI: 10.1063/5.0057071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/07/2021] [Indexed: 11/14/2022]
Abstract
Phagocytic immune cells can clear pathogens from the body by engulfing them. Bacterial biofilms are communities of bacteria that are bound together in a matrix that gives biofilms viscoelastic mechanical properties that do not exist for free-swimming bacteria. Since a neutrophil is too small to engulf an entire biofilm, it must be able to detach and engulf a few bacteria at a time if it is to use phagocytosis to clear the infection. We recently found a negative correlation between the target elasticity and phagocytic success. That earlier work used time-consuming, manual analysis of micrographs of neutrophils and fluorescent beads. Here, we introduce and validate flow cytometry as a fast and high-throughput technique that increases the number of neutrophils analyzed per experiment by two orders of magnitude, while also reducing the time required to do so from hours to minutes. We also introduce the use of polyacrylamide gels in our assay for engulfment success. The tunability of polyacrylamide gels expands the mechanical parameter space we can study, and we find that high toughness and yield strain, even with low elasticity, also impact the phagocytic success as well as the timescale thereof. For stiff gels with low-yield strain, and consequent low toughness, phagocytic success is nearly four times greater when neutrophils are incubated with gels for 6 h than after only 1 h of incubation. In contrast, for soft gels with high-yield strain and consequent high toughness, successful engulfment is much less time-sensitive, increasing by less than a factor of two from 1 to 6 h incubation.
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21
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Sandri A, Haagensen JAJ, Veschetti L, Johansen HK, Molin S, Malerba G, Signoretto C, Boaretti M, Lleo MM. Adaptive Interactions of Achromobacter spp. with Pseudomonas aeruginosa in Cystic Fibrosis Chronic Lung Co-Infection. Pathogens 2021; 10:pathogens10080978. [PMID: 34451442 PMCID: PMC8400197 DOI: 10.3390/pathogens10080978] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/17/2021] [Accepted: 07/26/2021] [Indexed: 12/23/2022] Open
Abstract
In the lungs of patients with cystic fibrosis (CF), the main pathogen Pseudomonas aeruginosa is often co-isolated with other microbes, likely engaging in inter-species interactions. In the case of chronic co-infections, this cohabitation can last for a long time and evolve over time, potentially contributing to the clinical outcome. Interactions involving the emerging pathogens Achromobacter spp. have only rarely been studied, reporting inhibition of P. aeruginosa biofilm formation. To evaluate the possible evolution of such interplay, we assessed the ability of Achromobacter spp. isolates to affect the biofilm formation of co-isolated P. aeruginosa strains during long-term chronic co-infections. We observed both competition and cohabitation. An Achromobacter sp. isolate secreted exoproducts interfering with the adhesion ability of a co-isolated P. aeruginosa strain and affected its biofilm formation. Conversely, a clonal Achromobacter sp. strain later isolated from the same patient, as well as two longitudinal strains from another patient, did not show similar competitive behavior against its P. aeruginosa co-isolates. Genetic variants supporting the higher virulence of the competitive Achromobacter sp. isolate were found in its genome. Our results confirm that both inter-species competition and cohabitation are represented during chronic co-infections in CF airways, and evolution of these interplays can happen even at the late stages of chronic infection.
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Affiliation(s)
- Angela Sandri
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Janus Anders Juul Haagensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; (J.A.J.H.); (S.M.)
| | - Laura Veschetti
- Laboratory of Computational Genomics, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (G.M.)
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark;
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Søren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; (J.A.J.H.); (S.M.)
| | - Giovanni Malerba
- Laboratory of Computational Genomics, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (G.M.)
| | - Caterina Signoretto
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Marzia Boaretti
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Maria M. Lleo
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
- Correspondence: ; Tel.: +39-045-802-7194
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22
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Rahman MU, Fleming DF, Sinha I, Rumbaugh KP, Gordon VD, Christopher GF. Effect of collagen and EPS components on the viscoelasticity of Pseudomonas aeruginosa biofilms. SOFT MATTER 2021; 17:6225-6237. [PMID: 34109345 PMCID: PMC8283923 DOI: 10.1039/d1sm00463h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes thousands of deaths every year in part due to its ability to form biofilms composed of bacteria embedded in a matrix of self-secreted extracellular polysaccharides (EPS), e-DNA, and proteins. In chronic wounds, biofilms are exposed to the host extracellular matrix, of which collagen is a major component. How bacterial EPS interacts with host collagen and whether this interaction affects biofilm viscoelasticity is not well understood. Since physical disruption of biofilms is often used in their removal, knowledge of collagen's effects on biofilm viscoelasticity may enable new treatment strategies that are better tuned to biofilms growing in host environments. In this work, biofilms are grown in the presence of different concentrations of collagen that mimic in vivo conditions. In order to explore collagen's interaction with EPS, nine strains of P. aeruginosa with different patterns of EPS production were used to grow biofilms. Particle tracking microrheology was used to characterize the mechanical development of biofilms over two days. Collagen is found to decrease biofilm compliance and increase relative elasticity regardless of the EPS present in the system. However, this effect is minimized when biofilms overproduce EPS. Collagen appears to become a de facto component of the EPS, through binding to bacteria or physical entanglement.
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Affiliation(s)
- Minhaz Ur Rahman
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
| | - Derek F Fleming
- Department of Surgery, Texas Tech Health Sciences, Lubbock, TX, USA
| | - Indranil Sinha
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
| | | | - Vernita D Gordon
- Department of Physics, Center for Nonlinear Dynamics, Interdisciplinary Life Sciences Graduate Programs, LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX, USA
| | - Gordon F Christopher
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
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23
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Testing of aerosolized ciprofloxacin nanocarriers on cystic fibrosis airway cells infected with P. aeruginosa biofilms. Drug Deliv Transl Res 2021; 11:1752-1765. [PMID: 34047967 PMCID: PMC8236054 DOI: 10.1007/s13346-021-01002-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2021] [Indexed: 01/22/2023]
Abstract
The major pathogen found in the lungs of adult cystic fibrosis (CF) patients is Pseudomonas aeruginosa, which builds antibiotic-resistant biofilms. Pulmonary delivery of antibiotics by inhalation has already been proved advantageous in the clinic, but the development of novel anti-infective aerosol medicines is complex and could benefit from adequate in vitro test systems. This work describes the first in vitro model of human bronchial epithelial cells cultivated at the air-liquid interface (ALI) and infected with P. aeruginosa biofilm and its application to demonstrate the safety and efficacy of aerosolized anti-infective nanocarriers. Such a model may facilitate the translation of novel therapeutic modalities into the clinic, reducing animal experiments and the associated problems of species differences. A preformed biofilm of P. aeruginosa PAO1 was transferred to filter-grown monolayers of the human CF cell line (CFBE41o-) at ALI and additionally supplemented with human tracheobronchial mucus. This experimental protocol provides an appropriate time window to deposit aerosolized ciprofloxacin-loaded nanocarriers at the ALI. When applied 1 h post-infection, the nanocarriers eradicated all planktonic bacteria and reduced the biofilm fraction of the pathogen by log 6, while CFBE41o- viability and barrier properties were maintained. The here described complex in vitro model approach may open new avenues for preclinical safety and efficacy testing of aerosol medicines against P. aeruginosa lung infection.
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24
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Souza-Egipsy V, Vega JF, González-Toril E, Aguilera Á. Biofilm mechanics in an extremely acidic environment: microbiological significance. SOFT MATTER 2021; 17:3672-3680. [PMID: 33683248 DOI: 10.1039/d0sm01975e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A variety of natural biofilms were collected from an extremely acidic environment at Río Tinto (Spain). In order to provide insights into the structure-function relationship, the microstructure of the biofilms was explored using low temperature scanning electron microscopy (LTSEM) in combination with rheological analysis. The creep-recovery experiment results have demonstrated the typical behaviour of viscoelastic materials that combine both elastic and viscous characters. The LTSEM visualization and rheological characterization of biofilms revealed that the network density increased in bacterial biofilms and was the lowest in protist Euglena biofilms. This means that, in the latter biofilms, a lower density of interactions exist, suggesting that the whole system experiences enhanced mobility under external mechanical stress. The samples with the highest dynamic moduli (Leptospirillum-Acidiphilium, Zygnemopsis, Chlorella and Cyanidium) have shown the typical strain thinning behaviour, whereas the Pinnularia and Euglena biofilms exhibited a viscous thickening reaction. The Zygnemopsis filamentous floating structure has the highest cohesive energy and has shown distinctive enhanced resilience and connectivity. This suggests that biofilms should be viewed as soft viscoelastic systems the properties of which are determined by the main organisms and their extracellular polymeric substances. The fractional Maxwell model has been found to explain the rheological behaviour of the observed complex quite well, particularly the power-law behaviour and the characteristic broad relaxation response of these systems.
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Affiliation(s)
- Virginia Souza-Egipsy
- BIOPHYM, Department of Macromolecular Physics, Instituto de Estructura de la Materia (IEM-CSIC), c/Serrano 113 bis, 28006, Madrid, Spain.
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25
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Gloag ES, Wozniak DJ, Stoodley P, Hall-Stoodley L. Mycobacterium abscessus biofilms have viscoelastic properties which may contribute to their recalcitrance in chronic pulmonary infections. Sci Rep 2021; 11:5020. [PMID: 33658597 PMCID: PMC7930093 DOI: 10.1038/s41598-021-84525-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium abscessus is emerging as a cause of recalcitrant chronic pulmonary infections, particularly in people with cystic fibrosis (CF). Biofilm formation has been implicated in the pathology of this organism, however the role of biofilm formation in infection is unclear. Two colony-variants of M. abscessus are routinely isolated from CF samples, smooth (MaSm) and rough (MaRg). These two variants display distinct colony morphologies due to the presence (MaSm) or absence (MaRg) of cell wall glycopeptidolipids (GPLs). We hypothesized that MaSm and MaRg variant biofilms might have different mechanical properties. To test this hypothesis, we performed uniaxial mechanical indentation, and shear rheometry on MaSm and MaRg colony-biofilms. We identified that MaRg biofilms were significantly stiffer than MaSm under a normal force, while MaSm biofilms were more pliant compared to MaRg, under both normal and shear forces. Furthermore, using theoretical indices of mucociliary and cough clearance, we identified that M. abscessus biofilms may be more resistant to mechanical forms of clearance from the lung, compared to another common pulmonary pathogen, Pseudomonas aeruginosa. Thus, the mechanical properties of M. abscessus biofilms may contribute to the persistent nature of pulmonary infections caused by this organism.
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Affiliation(s)
- Erin S Gloag
- Department of Microbial Infection and Immunity, The Ohio State University, 711 Biomedical Research Tower, 460 W 12th Avenue, Columbus, OH, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, 711 Biomedical Research Tower, 460 W 12th Avenue, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, 711 Biomedical Research Tower, 460 W 12th Avenue, Columbus, OH, USA.,Department of Orthopedics, The Ohio State University, Columbus, OH, 43210, USA.,National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, Southampton, SO17 1BJ, UK
| | - Luanne Hall-Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, 711 Biomedical Research Tower, 460 W 12th Avenue, Columbus, OH, USA.
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26
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Pavissich JP, Li M, Nerenberg R. Spatial distribution of mechanical properties in Pseudomonas aeruginosa biofilms, and their potential impacts on biofilm deformation. Biotechnol Bioeng 2021; 118:1564-1575. [PMID: 33415727 DOI: 10.1002/bit.27671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/01/2021] [Accepted: 01/04/2021] [Indexed: 11/08/2022]
Abstract
The mechanical properties of biofilms can be used to predict biofilm deformation under external forces, for example, under fluid flow. We used magnetic tweezers to spatially map the compliance of Pseudomonas aeruginosa biofilms at the microscale, then applied modeling to assess its effects on biofilm deformation. Biofilms were grown in capillary flow cells with Reynolds numbers (Re) ranging from 0.28 to 13.9, bulk dissolved oxygen (DO) concentrations from 1 mg/L to 8 mg/L, and bulk calcium ion (Ca2+ ) concentrations of 0 and 100 mg CaCl2 /L. Higher Re numbers resulted in more uniform biofilm morphologies. The biofilm was stiffer at the center of the flow cell than near the walls. Lower bulk DO led to more stratified biofilms. Higher Ca2+ concentrations led to increased stiffness and more uniform mechanical properties. Using the experimental mechanical properties, fluid-structure interaction models predicted up to 64% greater deformation for heterogeneous biofilms, compared with a homogeneous biofilms with the same average properties. However, the deviation depended on the biofilm morphology and flow regime. Our results show significant spatial mechanical variability exists at the microscale, and that this variability can potentially affect biofilm deformation. The average biofilm mechanical properties, provided in many studies, should be used with caution when predicting biofilm deformation.
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Affiliation(s)
- Juan P Pavissich
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago, Chile.,Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile.,Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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27
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Gloag ES, Fabbri S, Wozniak DJ, Stoodley P. Biofilm mechanics: Implications in infection and survival. Biofilm 2020; 2:100017. [PMID: 33447803 PMCID: PMC7798440 DOI: 10.1016/j.bioflm.2019.100017] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022] Open
Abstract
It has long been recognized that biofilms are viscoelastic materials, however the importance of this attribute to the survival and persistence of these microbial communities is yet to be fully realized. Here we review work, which focuses on understanding biofilm mechanics and put this knowledge in the context of biofilm survival, particularly for biofilm-associated infections. We note that biofilm viscoelasticity may be an evolved property of these communities, and that the production of multiple extracellular polymeric slime components may be a way to ensure the development of biofilms with complex viscoelastic properties. We discuss viscoelasticity facilitating biofilm survival in the context of promoting the formation of larger and stronger biofilms when exposed to shear forces, promoting fluid-like behavior of the biofilm and subsequent biofilm expansion by viscous flow, and enabling resistance to both mechanical and chemical methods of clearance. We conclude that biofilm viscoelasticity contributes to the virulence of chronic biofilm infections.
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Affiliation(s)
- Erin S. Gloag
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
| | | | - Daniel J. Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
- Department of Orthopedics, The Ohio State University, Columbus, OH, 43210, USA
- National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, Southampton, SO17 1BJ, UK
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28
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Joyner K, Yang S, Duncan GA. Microrheology for biomaterial design. APL Bioeng 2020; 4:041508. [PMID: 33415310 PMCID: PMC7775114 DOI: 10.1063/5.0013707] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 11/30/2020] [Indexed: 11/15/2022] Open
Abstract
Microrheology analyzes the microscopic behavior of complex materials by measuring the diffusion and transport of embedded particle probes. This experimental method can provide valuable insight into the design of biomaterials with the ability to connect material properties and biological responses to polymer-scale dynamics and interactions. In this review, we discuss how microrheology can be harnessed as a characterization method complementary to standard techniques in biomaterial design. We begin by introducing the core principles and instruments used to perform microrheology. We then review previous studies that incorporate microrheology in their design process and highlight biomedical applications that have been supported by this approach. Overall, this review provides rationale and practical guidance for the utilization of microrheological analysis to engineer novel biomaterials.
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Affiliation(s)
- Katherine Joyner
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
| | - Sydney Yang
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
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29
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Huang C, Sun PP, Won J, Wang Y, Boppart SA, Nguyen TH. Effect of Nonphosphorus Corrosion Inhibitors on Biofilm Pore Structure and Mechanical Properties. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14716-14724. [PMID: 33124800 PMCID: PMC7949192 DOI: 10.1021/acs.est.0c04645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Understanding the effects of biofilm structural and mechanical properties, which can influence biofilm cohesiveness and detachment under physical stress, is critical for biofilm and biofilm-associated pathogen control. In this study, we used optical coherence tomography (OCT) and nanoindentation to determine the role of silicate and tin (two experimental nonphosphate corrosion inhibitors) on the porous structure and stiffness of three types of multispecies biofilms. These biofilms were grown from groundwater (a drinking water source), and this groundwater was amended with either tin or silicate corrosion inhibitor (0.5 mg/L as Sn and 20 mg/L as SiO2). Based on the elastic moduli of these biofilms, tin biofilms and groundwater biofilms were the stiffest, followed by silicate biofilms. The thickness normalized by the growth time for silicate biofilms was highest at 38 ± 7.1 μm/month, compared to 21 ± 3.2 and 11 ± 2.4 μm/month for tin biofilms and groundwater biofilms, respectively. The silicate biofilms had the greatest overall porosities and were thickest among the three biofilms. Based on the pore network modeling (PNM) of OCT images, larger pores and connections were found in the silicate biofilms compared to those in tin and groundwater biofilms. Our analysis showed that the thicker and more porous biofilms (silicate biofilms) were potentially less resistant to deformation than the thinner and denser biofilms (tin and groundwater biofilms).
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peter P Sun
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jungeun Won
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yin Wang
- Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Stephen A Boppart
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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30
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Kim B, Perez-Calleja P, Li M, Nerenberg R. Effect of predation on the mechanical properties and detachment of MABR biofilms. WATER RESEARCH 2020; 186:116289. [PMID: 32836146 DOI: 10.1016/j.watres.2020.116289] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/30/2020] [Accepted: 08/09/2020] [Indexed: 06/11/2023]
Abstract
The membrane-aerated biofilm reactor (MABR) is an emerging wastewater treatment technology that uses O2-supplying membranes as a biofilm support. Because O2 is supplied from the biofilm base instead of the bulk liquid, MABR biofilms have distinct microbial community structures and behavior. Past research showed that protozoan predation in MABR biofilms can greatly increase biofilm porosity, producing a void layer at the base of the biofilm. We hypothesized that this void layer could weaken the biofilm and promote sloughing, and investigated this with heterotrophic MABR biofilms. A rheometer was used to measure biofilm mechanical strength, and MABR flow cells were used to explore detachment. MABRs supplied with cycloheximide, a protozoan inhibitor, were used as controls. Predation increased the internal void ratio from 6 ± 7% to 50 ± 16%. The storage modulus was 1,780 ± 1,180 Pa with predation condition, compared to 9,800 ± 4,290 Pa for the control. Similarly, the loss modulus was 1,580 ± 729 Pa with predation and 363 ± 189 Pa for the control. When subjected to an increased flow, the biofilm loss was 44 ± 24% for the flow cell with predation, while only 7 ± 9% for the control. This research shows that predation can have an important impact on biofilm porosity in MABRs, reducing the mechanical strength and increasing detachment. Understanding this phenomenon can help develop more effective biofilm control strategies in MABRs.
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Affiliation(s)
- B Kim
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences 156 Fitzpatrick Hall, Notre Dame, IN 46556, USA
| | - P Perez-Calleja
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences 156 Fitzpatrick Hall, Notre Dame, IN 46556, USA.
| | - M Li
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences 156 Fitzpatrick Hall, Notre Dame, IN 46556, USA.
| | - R Nerenberg
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences 156 Fitzpatrick Hall, Notre Dame, IN 46556, USA.
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31
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Ishikawa T, Omori T, Kikuchi K. Bacterial biomechanics-From individual behaviors to biofilm and the gut flora. APL Bioeng 2020; 4:041504. [PMID: 33163845 PMCID: PMC7595747 DOI: 10.1063/5.0026953] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023] Open
Abstract
Bacteria inhabit a variety of locations and play important roles in the environment and health. Our understanding of bacterial biomechanics has improved markedly in the last decade and has revealed that biomechanics play a significant role in microbial biology. The obtained knowledge has enabled investigation of complex phenomena, such as biofilm formation and the dynamics of the gut flora. A bottom-up strategy, i.e., from the cellular to the macroscale, facilitates understanding of macroscopic bacterial phenomena. In this Review, we first cover the biomechanics of individual bacteria in the bulk liquid and on surfaces as the base of complex phenomena. The collective behaviors of bacteria in simple environments are next introduced. We then introduce recent advances in biofilm biomechanics, in which adhesion force and the flow environment play crucial roles. We also review transport phenomena in the intestine and the dynamics of the gut flora, focusing on that in zebrafish. Finally, we provide an overview of the future prospects for the field.
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Affiliation(s)
| | - Toshihiro Omori
- Department Finemechanics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
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32
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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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33
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Kretschmer M, Lieleg O. Chelate chemistry governs ion-specific stiffening of Bacillus subtilis B-1 and Azotobacter vinelandii biofilms. Biomater Sci 2020; 8:1923-1933. [PMID: 32031543 DOI: 10.1039/c9bm01763a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unwanted formation of bacterial biofilms can cause problems in both the medical sector and industrial settings. However, removing them from surfaces remains an ongoing challenge since biofilm bacteria efficiently protect themselves from external influences such as mechanical shear forces by embedding themselves into a matrix of extracellular polymeric substances. Here, we discuss microscopic principles, which are responsible for alterations in the viscoelastic properties of biofilms upon contact with metal ions. We suggest that it is a combination of mainly two parameters, that decides if biofilm stiffening occurs or not: the ion size and the detailed configuration of polyanionic macromolecules from the biofilm matrix. Our results provide new insights in the molecular mechanisms that govern the mechanical properties of biofilms. Also, they indicate that hydrogels comprising purified biopolymers can serve as suitable model systems to reproduce certain aspects of biofilm mechanics - provided that the correct biopolymer is chosen.
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Affiliation(s)
- Martin Kretschmer
- Munich School of Bioengineering and Department of Mechanical Engineering, Technical University of Munich, 85748 Garching, Germany.
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34
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Kovach KN, Fleming D, Wells MJ, Rumbaugh KP, Gordon VD. Specific Disruption of Established Pseudomonas aeruginosa Biofilms Using Polymer-Attacking Enzymes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1585-1595. [PMID: 31990563 PMCID: PMC7063831 DOI: 10.1021/acs.langmuir.9b02188] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Biofilms are communities of bacteria embedded in a polymeric matrix which are found in infections and in environments outside the body. Breaking down the matrix renders biofilms more susceptible to physical disruption and to treatments such as antibiotics. Different species of bacteria, and different strains within the same species, produce different types of matrix polymers. This suggests that targeting specific polymers for disruption may be more effective than nonspecific approaches to disrupting biofilm matrixes. In this study, we treated Pseudomonas aeruginosa biofilms with enzymes that are specific to different matrix polymers. We measured the resulting alteration in biofilm mechanics using bulk rheology and changes in structure using electron microscopy. We find that, for biofilms grown in vitro, the effect of enzymatic treatment is greatest when the enzyme is specific to a dominant matrix polymer. Specifically matched enzymatic treatment tends to reduce yield strain and yield stress and increase the rate of biofilm drying, due to increased diffusivity as a result of network compromise. Electron micrographs qualitatively suggest that well-matched enzymatic treatments reduce long-range structure and shorten connecting network fibers. Previous work has shown that generic glycoside hydrolases can cause dispersal of bacteria from in vivo and ex vivo biofilms into a free-swimming state, and thereby make antibiotic treatment more effective. For biofilms grown in wounded mice, we find that well-matched treatments that result in the greatest mechanical compromise in vitro induce the least dispersal ex vivo. Moreover, we find that generic glycoside hydrolases have no measurable effect on the mechanics of biofilms grown in vitro, while previous work has shown them to be highly effective at inducing dispersal in vivo and ex vivo. This highlights the possibility that effective approaches to eradicating biofilms may depend strongly on the growth environment.
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Affiliation(s)
- Kristin N Kovach
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Derek Fleming
- Department of Surgery , Texas Tech University Health Sciences Center , Lubbock , Texas 79430 , United States
| | - Marilyn J Wells
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Kendra P Rumbaugh
- Department of Surgery , Texas Tech University Health Sciences Center , Lubbock , Texas 79430 , United States
| | - Vernita Diane Gordon
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
- Institute for Cellular and Molecular Biology , The University of Texas at Austin , Austin , Texas 78712 , United States
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35
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Kundukad B, Udayakumar G, Grela E, Kaur D, Rice SA, Kjelleberg S, Doyle PS. Weak acids as an alternative anti-microbial therapy. Biofilm 2020; 2:100019. [PMID: 33447805 PMCID: PMC7798471 DOI: 10.1016/j.bioflm.2020.100019] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/27/2019] [Accepted: 01/06/2020] [Indexed: 12/19/2022] Open
Abstract
Weak acids such as acetic acid and N-acetyl cysteine (NAC) at pH less than their pKa can effectively eradicate biofilms due to their ability to penetrate the biofilm matrix and the cell membrane. However, the optimum conditions for their activity against drug resistant strains, and safety, need to be understood for their application to treat infections or to inactivate biofilms on hard surfaces. Here, we investigate the efficacy and optimum conditions at which weak acids can eradicate biofilms. We compared the efficacy of various mono and triprotic weak acids such as N-acetyl cysteine (NAC), acetic acid, formic acid and citric acid, in eradicating biofilms. We found that monoprotic weak acids/acid drugs can kill mucoid P. aeruginosa mucA biofilm bacteria provided the pH is less than their pKa, demonstrating that the extracellular biofilm matrix does not protect the bacteria from the activity of the weak acids. Triprotic acids, such as citric acid, kill biofilm bacteria at pH < pKa1. However, at a pH between pKa1 and pKa2, citric acid is effective in killing the bacteria at the core of biofilm microcolonies but does not kill the bacteria on the periphery. The efficacy of a monoprotic weak acid (NAC) and triprotic weak acid (citric acid) were tested on biofilms formed by Klebsiella pneumoniae KP1, Pseudomonas putida OUS82, Staphylococcus aureus 15981, P. aeruginosa DK1-NH57388A, a mucoid cystic fibrosis isolate and P. aeruginosa PA_D25, an antibiotic resistant strain. We showed that weak acids have a broad spectrum of activity against a wide range of bacteria, including antibiotic resistant bacteria. Further, we showed that a weak acid drug, NAC, can kill bacteria without being toxic to human cells, if its pH is maintained close to its pKa. Thus weak acids/weak acid drugs target antibiotic resistant bacteria and eradicate the persister cells in biofilms which are tolerant to other conventional methods of biofilm eradication.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore
| | - Gayathri Udayakumar
- School of Life and Physical Sciences, PSB academy, La Trobe University, Australia
| | - Erin Grela
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dhamanpreet Kaur
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore.,The ithree Institute, The University of Technology Sydney, Sydney, NSW, Australia
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore.,Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, 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.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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36
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Falcón García C, Kretschmer M, Lozano-Andrade CN, Schönleitner M, Dragoŝ A, Kovács ÁT, Lieleg O. Metal ions weaken the hydrophobicity and antibiotic resistance of Bacillus subtilis NCIB 3610 biofilms. NPJ Biofilms Microbiomes 2020; 6:1. [PMID: 31908831 PMCID: PMC6941983 DOI: 10.1038/s41522-019-0111-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/03/2019] [Indexed: 02/06/2023] Open
Abstract
Surface superhydrophobicity makes bacterial biofilms very difficult to fight, and it is a combination of their matrix composition and complex surface roughness which synergistically protects these biomaterials from wetting. Although trying to eradicate biofilms with aqueous (antibiotic) solutions is common practice, this can be a futile approach if the biofilms have superhydrophobic properties. To date, there are not many options available to reduce the liquid repellency of biofilms or to prevent this material property from developing. Here, we present a solution to this challenge. We demonstrate how the addition of metal ions such as copper and zinc during or after biofilm formation can render the surface of otherwise superhydrophobic B. subtilis NCIB 3610 biofilms completely wettable. As a result of this procedure, these smoother, hydrophilic biofilms are more susceptible to aqueous antibiotics solutions. Our strategy proposes a scalable and widely applicable step in a multi-faceted approach to eradicate biofilms.
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Affiliation(s)
- Carolina Falcón García
- Department of Mechanical Engineering and Munich School of Bioengineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Martin Kretschmer
- Department of Mechanical Engineering and Munich School of Bioengineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Carlos N. Lozano-Andrade
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800 Kongens Lyngby, Denmark
| | - Markus Schönleitner
- Department of Mechanical Engineering and Munich School of Bioengineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Anna Dragoŝ
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800 Kongens Lyngby, Denmark
| | - Ákos T. Kovács
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800 Kongens Lyngby, Denmark
| | - Oliver Lieleg
- Department of Mechanical Engineering and Munich School of Bioengineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
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37
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Spengler C, Nolle F, Mischo J, Faidt T, Grandthyll S, Thewes N, Koch M, Müller F, Bischoff M, Klatt MA, Jacobs K. Strength of bacterial adhesion on nanostructured surfaces quantified by substrate morphometry. NANOSCALE 2019; 11:19713-19722. [PMID: 31599281 DOI: 10.1039/c9nr04375f] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microbial adhesion and the subsequent formation of resilient biofilms at surfaces are decisively influenced by substrate properties, such as the topography. To date, studies that quantitatively link surface topography and bacterial adhesion are scarce, as both are not straightforward to quantify. To fill this gap, surface morphometry combined with single-cell force spectroscopy was performed on surfaces with irregular topographies on the nano-scale. As surfaces, hydrophobized silicon wafers were used that were etched to exhibit surface structures in the same size range as the bacterial cell wall molecules. The surface structures were characterized by a detailed morphometric analysis based on Minkowski functionals revealing both qualitatively similar features and quantitatively different extensions. We find that as the size of the nanostructures increases, the adhesion forces decrease in a way that can be quantified by the area of the surface that is available for the tethering of cell wall molecules. In addition, we observe a bactericidal effect, which is more pronounced on substrates with taller structures but does not influence adhesion. Our results can be used for a targeted development of 3D-structured materials for/against bio-adhesion. Moreover, the morphometric analysis can serve as a future gold standard for characterizing a broad spectrum of material structures.
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Affiliation(s)
- Christian Spengler
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Friederike Nolle
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Johannes Mischo
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Thomas Faidt
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Samuel Grandthyll
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Nicolas Thewes
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Marcus Koch
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
| | - Frank Müller
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
| | - Markus Bischoff
- Institute of Medical Microbiology and Hygiene, Saarland University, 66421 Homburg/Saar, Germany
| | - Michael Andreas Klatt
- Institute of Stochastics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, Campus E2 9, 66123 Saarbrücken, Germany.
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38
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Assaying How Phagocytic Success Depends on the Elasticity of a Large Target Structure. Biophys J 2019; 117:1496-1507. [PMID: 31586520 DOI: 10.1016/j.bpj.2019.08.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 08/14/2019] [Accepted: 08/26/2019] [Indexed: 01/26/2023] Open
Abstract
Biofilm infections can consist of bacterial aggregates that are an order of magnitude larger than neutrophils, phagocytic immune cells that densely surround aggregates but do not enter them. Because a neutrophil is too small to engulf the entire aggregate, it must be able to detach and engulf a few bacteria at a time if it is to use phagocytosis to clear the infection. Current research techniques do not provide a method for determining how the success of phagocytosis, here defined as the complete engulfment of a piece of foreign material, depends on the mechanical properties of a larger object from which the piece must be removed before being engulfed. This article presents a step toward such a method. By varying polymer concentration or cross-linking density, the elastic moduli of centimeter-sized gels are varied over the range that was previously measured for Pseudomonas aeruginosa biofilms grown from clinical bacterial isolates. Human neutrophils are isolated from blood freshly drawn from healthy adult volunteers, exposed to gel containing embedded beads for 1 h, and removed from the gel. The percentage of collected neutrophils that contain beads that had previously been within the gels is used to measure successful phagocytic engulfment. Both increased polymer concentration in agarose gels and increased cross-linking density in alginate gels are associated with a decreased success of phagocytic engulfment. Upon plotting the percentage of neutrophils showing successful engulfment as a function of the elastic modulus of the gel to which they were applied, it is found that data from both alginate and agarose gels collapse onto the same curve. This suggests that gel mechanics may be impacting the success of phagocytosis and demonstrates that this experiment is a step toward realizing methods for measuring how the mechanics of a large target, or a large structure in which smaller targets are embedded, impact the success of phagocytic engulfment.
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39
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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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40
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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: 20] [Impact Index Per Article: 4.0] [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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Gordon V, Bakhtiari L, Kovach K. From molecules to multispecies ecosystems: the roles of structure in bacterial biofilms. Phys Biol 2019; 16:041001. [PMID: 30913545 DOI: 10.1088/1478-3975/ab1384] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biofilms are communities of sessile microbes that are bound to each other by a matrix made of biopolymers and proteins. Spatial structure is present in biofilms on many lengthscales. These range from the nanometer scale of molecular motifs to the hundred-micron scale of multicellular aggregates. Spatial structure is a physical property that impacts the biology of biofilms in many ways. The molecular structure of matrix components controls their interaction with each other (thereby impacting biofilm mechanics) and with diffusing molecules such as antibiotics and immune factors (thereby impacting antibiotic tolerance and evasion of the immune system). The size and structure of multicellular aggregates, combined with microbial consumption of growth substrate, give rise to differentiated microenvironments with different patterns of metabolism and gene expression. Spatial association of more than one species can benefit one or both species, while distances between species can both determine and result from the transport of diffusible factors between species. Thus, a widespread theme in the biological importance of spatial structure in biofilms is the effect of structure on transport. We survey what is known about this and other effects of spatial structure in biofilms, from molecules up to multispecies ecosystems. We conclude with an overview of what experimental approaches have been developed to control spatial structure in biofilms and how these and other experiments can be complemented with computational work.
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Affiliation(s)
- Vernita Gordon
- Department of Physics, University of Texas at Austin, Austin TX 78712, United States of America. Center for Nonlinear Dynamics, University of Texas at Austin, Austin TX 78712, United States of America. Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin TX 78712, United States of America. Author to whom any correspondence should be addressed
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42
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Liao S, Zhang Y, Pan X, Zhu F, Jiang C, Liu Q, Cheng Z, Dai G, Wu G, Wang L, Chen L. Antibacterial activity and mechanism of silver nanoparticles against multidrug-resistant Pseudomonas aeruginosa. Int J Nanomedicine 2019; 14:1469-1487. [PMID: 30880959 PMCID: PMC6396885 DOI: 10.2147/ijn.s191340] [Citation(s) in RCA: 230] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The threat of drug-resistant Pseudomonas aeruginosa requires great efforts to develop highly effective and safe bactericide. OBJECTIVE This study aimed to investigate the antibacterial activity and mechanism of silver nanoparticles (AgNPs) against multidrug-resistant P. aeruginosa. METHODS The antimicrobial effect of AgNPs on clinical isolates of resistant P. aeruginosa was assessed by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). In multidrug-resistant P. aeruginosa, the alterations of morphology and structure were observed by the transmission electron microscopy (TEM); the differentially expressed proteins were analyzed by quantitative proteomics; the production of reactive oxygen species (ROS) was assayed by H2DCF-DA staining; the activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was chemically measured and the apoptosis-like effect was determined by flow cytometry. RESULTS Antimicrobial tests revealed that AgNPs had highly bactericidal effect on the drug-resistant or multidrug-resistant P. aeruginosa with the MIC range of 1.406-5.625 µg/mL and the MBC range of 2.813-5.625 µg/mL. TEM showed that AgNPs could enter the multidrug-resistant bacteria and impair their morphology and structure. The proteomics quantified that, in the AgNP-treated bacteria, the levels of SOD, CAT, and POD, such as alkyl hydroperoxide reductase and organic hydroperoxide resistance protein, were obviously high, as well as the significant upregulation of low oxygen regulatory oxidases, including cbb3-type cytochrome c oxidase subunit P2, N2, and O2. Further results confirmed the excessive production of ROS. The antioxidants, reduced glutathione and ascorbic acid, partially antagonized the antibacterial action of AgNPs. The apoptosis-like rate of AgNP-treated bacteria was remarkably higher than that of the untreated bacteria (P<0.01). CONCLUSION This study proved that AgNPs could play antimicrobial roles on the multidrug-resistant P. aeruginosa in a concentration- and time-dependent manner. The main mechanism involves the disequilibrium of oxidation and antioxidation processes and the failure to eliminate the excessive ROS.
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Affiliation(s)
- Shijing Liao
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
| | - Yapeng Zhang
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
| | - Xuanhe Pan
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
| | - Feizhou Zhu
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Central South University, Changsha 410013, China
| | - Congyuan Jiang
- Hunan Anson Biotechnology Co., Ltd., Changsha 410008, China
| | - Qianqian Liu
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Central South University, Changsha 410013, China
| | - Zhongyi Cheng
- Jingjie PTM BioLab Co., Ltd., Hangzhou Economic and Technological Development Area, Hangzhou 310018, China
| | - Gan Dai
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
| | - Guojun Wu
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
| | - Linqian Wang
- Department of Clinical Laboratory, Hunan Cancer Hospital, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, China,
| | - Liyu Chen
- Department of Medical Microbiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China,
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43
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Klotz M, Kretschmer M, Goetz A, Ezendam S, Lieleg O, Opitz M. Importance of the biofilm matrix for the erosion stability of Bacillus subtilis NCIB 3610 biofilms. RSC Adv 2019; 9:11521-11529. [PMID: 35520264 PMCID: PMC9063333 DOI: 10.1039/c9ra01955c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/02/2019] [Indexed: 12/12/2022] Open
Abstract
Erosion of bacterial biofilms is dependent on the composition of the biofilm matrix and the surrounding chemical environment.
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Affiliation(s)
- M. Klotz
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
| | - M. Kretschmer
- Munich School of BioEngineering and Department of Mechanical Engineering
- Technische Universität München
- Garching
- Germany
| | - A. Goetz
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
| | - S. Ezendam
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
| | - O. Lieleg
- Munich School of BioEngineering and Department of Mechanical Engineering
- Technische Universität München
- Garching
- Germany
| | - M. Opitz
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
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Falcón García C, Stangl F, Götz A, Zhao W, Sieber SA, Opitz M, Lieleg O. Topographical alterations render bacterial biofilms susceptible to chemical and mechanical stress. Biomater Sci 2019; 7:220-232. [DOI: 10.1039/c8bm00987b] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Treatment with concentrated ethanol, saline or glucose solutions smoothens biofilm surface topography and initially superhydrophobic/omniphobic biofilms are rendered hydrophilic.
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Affiliation(s)
- Carolina Falcón García
- Department of Mechanical Engineering and Munich School of Bioengineering
- Technical University of Munich
- 85748 Garching
- Germany
| | - Felix Stangl
- Department of Mechanical Engineering and Munich School of Bioengineering
- Technical University of Munich
- 85748 Garching
- Germany
| | - Alexandra Götz
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
| | - Weining Zhao
- Department of Chemistry
- Chair for Organic Chemistry II
- Technical University of Munich
- 85748 Garching
- Germany
| | - Stephan A. Sieber
- Department of Chemistry
- Chair for Organic Chemistry II
- Technical University of Munich
- 85748 Garching
- Germany
| | - Madeleine Opitz
- Center for NanoScience
- Faculty of Physics
- Ludwig-Maximilians-Universität München
- Munich
- Germany
| | - Oliver Lieleg
- Department of Mechanical Engineering and Munich School of Bioengineering
- Technical University of Munich
- 85748 Garching
- Germany
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45
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Programmable and printable Bacillus subtilis biofilms as engineered living materials. Nat Chem Biol 2018; 15:34-41. [PMID: 30510190 DOI: 10.1038/s41589-018-0169-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/09/2018] [Indexed: 11/09/2022]
Abstract
Bacterial biofilms can be programmed to produce living materials with self-healing and evolvable functionalities. However, the wider use of artificial biofilms has been hindered by limitations on processability and functional protein secretion capacity. We describe a highly flexible and tunable living functional materials platform based on the TasA amyloid machinery of the bacterium Bacillus subtilis. We demonstrate that genetically programmable TasA fusion proteins harboring diverse functional proteins or domains can be secreted and can assemble into diverse extracellular nano-architectures with tunable physicochemical properties. Our engineered biofilms have the viscoelastic behaviors of hydrogels and can be precisely fabricated into microstructures having a diversity of three-dimensional (3D) shapes using 3D printing and microencapsulation techniques. Notably, these long-lasting and environmentally responsive fabricated living materials remain alive, self-regenerative, and functional. This new tunable platform offers previously unattainable properties for a variety of living functional materials having potential applications in biomaterials, biotechnology, and biomedicine.
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46
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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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Shen Y, Huang PC, Huang C, Sun P, Monroy GL, Wu W, Lin J, Espinosa-Marzal RM, Boppart SA, Liu WT, Nguyen TH. Effect of divalent ions and a polyphosphate on composition, structure, and stiffness of simulated drinking water biofilms. NPJ Biofilms Microbiomes 2018; 4:15. [PMID: 30038792 PMCID: PMC6052100 DOI: 10.1038/s41522-018-0058-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 05/24/2018] [Accepted: 06/01/2018] [Indexed: 02/04/2023] Open
Abstract
The biofilm chemical and physical properties in engineered systems play an important role in governing pathogen transmission, fouling facilities, and corroding metal surfaces. Here, we investigated how simulated drinking water biofilm chemical composition, structure, and stiffness responded to the common scale control practice of adjusting divalent ions and adding polyphosphate. Magnetomotive optical coherence elastography (MM-OCE), a tool developed for diagnosing diseased tissues, was used to determine biofilm stiffness in this study. MM-OCE, together with atomic force microscopy (AFM), revealed that the biofilms developed from a drinking water source with high divalent ions were stiffer compared to biofilms developed either from the drinking water source with low divalent ions or the water containing a scale inhibitor (a polyphosphate). The higher stiffness of biofilms developed from the water containing high divalent ions was attributed to the high content of calcium carbonate, suggested by biofilm composition examination. In addition, by examining the biofilm structure using optical coherence tomography (OCT), the highest biofilm thickness was found for biofilms developed from the water containing the polyphosphate. Compared to the stiff biofilms developed from the water containing high divalent ions, the soft and thick biofilms developed from the water containing polyphosphate will be expected to have higher detachment under drinking water flow. This study suggested that water chemistry could be used to predict the biofilm properties and subsequently design the microbial safety control strategies. A variety of analytical techniques are revealing the complex influences of ions in drinking water supplies on the structure of biofilms. Such biofilms often contaminate water supply pipes and machinery. Yun Shen and colleagues at the University of Illinois at Urbana-Champaign in the USA investigated the effects of ions with a double positive charge – ‘divalent cations’ – and polyphosphate ions. Divalent cations, especially calcium and magnesium ions, are abundant in drinking water in many regions, promoting the formation of limescale deposits. Polyphosphates are commonly added to water supplies to reduce limescale formation, inhibit corrosion and discourage biofilm formation. The research revealed that divalent cations increase biofilm stiffness, while polyphosphates promote softer but thicker biofilms that are more easily removed. The results will help optimize water treatment procedures to control both microbial contamination and limescale problems.
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Affiliation(s)
- Yun Shen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,4Present Address: University of Michigan, 1351 Beal Ave., 219 EWRE Bldg, Ann Arbor, MI 48109-2125 USA
| | - Pin Chieh Huang
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Conghui Huang
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Peng Sun
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Guillermo L Monroy
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wenjing Wu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Jie Lin
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Rosa M Espinosa-Marzal
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Stephen A Boppart
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,3Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wen-Tso Liu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Thanh H Nguyen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
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48
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Larue AE, Swider P, Duru P, Daviaud D, Quintard M, Davit Y. Quantitative 3D comparison of biofilm imaged by X-ray micro-tomography and two-photon laser scanning microscopy. J Microsc 2018; 271:302-314. [PMID: 29926921 DOI: 10.1111/jmi.12718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 05/09/2018] [Indexed: 12/18/2022]
Abstract
Optical imaging techniques for biofilm observation, like laser scanning microscopy, are not applicable when investigating biofilm formation in opaque porous media. X-ray micro-tomography (X-ray CMT) might be an alternative but it finds limitations in similarity of X-ray absorption coefficients for the biofilm and aqueous phases. To overcome this difficulty, barium sulphate was used in Davit et al. (2011) to enable high-resolution 3D imaging of biofilm via X-ray CMT. However, this approach lacks comparison with well-established imaging methods, which are known to capture the fine structures of biofilms, as well as uncertainty quantification. Here, we compare two-photon laser scanning microscopy (TPLSM) images of Pseudomonas Aeruginosa biofilm grown in glass capillaries against X-ray CMT using an improved protocol where barium sulphate is combined with low-gelling temperature agarose to avoid sedimentation. Calibrated phantoms consisting of mono-dispersed fluorescent and X-ray absorbent beads were used to evaluate the uncertainty associated with our protocol along with three different segmentation techniques, namely hysteresis, watershed and region growing, to determine the bias relative to image binarization. Metrics such as volume, 3D surface area and thickness were measured and comparison of both imaging modalities shows that X-ray CMT of biofilm using our protocol yields an accuracy that is comparable and even better in certain respects than TPLSM, even in a nonporous system that is largely favourable to TPLSM.
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Affiliation(s)
- A E Larue
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - P Swider
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - P Duru
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - D Daviaud
- Centre de Physiopathologie de Toulouse Purpan (CPTP) - Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France
| | - M Quintard
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Y Davit
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
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49
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Si T, Ma Z, Tang JX. Capillary flow and mechanical buckling in a growing annular bacterial colony. SOFT MATTER 2018; 14:301-311. [PMID: 29260829 DOI: 10.1039/c7sm01452j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A growing bacterial colony is a dense suspension of an increasing number of cells capable of individual as well as collective motion. After inoculating Pseudomonas aeruginosa over an annular area on an agar plate, we observe the growth and spread of the bacterial population, and model the process by considering the physical effects that account for the features observed. Over a course of 10-12 hours, the majority of bacteria migrate to and accumulate at the edges. We model the capillary flow induced by imbalanced evaporation flux as the cause for the accumulation, much like the well-known coffee stain phenomenon. Simultaneously, periodic buckles or protrusions occur at the inner edge. These buckles indicate that the crowding bacteria produce a jam, transforming the densely packed population at the inner edge to a solid state. The continued bacterial growth produces buckles. Subsequently, a ring of packed bacteria behind the inner edge detach from it and break into pieces, forming bacterial droplets. These droplets slowly coalesce while they continually grow and collectively surf on the agar surface in the region where the colony had previously spread over. Our study shows a clear example of how fluid dynamics and elasto-mechanics together govern the bacterial colony pattern evolution.
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Affiliation(s)
- Tieyan Si
- Harbin Institute of Technology, Harbin, China
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50
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Amrutha B, Sundar K, Shetty PH. Effect of organic acids on biofilm formation and quorum signaling of pathogens from fresh fruits and vegetables. Microb Pathog 2017; 111:156-162. [PMID: 28867627 DOI: 10.1016/j.micpath.2017.08.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 08/23/2017] [Accepted: 08/30/2017] [Indexed: 01/19/2023]
Abstract
Organic acids are known to be used as food preservatives due to their antimicrobial potential. This study evaluated the ability of three organic acids, namely, acetic acid, citric acid and lactic acid to manage E. coli and Salmonella sp. from fresh fruits and vegetables. Effect of these organic acids on biofilm forming ability and anti-quorum potential was also investigated. The effect of organic acids on inactivation of E. coli and Salmonella sp. on the surface of a selected vegetable (cucumber) was determined. The minimum inhibitory concentration of the organic acids were found to be 1.5, 2 and 0.2% in E. coli while it was observed to be 1, 1.5 and 1% in Salmonella sp. for acetic, citric and lactic acids respectively. Maximum inhibition of biofilm formation was recorded at 39.13% with lactic acid in E. coli and a minimum of 22.53% with citric acid in Salmonella sp. EPS production was affected in E. coli with lactic acid showing reduction by 13.42% while citric acid and acetic acid exhibited only 6.25% and 10.89% respectively. Swimming and swarming patterns in E. coli was notably affected by both acetic and lactic acids. Lactic and acetic acids showed higher anti-quorum sensing (QS) potential when compared to citric acid. 2% lactic acid showed a maximum inhibition of violacein production by 37.7%. Organic acids can therefore be used as potential quorum quenching agents in food industry. 2% lactic acid treatment on cucumber demonstrated that it was effective in inactivating E. coli and Salmonella sp. There was 1 log reduction in microbial count over a period of 6 days after the lactic acid treatment. Thus, organic acids can act as effective potential sanitizers in reducing the microbial load associated with fresh fruits and vegetables.
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Affiliation(s)
- Balagopal Amrutha
- Department of Food Science and Technology, Pondicherry Central University, R V Nagar, Kalapet, Puducherry 605 014, India
| | - Kothandapani Sundar
- Department of Food Science and Technology, Pondicherry Central University, R V Nagar, Kalapet, Puducherry 605 014, India
| | - Prathapkumar Halady Shetty
- Department of Food Science and Technology, Pondicherry Central University, R V Nagar, Kalapet, Puducherry 605 014, India.
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