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Yoshida S, Inaba H, Nomura R, Nakano K, Matsumoto-Nakano M. Role of fimbriae variations in Porphyromonas gulae biofilm formation. J Oral Biosci 2024:S1349-0079(24)00193-2. [PMID: 39216533 DOI: 10.1016/j.job.2024.08.003] [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: 05/28/2024] [Revised: 08/09/2024] [Accepted: 08/13/2024] [Indexed: 09/04/2024]
Abstract
OBJECTIVES Porphyromonas gulae is a major causative agent of periodontal disease in companion animals that possesses various virulence factors, including fimbriae, lipopolysaccharides, and proteases. P. gulae fimbriae are classified into three genotypes (A, B, and C) based on their nucleotide sequences. Type C fimbrial isolates have been reported to be more virulent than other fimA types, suggesting that different fimA types may aid in the regulation of periodontal pathogenesis. Detailed findings regarding the ability of P. gulae to form biofilms have yet to be reported. Here, we investigated the contributions of fimbrial genotypes in P. gulae biofilm formation. METHODS P. gulae and P. gingivalis biofilms were generated on plates and analyzed using confocal laser microscopy. Additionally, the biofilms formed were assessed by staining with crystal violet. Furthermore, the physical strength of P. gulae biofilms was examined by ultrasonication. RESULTS Biofilms formed by P. gulae type C were denser than those formed by types A and B. Moreover, the amount of biofilm formed by type C strains was significantly greater than that formed by type A and B strains, which was similar to the biofilms formed by P. gingivalis with type II fimbriae. Additionally, the physical strength of the type C biofilm was significantly greater than that of the other strains. CONCLUSIONS These results suggest that FimA variation may coordinate for biofilm formation. This is the first report on the observation and characterization of P. gulae biofilm formation.
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Affiliation(s)
- Sho Yoshida
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hiroaki Inaba
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Department of Dental Hygiene, Kyoto Koka Women's College, Kyoto, Japan.
| | - Ryota Nomura
- Department of Pediatric Dentistry, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Michiyo Matsumoto-Nakano
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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2
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Pérez-Estay B, Cordero ML, Sepúlveda N, Soto R. Accumulation and depletion of E. coli in surfaces mediated by curvature. Phys Rev E 2024; 109:054601. [PMID: 38907493 DOI: 10.1103/physreve.109.054601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 03/27/2024] [Indexed: 06/24/2024]
Abstract
Can topography be used to control bacteria accumulation? We address this question in the model system of smooth-swimming and run-and-tumble Escherichia coli swimming near a sinusoidal surface, and show that the accumulation of bacteria is determined by the characteristic curvature of the surface. For low curvatures, cells swim along the surface due to steric alignment and are ejected from the surface when they reach the peak of the sinusoid. Increasing curvature enhances this effect and reduces the density of bacteria in the curved surface. However, for curvatures larger than κ^{*}≈0.25µm^{-1}, bacteria become trapped in the valleys, where they can remain for long periods of time. Minimal simulations considering only steric interactions with the surface reproduce these results and give insights into the physical mechanisms defining the critical curvature, which is found to scale with the inverse of the bacterial length. We show that for curvatures larger than κ^{*}, the otherwise stable alignment with the wall becomes unstable while the stable orientation is now perpendicular to the wall, thus predicting accurately the onset of trapping at the valleys.
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Affiliation(s)
- Benjamín Pérez-Estay
- Departamento de Física, FCFM, Universidad de Chile, Av. Beauchef 850, 8370458 Santiago, Chile
- Laboratoire PMMH-ESPCI Paris, PSL Research University, Sorbonne University, University Paris-Diderot, 7, Quai Saint-Bernard, 75005 Paris, France
| | - María Luisa Cordero
- Departamento de Física, FCFM, Universidad de Chile, Av. Beauchef 850, 8370458 Santiago, Chile
| | - Néstor Sepúlveda
- School of Engineering and Sciences, Universidad Adolfo Ibáñez, Diagonal las Torres 2640, Peñalolén, 7941169 Santiago, Chile
| | - Rodrigo Soto
- Departamento de Física, FCFM, Universidad de Chile, Av. Beauchef 850, 8370458 Santiago, Chile
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Niepa THR, Locke LW, Corcoran TE, Lee JS. Editorial: Mechanobiology of biofilms and associated host -pathogen interactions. Front Cell Infect Microbiol 2024; 14:1416131. [PMID: 38716197 PMCID: PMC11074442 DOI: 10.3389/fcimb.2024.1416131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 06/19/2024] Open
Affiliation(s)
- Tagbo H R Niepa
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Landon W Locke
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Timothy E Corcoran
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Janet S Lee
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, United States
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Wnorowska U, Łysik D, Piktel E, Zakrzewska M, Okła S, Lesiak A, Spałek J, Mystkowska J, Savage PB, Janmey P, Fiedoruk K, Bucki R. Ceragenin-mediated disruption of Pseudomonas aeruginosa biofilms. PLoS One 2024; 19:e0298112. [PMID: 38346040 PMCID: PMC10861078 DOI: 10.1371/journal.pone.0298112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/16/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Microbial biofilms, as a hallmark of cystic fibrosis (CF) lung disease and other chronic infections, remain a desirable target for antimicrobial therapy. These biopolymer-based viscoelastic structures protect pathogenic organisms from immune responses and antibiotics. Consequently, treatments directed at disrupting biofilms represent a promising strategy for combating biofilm-associated infections. In CF patients, the viscoelasticity of biofilms is determined mainly by their polymicrobial nature and species-specific traits, such as Pseudomonas aeruginosa filamentous (Pf) bacteriophages. Therefore, we examined the impact of microbicidal ceragenins (CSAs) supported by mucolytic agents-DNase I and poly-aspartic acid (pASP), on the viability and viscoelasticity of mono- and bispecies biofilms formed by Pf-positive and Pf-negative P. aeruginosa strains co-cultured with Staphylococcus aureus or Candida albicans. METHODS The in vitro antimicrobial activity of ceragenins against P. aeruginosa in mono- and dual-species cultures was assessed by determining minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). Inhibition of P. aeruginosa mono- and dual-species biofilms formation by ceragenins alone and in combination with DNase I or poly-aspartic acid (pASP) was estimated by the crystal violet assay. Additionally, the viability of the biofilms was measured by colony-forming unit (CFU) counting. Finally, the biofilms' viscoelastic properties characterized by shear storage (G') and loss moduli (G"), were analyzed with a rotational rheometer. RESULTS Our results demonstrated that ceragenin CSA-13 inhibits biofilm formation and increases its fluidity regardless of the Pf-profile and species composition; however, the Pf-positive biofilms are characterized by elevated viscosity and elasticity parameters. CONCLUSION Due to its microbicidal and viscoelasticity-modifying properties, CSA-13 displays therapeutic potential in biofilm-associated infections, especially when combined with mucolytic agents.
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Affiliation(s)
- Urszula Wnorowska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Dawid Łysik
- Institute of Biomedical Engineering, Bialystok University of Technology, Bialystok, Poland
| | - Ewelina Piktel
- Independent Laboratory of Nanomedicine, Medical University of Białystok, Białystok, Poland
| | - Magdalena Zakrzewska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Sławomir Okła
- Institute of Medical Sciences, Collegium Medicum, Jan Kochanowski University of Kielce, Kielce, Poland
| | - Agata Lesiak
- Institute of Medical Sciences, Collegium Medicum, Jan Kochanowski University of Kielce, Kielce, Poland
| | - Jakub Spałek
- Institute of Medical Sciences, Collegium Medicum, Jan Kochanowski University of Kielce, Kielce, Poland
| | - Joanna Mystkowska
- Institute of Biomedical Engineering, Bialystok University of Technology, Bialystok, Poland
| | - Paul B. Savage
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, United States of America
| | - Paul Janmey
- Department of Physiology and Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Krzysztof Fiedoruk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
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Oropallo A, Rao AS, Del Pin C, Ranire‐Maguire M, Mathew A. An objective comparative study of non-surgical cleansing techniques and cleanser types in bacterial burden management. Int Wound J 2024; 21:e14730. [PMID: 38332560 PMCID: PMC10853581 DOI: 10.1111/iwj.14730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/17/2024] [Accepted: 01/21/2024] [Indexed: 02/10/2024] Open
Abstract
Cleansing is a vital component of effective wound hygiene and biofilm management, often accomplished through vigorous mechanical action or through soaking with moistened gauze. In the present study, a quantitative comparison of the effectiveness of different cleansing techniques and solutions in removing bacteria was conducted on 71 chronic wounds using bacterial fluorescence imaging as a real-time diagnostic for moderate to high bacterial loads. Vigorous gauze cleansing for 30 s proved most effective by reducing bacterial fluorescence by 33.99%, surpassing 10-min soaking in bacterial reduction (13.24%). Among different cleansers, no statistically significant differences in effectiveness were observed, but povidone-iodine showed the strongest trend towards bacterial reduction. Sub-analysis highlighted the superiority of antiseptic cleansers over saline and gentle soap (-33.30% vs. -1.80% bacterial reduction respectively). Five percent acetic acid was also shown to be more effective in removing specific bacterial strains (Pseudomonas aeruginosa). Findings from studies like this contribute to refining wound hygiene guidelines and clinical algorithms for bacterial and biofilm management.
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Affiliation(s)
- Alisha Oropallo
- Northwell Health Comprehensive Wound Health Center and HyperbaricsLake SuccessNew YorkUSA
- Donald and Barbara School of Medicine, Hofstra University/Northwell, Feinstein Institutes for Medical ResearchHempsteadNew YorkUSA
| | - Amit S. Rao
- Northwell Health Comprehensive Wound Health Center and HyperbaricsLake SuccessNew YorkUSA
| | - Christina Del Pin
- Northwell Health Comprehensive Wound Health Center and HyperbaricsLake SuccessNew YorkUSA
- Donald and Barbara School of Medicine, Hofstra University/Northwell, Feinstein Institutes for Medical ResearchHempsteadNew YorkUSA
| | - Marisa Ranire‐Maguire
- Northwell Health Comprehensive Wound Health Center and HyperbaricsLake SuccessNew YorkUSA
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Prabhukhot GS, Eggleton CD, Patel J. Multispecies Bacterial Biofilms and Their Evaluation Using Bioreactors. Foods 2023; 12:4495. [PMID: 38137299 PMCID: PMC10742677 DOI: 10.3390/foods12244495] [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: 09/26/2023] [Revised: 11/20/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
Pathogenic biofilm formation within food processing industries raises a serious public health and safety concern, and places burdens on the economy. Biofilm formation on equipment surfaces is a rather complex phenomenon, wherein multiple steps are involved in bacterial biofilm formation. In this review we discuss the stages of biofilm formation, the existing literature on the impact of surface properties and shear stress on biofilms, types of bioreactors, and antimicrobial coatings. The review underscores the significance of prioritizing biofilm prevention strategies as a first line of defense, followed by control measures. Utilizing specific biofilm eradication strategies as opposed to a uniform approach is crucial because biofilms exhibit different behavioral outcomes even amongst the same species when the environmental conditions change. This review is geared towards biofilm researchers and food safety experts, and seeks to derive insights into the scope of biofilm formation, prevention, and control. The use of suitable bioreactors is paramount to understanding the mechanisms of biofilm formation. The findings provide useful information to researchers involved in bioreactor selection for biofilm investigation, and food processors in surfaces with novel antimicrobial coatings, which provide minimal bacterial attachment.
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Affiliation(s)
- Grishma S. Prabhukhot
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, USA; (G.S.P.); (C.D.E.)
| | - Charles D. Eggleton
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, USA; (G.S.P.); (C.D.E.)
| | - Jitendra Patel
- US Department of Agriculture, Agricultural Research Service, Environmental and Microbial Food Safety Laboratory, Beltsville, MD 20705, USA
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7
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Ausbacher D, Miller LA, Goeres DM, Stewart PS, Strøm MB, Fallarero A. α,α-disubstituted β-amino amides eliminate Staphylococcus aureus biofilms by membrane disruption and biomass removal. Biofilm 2023; 6:100151. [PMID: 37662850 PMCID: PMC10474319 DOI: 10.1016/j.bioflm.2023.100151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 08/12/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Bacterial biofilms account for up to 80% of all infections and complicate successful therapies due to their intrinsic tolerance to antibiotics. Biofilms also cause serious problems in the industrial sectors, for instance due to the deterioration of metals or microbial contamination of products. Efforts are put in finding novel strategies in both avoiding and fighting biofilms. Biofilm control is achieved by killing and/or removing biofilm or preventing transition to the biofilm lifestyle. Previous research reported on the anti-biofilm potency of α,α-disubstituted β-amino amides A1, A2 and A3, which are small antimicrobial peptidomimetics with a molecular weight below 500 Da. In the current study it was investigated if these derivatives cause a fast disintegration of biofilm bacteria and removal of Staphylococcus aureus biofilms. One hour incubation of biofilms with all three derivatives resulted in reduced metabolic activity and membrane permeabilization in S. aureus (ATCC 25923) biofilms. Bactericidal properties of these derivatives were attributed to a direct effect on membranes of biofilm bacteria. The green fluorescence protein expressing Staphylococcus aureus strain AH2547 was cultivated in a CDC biofilm reactor and utilized for disinfectant efficacy testing of A3, following the single tube method (American Society for Testing and Materials designation number E2871). A3 at a concentration of 90 μM acted as fast as 100 μM chlorhexidine and was equally effective. Confocal laser scanning microscopy studies showed that chlorhexidine treatment lead to fluorescence fading indicating membrane permeabilization but did not cause biomass removal. In contrast, A3 treatment caused a simultaneous biofilm fluorescence loss and biomass removal. These dual anti-biofilm properties make α,α-disubstituted β-amino amides promising scaffolds in finding new control strategies against recalcitrant biofilms.
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Affiliation(s)
- Dominik Ausbacher
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, UiT The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Lindsey A. Miller
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Philip S. Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Morten B. Strøm
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, UiT The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Adyary Fallarero
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014, Helsinki, Finland
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Wells MJ, Currie H, Gordon VD. Physiological Concentrations of Calcium Interact with Alginate and Extracellular DNA in the Matrices of Pseudomonas aeruginosa Biofilms to Impede Phagocytosis by Neutrophils. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17050-17058. [PMID: 37972353 PMCID: PMC10764079 DOI: 10.1021/acs.langmuir.3c01637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa (P. aeruginosa) is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study, we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro, and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple-particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase or DNase I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in nontrivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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Zhou X, Wells MJ, Gordon VD. Incorporation of collagen into Pseudomonas aeruginosa and Staphylococcus aureus biofilms impedes phagocytosis by neutrophils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.25.564018. [PMID: 37961328 PMCID: PMC10634824 DOI: 10.1101/2023.10.25.564018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Biofilms are communities of microbes embedded in a matrix of extracellular polymeric substances (EPS). Matrix components can be produced by biofilm organisms and can also originate from the environment and then be incorporated into the biofilm. For example, we have recently shown that collagen, a host-produced protein that is abundant in many different infection sites, can be taken up into the biofilm matrix, altering biofilm mechanics. The biofilm matrix protects bacteria from clearance by the immune system, and some of that protection likely arises from the mechanical properties of the biofilm. Pseudomonas aeruginosa and Staphylococcus aureus are common human pathogens notable for forming biofilm infections in anatomical sites rich in collagen. Here, we show that the incorporation of Type I collagen into P. aeruginosa and S. aureus biofilms significantly hinders phagocytosis of biofilm bacteria by human neutrophils. However, enzymatic treatment with collagenase, which breaks down collagen, can partly or entirely negate the protective effect of collagen and restore the ability of neutrophils to engulf biofilm bacteria. From these findings, we suggest that enzymatic degradation of host materials may be a potential way to compromise biofilm infections and enhance the efficacy of the host immune response without promoting antibiotic resistance. Such an approach might be beneficial both in cases where the infecting species is known and also in cases wherein biofilm components are not readily known, such as multispecies infections or infections by unknown species.
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Affiliation(s)
- Xuening Zhou
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
| | - Marilyn J Wells
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
| | - Vernita D Gordon
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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10
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Wells MJ, Currie H, Gordon VD. Physiological concentrations of calcium interact with alginate and extracellular DNA in the matrices of Pseudomonas aeruginosa biofilms to impede phagocytosis by neutrophils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563605. [PMID: 37961083 PMCID: PMC10634743 DOI: 10.1101/2023.10.23.563605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase and/or DNAse I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in non-trivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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El Masry M, Bhasme P, Mathew-Steiner SS, Smith J, Smeenge T, Roy S, Sen CK. Swine Model of Biofilm Infection and Invisible Wounds. J Vis Exp 2023:10.3791/65301. [PMID: 37395583 PMCID: PMC10655070 DOI: 10.3791/65301] [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] [Indexed: 07/04/2023] Open
Abstract
Biofilm infection is a major contributor to wound chronicity. The establishment of clinically relevant experimental wound biofilm infection requires the involvement of the host immune system. Iterative changes in the host and pathogen during the formation of such clinically relevant biofilm can only occur in vivo. The swine wound model is recognized for its advantages as a powerful pre-clinical model. There are several reported approaches for studying wound biofilms. In vitro and ex vivo systems are deficient in terms of the host immune response. Short-term in vivo studies involve acute responses and, thus, do not allow for biofilm maturation, as is known to occur clinically. The first long-term swine wound biofilm study was reported in 2014. The study recognized that biofilm-infected wounds may close as determined by planimetry, but the skin barrier function of the affected site may fail to be restored. Later, this observation was validated clinically. The concept of functional wound closure was thus born. Wounds closed but deficient in skin barrier function may be viewed as invisible wounds. In this work, we seek to report the methodological details necessary to reproduce the long-term swine model of biofilm-infected severe burn injury, which is clinically relevant and has translational value. This protocol provides detailed guidance on establishing an 8 week wound biofilm infection using P. aeruginosa (PA01). Eight full-thickness burn wounds were created symmetrically on the dorsum of domestic white pigs, which were inoculated with (PA01) at day 3 post-burn; subsequently, noninvasive assessments of the wound healing were conducted at different time points using laser speckle imaging (LSI), high-resolution ultrasound (HUSD), and transepidermal water loss (TEWL). The inoculated burn wounds were covered with a four-layer dressing. Biofilms, as established and confirmed structurally by SEM at day 7 post-inoculation, compromised the functional wound closure. Such an adverse outcome is subject to reversal in response to appropriate interventions.
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Affiliation(s)
- Mohamed El Masry
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Pramod Bhasme
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Shomita S Mathew-Steiner
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Jessica Smith
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Thomas Smeenge
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Sashwati Roy
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine
| | - Chandan K Sen
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine;
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12
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Markale I, Carrel M, Kurz DL, Morales VL, Holzner M, Jiménez-Martínez J. Internal Biofilm Heterogeneities Enhance Solute Mixing and Chemical Reactions in Porous Media. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8065-8074. [PMID: 37205794 DOI: 10.1021/acs.est.2c09082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Bacterial biofilms can form in porous media that are of interest in industrial applications ranging from medical implants to biofilters as well as in environmental applications such as in situ groundwater remediation, where they can be critical locations for biogeochemical reactions. The presence of biofilms modifies porous media topology and hydrodynamics by clogging pores and consequently solutes transport and reactions kinetics. The interplay between highly heterogeneous flow fields found in porous media and microbial behavior, including biofilm growth, results in a spatially heterogeneous biofilm distribution in the porous media as well as internal heterogeneity across the thickness of the biofilm. Our study leverages highly resolved three-dimensional X-ray computed microtomography images of bacterial biofilms in a tubular reactor to numerically compute pore-scale fluid flow and solute transport by considering multiple equivalent stochastically generated internal permeability fields for the biofilm. We show that the internal heterogeneous permeability mainly impacts intermediate velocities when compared with homogeneous biofilm permeability. While the equivalent internal permeability fields of the biofilm do not impact fluid-fluid mixing, they significantly control a fast reaction. For biologically driven reactions such as nutrient or contaminant uptake by the biofilm, its internal permeability field controls the efficiency of the process. This study highlights the importance of considering the internal heterogeneity of biofilms to better predict reactivity in industrial and environmental bioclogged porous systems.
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Affiliation(s)
- Ishaan Markale
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Dorothee L Kurz
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Verónica L Morales
- Department of Civil and Environmental Engineering, University of California Davis, Davis, California 95616-5270, United States
| | - Markus Holzner
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- WSL, Swiss Federal Institute of Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland
| | - Joaquín Jiménez-Martínez
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland
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13
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Wells M, Schneider R, Bhattarai B, Currie H, Chavez B, Christopher G, Rumbaugh K, Gordon V. Perspective: The viscoelastic properties of biofilm infections and mechanical interactions with phagocytic immune cells. Front Cell Infect Microbiol 2023; 13:1102199. [PMID: 36875516 PMCID: PMC9978752 DOI: 10.3389/fcimb.2023.1102199] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/24/2023] [Indexed: 02/18/2023] Open
Abstract
Biofilms are viscoelastic materials that are a prominent public health problem and a cause of most chronic bacterial infections, in large part due to their resistance to clearance by the immune system. Viscoelastic materials combine both solid-like and fluid-like mechanics, and the viscoelastic properties of biofilms are an emergent property of the intercellular cohesion characterizing the biofilm state (planktonic bacteria do not have an equivalent property). However, how the mechanical properties of biofilms are related to the recalcitrant disease that they cause, specifically to their resistance to phagocytic clearance by the immune system, remains almost entirely unstudied. We believe this is an important gap that is ripe for a large range of investigations. Here we present an overview of what is known about biofilm infections and their interactions with the immune system, biofilm mechanics and their potential relationship with phagocytosis, and we give an illustrative example of one important biofilm-pathogen (Pseudomonas aeruginosa) which is the most-studied in this context. We hope to inspire investment and growth in this relatively-untapped field of research, which has the potential to reveal mechanical properties of biofilms as targets for therapeutics meant to enhance the efficacy of the immune system.
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Affiliation(s)
- Marilyn Wells
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Rebecca Schneider
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Bikash Bhattarai
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Hailey Currie
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Bella Chavez
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Gordon Christopher
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Kendra Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Vernita Gordon
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX, United States
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, TX, United States
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14
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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: 9] [Impact Index Per Article: 9.0] [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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15
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Faucher N, Fromantin I, Barrois B, Carvalho P, Chignon-Sicard B, Chopin A, Duteille F, Jurus C, Meaume S, Kern J, Philippe A, Vasseur P. [Not Available]. SOINS; LA REVUE DE REFERENCE INFIRMIERE 2022; 67:18-20. [PMID: 36180171 DOI: 10.1016/s0038-0814(22)00235-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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16
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Aristotelous AC. Biofilm neutrophils interactions under hypoxia: A mathematical modeling study. Math Biosci 2022; 352:108893. [PMID: 36029807 DOI: 10.1016/j.mbs.2022.108893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 11/18/2022]
Abstract
Neutrophils are important to the defense of the host against bacterial infection. Pathogens and the immune system cells create via respiration, a hypoxic environment in infected regions. Hypoxic conditions affect both the neutrophil's ability to eradicate the infection and also change the behavior of the bacterial-pathogens by eliciting the production of various virulence factors, the creation of bacterial biofilm and the initialization of anaerobic metabolism. In this work interactions of bacterial biofilm and neutrophils are studied in a domain where oxygen is diffusing into the environment and is being consumed by biofilm. Within a hypoxic environment, bacteria grow anaerobically and secrete higher levels of toxin that diffuses and lyses neutrophils. A mathematical model explicitly representing the biofilm volume fraction, oxygen, and diffusive virulence factors (toxin) as well as killing of bacteria by neutrophils is developed and studied first in 1D and then in 2D. Stability analysis and numerical simulations showing the effects of oxygen and toxin concentration on neutrophil-bacteria interactions are presented to identify different possible scenarios that can lead to elimination of the infection or its persistence as a chronic infection. Specifically, when bacteria are allowed to utilize anaerobic breathing and or to produce toxin, their fitness is enhanced against neutrophils attacks. A possible insight on how virulent bacterial colonies can synergistically resist neutrophils and survive is presented.
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Affiliation(s)
- Andreas C Aristotelous
- Department of Mathematics, Buchtel College of Arts and Sciences, The University of Akron, Akron, OH, 44325-4002, USA.
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17
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Duffy HR, Godfrey RW, Williams DL, Ashton NN. A Porcine Model for the Development and Testing of Preoperative Skin Preparations. Microorganisms 2022; 10:837. [PMID: 35630283 PMCID: PMC9146673 DOI: 10.3390/microorganisms10050837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 11/17/2022] Open
Abstract
Clinical preoperative skin preparations (PSPs) do not eradicate skin flora dwelling in the deepest dermal regions. Survivors constitute a persistent infection risk. In search of solutions, we created a porcine model intended for PSP developmental testing. This model employed microbiological techniques sensitive to the deep-dwelling microbial flora as these microorganisms are frequently overlooked when using institutionally-entrenched testing methodologies. Clinical gold-standard PSPs were assessed. Ten Yorkshire pigs were divided into two groups: prepared with either povidone iodine (PVP-I) or chlorhexidine gluconate (CHG) PSP. Bioburdens were calculated on square, 4 cm by 4 cm, full-thickness skin samples homogenized in neutralizing media. Endogenous bioburden of porcine skin (3.3 log10 CFU/cm2) was consistent with natural flora numbers in dry human skin. On-label PSP scrub kits with PVP-I (n = 39) or CHG (n = 40) failed the 2-3 log10-reduction criteria established for PSPs by the Food and Drug Administration (FDA), resulting in a 1.46 log10 and 0.58 log10 reduction, respectively. Porcine dermal microbiota mirrored that of humans, displaying abundant staphylococcal species. Likewise, histological sections showed similarity in hair follicle depths and sebaceous glands (3.2 ± 0.7 mm). These shared characteristics and the considerable fraction of bacteria which survived clinical PSPs make this model useful for developmental work.
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Affiliation(s)
- Hannah R. Duffy
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84112, USA; (H.R.D.); (R.W.G.); (D.L.W.)
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Rose W. Godfrey
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84112, USA; (H.R.D.); (R.W.G.); (D.L.W.)
| | - Dustin L. Williams
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84112, USA; (H.R.D.); (R.W.G.); (D.L.W.)
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
- Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Nicholas N. Ashton
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84112, USA; (H.R.D.); (R.W.G.); (D.L.W.)
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18
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Kay W, Hunt C, Nehring L, Barnum B, Ashton N, Williams D. Biofilm Growth on Simulated Fracture Fixation Plates Using a Customized CDC Biofilm Reactor for a Sheep Model of Biofilm-Related Infection. Microorganisms 2022; 10:microorganisms10040759. [PMID: 35456808 PMCID: PMC9031587 DOI: 10.3390/microorganisms10040759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 02/04/2023] Open
Abstract
Most animal models of infection utilize planktonic bacteria as initial inocula. However, this may not accurately mimic scenarios where bacteria in the biofilm phenotype contaminate a site at the point of injury. We developed a modified CDC biofilm reactor in which biofilms can be grown on the surface of simulated fracture fixation plates. Multiple reactor runs were performed and demonstrated that monomicrobial biofilms of a clinical strain of methicillin-resistant Staphylococcus aureus, S. aureus ATCC 6538, and Pseudomonas aeruginosa ATCC 27853 consistently developed on fixation plates. We also identified a method by which to successfully grow polymicrobial biofilms of S. aureus ATCC 6538 and P. aeruginosa ATCC 27853 on fixation plates. This customized reactor can be used to grow biofilms on simulated fracture fixation plates that can be inoculated in animal models of biofilm implant-related infection that, for example, mimic open fracture scenarios. The reactor provides a method for growing biofilms that can be used as initial inocula and potentially improve the testing and development of antibiofilm technologies.
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Affiliation(s)
- Walker Kay
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108, USA; (W.K.); (C.H.); (L.N.); (N.A.)
| | - Connor Hunt
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108, USA; (W.K.); (C.H.); (L.N.); (N.A.)
| | - Lisa Nehring
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108, USA; (W.K.); (C.H.); (L.N.); (N.A.)
| | - Brian Barnum
- Purgo Scientific, LLC, South Jordan, UT 84095, USA;
| | - Nicholas Ashton
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108, USA; (W.K.); (C.H.); (L.N.); (N.A.)
- Purgo Scientific, LLC, South Jordan, UT 84095, USA;
| | - Dustin Williams
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108, USA; (W.K.); (C.H.); (L.N.); (N.A.)
- Purgo Scientific, LLC, South Jordan, UT 84095, USA;
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
- Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Correspondence:
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19
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Goodman SD, Bakaletz LO. Bacterial Biofilms Utilize an Underlying Extracellular DNA Matrix Structure That Can Be Targeted for Biofilm Resolution. Microorganisms 2022; 10:microorganisms10020466. [PMID: 35208922 PMCID: PMC8878592 DOI: 10.3390/microorganisms10020466] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 12/16/2022] Open
Abstract
Bacterial biofilms contribute significantly to the antibiotic resistance, pathogenesis, chronicity and recurrence of bacterial infections. Critical to the stability and survival of extant biofilms is the extracellular DNA (eDNA)-dependent matrix which shields the resident bacteria from hostile environments, allows a sessile metabolic state, but also encourages productive interactions with biofilm-inclusive bacteria. Given the importance of the eDNA, approaches to this area of research have been to target not just the eDNA, but also the additional constituent structural components which appear to be widespread. Chief among these is a ubiquitous two-member family of bacterial nucleoid associated proteins (the DNABII proteins) responsible for providing structural integrity to the eDNA and thereby the biofilm. Moreover, this resultant novel eDNA-rich secondary structure can also be targeted for disruption. Here, we provide an overview of both what is known about the eDNA-dependent matrix, as well as the resultant means that have resulted in biofilm resolution. Results obtained to date have been highly supportive of continued development of DNABII-targeted approaches, which is encouraging given the great global need for improved methods to medically manage, or ideally prevent biofilm-dependent infections, which remains a highly prevalent burden worldwide.
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Dhivya R, Rajakrishnapriya VC, Sruthi K, Chidanand DV, Sunil CK, Rawson A. Biofilm combating in the food industry: Overview, non‐thermal approaches, and mechanisms. J FOOD PROCESS PRES 2022. [DOI: 10.1111/jfpp.16282] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- R. Dhivya
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - V. C. Rajakrishnapriya
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - K. Sruthi
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - D. V. Chidanand
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - C. K. Sunil
- Department of Food Engineering National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - Ashish Rawson
- Department of Food Safety and Quality Testing National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
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21
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Jørgensen E, Bjarnsholt T, Jacobsen S. Biofilm and Equine Limb Wounds. Animals (Basel) 2021; 11:2825. [PMID: 34679846 PMCID: PMC8532864 DOI: 10.3390/ani11102825] [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: 07/08/2021] [Revised: 09/14/2021] [Accepted: 09/23/2021] [Indexed: 01/01/2023] Open
Abstract
In chronic wounds in humans, biofilm formation and wound chronicity are linked, as biofilms contribute to chronic inflammation and delayed healing. Biofilms are aggregates of bacteria, and living as biofilms is the default mode of bacterial life; within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. In horses, delayed healing is more commonly seen in limb wounds than body wounds. Chronic inflammation and hypoxia are the main characteristics of delayed wound healing in equine limbs, and biofilms might also contribute to this healing pattern in horses. However, biofilm formation in equine wounds has been studied to a very limited degree. Biofilms have been detected in equine traumatic wounds, and recent experimental models have shown that biofilms protract the healing of equine limb wounds. Detection of biofilms within wounds necessitates advanced techniques that are not available in routine diagnostic yet. However, infections with biofilm should be suspected in equine limb wounds not healing as expected, as they are in human wounds. Treatment should be based on repeated debridement and application of topical antimicrobial therapy.
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Affiliation(s)
- Elin Jørgensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark;
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark;
- Department of Clinical Microbiology, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Stine Jacobsen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2630 Taastrup, Denmark;
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Bjarnsholt T, Whiteley M, Rumbaugh KP, Stewart PS, Jensen PØ, Frimodt-Møller N. The importance of understanding the infectious microenvironment. THE LANCET. INFECTIOUS DISEASES 2021; 22:e88-e92. [PMID: 34506737 DOI: 10.1016/s1473-3099(21)00122-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 01/25/2021] [Accepted: 02/12/2021] [Indexed: 12/12/2022]
Abstract
Standard doses of antibiotics do not efficiently treat chronic infections of the soft tissue and bone. In this Personal View, we advocate for improving treatment of these infections by taking the infectious microenvironment into account. The infectious microenvironment can cause sensitive bacteria to lose their susceptibility to antibiotics that are effective in standard laboratory susceptibility testing. We propose that bacteria behave substantially different in standard laboratory conditions than they do in actual infections. The infectious microenvironment could impose changes in growth and metabolic activity that result in increased protection against antibiotics. Therefore, we advocate that improved antibiotic treatment of chronic infection is achievable when antibiotics are recommended on the basis of susceptibility testing in relevant in vitro conditions that resemble actual infectious microenvironments. We recommend establishing knowledge of the relevant conditions of the chemical and physical composition of the infectious microenvironment. Recent advances in RNA sequencing, metabolomics, and microscopy have made it possible for the characterisation of the microenvironment of infections and to validate the clinical relevance of in vitro conditions to actual infections.
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Affiliation(s)
- Thomas Bjarnsholt
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark; Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | - Marvin Whiteley
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA; Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
| | - Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Peter Ø Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark; Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Frimodt-Møller
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
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24
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Ghosh UU, Ali H, Ghosh R, Kumar A. Bacterial streamers as colloidal systems: Five grand challenges. J Colloid Interface Sci 2021; 594:265-278. [PMID: 33765646 DOI: 10.1016/j.jcis.2021.02.102] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/21/2022]
Abstract
Bacteria can thrive in biofilms, which are intricately organized communities with cells encased in a self-secreted matrix of extracellular polymeric substances (EPS). Imposed hydrodynamic stresses can transform this active colloidal dispersion of bacteria and EPS into slender thread-like entities called streamers. In this perspective article, the reader is introduced to the world of such deformable 'bacteria-EPS' composites that are a subclass of the generic flow-induced colloidal structures. While bacterial streamers have been shown to form in a variety of hydrodynamic conditions (turbulent and creeping flows), its abiotic analogues have only been demonstrated in low Reynolds number (Re < 1) particle-laden polymeric flows. Streamers are relevant to a variety of situations ranging from natural formations in caves and river beds to clogging of biomedical devices and filtration membranes. A critical review of the relevant biophysical aspects of streamer formation phenomena and unique attributes of its material behavior are distilled to unveil five grand scientific challenges. The coupling between colloidal hydrodynamics, device geometry and streamer formation are highlighted.
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Affiliation(s)
- Udita U Ghosh
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
| | - Hessein Ali
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Ranajay Ghosh
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA.
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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25
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Both Pseudomonas aeruginosa and Candida albicans Accumulate Greater Biomass in Dual-Species Biofilms under Flow. mSphere 2021; 6:e0041621. [PMID: 34160236 PMCID: PMC8265656 DOI: 10.1128/msphere.00416-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Microbe-microbe interactions can strongly influence growth and biofilm formation kinetics. For Pseudomonas aeruginosa and Candida albicans, which are found together in diverse clinical sites, including urinary and intravenous catheters and the lungs of individuals with cystic fibrosis (CF), we compared the kinetics of biofilm formation by each species in dual-species and single-species biofilms. We engineered fluorescent protein constructs for P. aeruginosa (producing mKO-κ) and C. albicans (producing mKate2) that did not alter growth and enabled single-cell resolution imaging by live-sample microscopy. Using these strains in an optically clear derivative of synthetic CF sputum medium, we found that both P. aeruginosa and C. albicans displayed increased biovolume accumulation—by three- and sixfold, respectively—in dual-species biofilms relative to single-species biofilms. This result was specific to the biofilm environment, as enhanced growth was not observed in planktonic cocultures. Stimulation of C. albicans biofilm formation occurred regardless of whether P. aeruginosa was added at the time of fungal inoculation or 24 h after the initiation of biofilm development. P. aeruginosa biofilm increases in cocultures did not require the Pel extracellular polysaccharide, phenazines, and siderophores known to influence C. albicans. P. aeruginosa mutants lacking Anr, LasR, and BapA were not significantly stimulated by C. albicans, but they still promoted a significant enhancement of biofilm development of the fungus, suggesting a fungal response to the presence of bacteria. Last, we showed that a set of P. aeruginosa clinical isolates also prompted an increase of biovolume by C. albicans in coculture. IMPORTANCE There is an abundance of work on both P. aeruginosa and C. albicans in isolation, and quite some work as well on the way these two microbes interact. These studies do not, however, consider biofilm environments under flow, and our results here show that the expected outcome of interaction between these two pathogens can actually be reversed under flow, from pure antagonism to an increase in biomass on the part of both. Our work also highlights the importance of cellular-scale spatial structure in biofilms for understanding multispecies population dynamics.
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Bjarnsholt T, Mastroianni E, Kirketerp-Møller K, Stewart PS, Mähr AM, Domínguez Cabañes A, Nørager R. The impact of mental models on the treatment and research of chronic infections due to biofilms. APMIS 2021; 129:598-606. [PMID: 34120370 DOI: 10.1111/apm.13163] [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: 12/06/2020] [Accepted: 05/30/2021] [Indexed: 01/14/2023]
Abstract
Research on biofilms is predominantly made in in vitro contexts. However, in vivo observation of biofilms in human chronic infections shows distinct differences compared to in vitro biofilm growth. This could imply the use of an inadequate mental model both in research and healthcare practices. Drawing on knowledge from the cognitive sciences, we hypothesise that the predominance of in vitro research on biofilms is skewed towards a mental model promoting wrong inferences for researchers and healthcare professionals (HCPs) in the in vivo context. To explore the prevalence of such a mental model, we carried out a qualitative image analysis in which biofilm illustrations from a Google image search were coded for typical in vitro or in vivo characteristics. Further, to investigate potential misinformed and unhelpful clinical interventions related to biofilms, we conducted a quantitative questionnaire among HCPs. The questions were designed to test whether knowledge about in vitro biofilms was used in an in vivo context. This questionnaire was analysed through a chi-squared test. Most biofilm illustrations were consistent with the in vitro model. A statistical analysis of survey responses revealed that HCPs have adequate knowledge about biofilm but often respond incorrectly when asked to apply their knowledge to in vivo contexts. The outcome of this research points to a prevalent and consolidated mental model derived from in vitro observations. This model has likely been made dominant by HCPs' frequent exposure to visual depictions in articles and presentations. The prevalence of the in vitro model sets up the possibility of erroneous claims when the in vitro model is inadequately applied to in vivo contexts. This has potential implications for HCPs working in fields involving biofilm, such as wound care treatment.
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Affiliation(s)
- Thomas Bjarnsholt
- Costerton Biofilm Centre, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | | | | | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, USA
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27
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Abraham S, Kaufman Y, Perreault F, Young R, Bar-Zeev E. Bursting out: linking changes in nanotopography and biomechanical properties of biofilm-forming Escherichia coli to the T4 lytic cycle. NPJ Biofilms Microbiomes 2021; 7:26. [PMID: 33731698 PMCID: PMC7969764 DOI: 10.1038/s41522-021-00195-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/20/2021] [Indexed: 11/09/2022] Open
Abstract
The bacteriophage infection cycle has been extensively studied, yet little is known about the nanostructure and mechanical changes that lead to bacterial lysis. Here, atomic force microscopy was used to study in real time and in situ the impact of the canonical phage T4 on the nanotopography and biomechanics of irreversibly attached, biofilm-forming E. coli cells. The results show that in contrast to the lytic cycle in planktonic cells, which ends explosively, anchored cells that are in the process of forming a biofilm undergo a more gradual lysis, developing distinct nanoscale lesions (~300 nm in diameter) within the cell envelope. Furthermore, it is shown that the envelope rigidity and cell elasticity decrease (>50% and >40%, respectively) following T4 infection, a process likely linked to changes in the nanostructure of infected cells. These insights show that the well-established lytic pathway of planktonic cells may be significantly different from that of biofilm-forming cells. Elucidating the lysis paradigm of these cells may advance biofilm removal and phage therapeutics.
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Affiliation(s)
- Shiju Abraham
- Zuckerberg Institute for Water Research, The Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Yair Kaufman
- Zuckerberg Institute for Water Research, The Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boqer Campus, Midreshet Ben-Gurion, Israel.
| | - François Perreault
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - Ry Young
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
- Texas A&M AgriLife, College Station, TX, USA
| | - Edo Bar-Zeev
- Zuckerberg Institute for Water Research, The Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boqer Campus, Midreshet Ben-Gurion, Israel.
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28
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Alonso-Caballero A, Echelman DJ, Tapia-Rojo R, Haldar S, Eckels EC, Fernandez JM. Protein folding modulates the chemical reactivity of a Gram-positive adhesin. Nat Chem 2021; 13:172-181. [PMID: 33257887 PMCID: PMC7858226 DOI: 10.1038/s41557-020-00586-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 09/29/2020] [Indexed: 01/30/2023]
Abstract
Gram-positive bacteria colonize mucosal tissues, withstanding large mechanical perturbations such as coughing, which generate shear forces that exceed the ability of non-covalent bonds to remain attached. To overcome these challenges, the pathogen Streptococcus pyogenes utilizes the protein Cpa, a pilus tip-end adhesin equipped with a Cys-Gln thioester bond. The reactivity of this bond towards host surface ligands enables covalent anchoring; however, colonization also requires cell migration and spreading over surfaces. The molecular mechanisms underlying these seemingly incompatible requirements remain unknown. Here we demonstrate a magnetic tweezers force spectroscopy assay that resolves the dynamics of the Cpa thioester bond under force. When folded at forces <6 pN, the Cpa thioester bond reacts reversibly with amine ligands, which are common in inflammation sites; however, mechanical unfolding and exposure to forces >6 pN block thioester reformation. We hypothesize that this folding-coupled reactivity switch (termed a smart covalent bond) could allow the adhesin to undergo binding and unbinding to surface ligands under low force and remain covalently attached under mechanical stress.
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Affiliation(s)
- Alvaro Alonso-Caballero
- Department of Biological Sciences, Columbia University, NY
10027, USA,Correspondence and request of material should be
addressed to A.A-C.:
| | | | - Rafael Tapia-Rojo
- Department of Biological Sciences, Columbia University, NY
10027, USA
| | - Shubhasis Haldar
- Department of Biological Sciences, Columbia University, NY
10027, USA
| | - Edward C. Eckels
- Department of Biological Sciences, Columbia University, NY
10027, USA
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29
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The establishment of the CBE launched biofilms as a field of specialized research. Biofilm 2021; 2:100020. [PMID: 33447806 PMCID: PMC7798467 DOI: 10.1016/j.bioflm.2020.100020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/25/2019] [Accepted: 02/01/2020] [Indexed: 01/17/2023] Open
Abstract
The Center for Biofilm Engineering was the first center of excellence focused on biofilms and was originally funded through the Engineering Research Center Program from the U.S. National Science Foundation. After almost 30 years, biofilm continues to be a stand-alone scientific topic of inquiry that has broad implications for fundamental and applied science and engineering of bio-systems. However, much remains to be done, not only for research discovery but also education and outreach, to increase and grow the biofilm paradigm as well as our understanding of the microbial world.
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30
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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: 65] [Impact Index Per Article: 16.3] [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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31
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Pham DQ, Bryant SJ, Cheeseman S, Huang LZY, Bryant G, Dupont MF, Chapman J, Berndt CC, Vongsvivut JP, Crawford RJ, Truong VK, Ang ASM, Elbourne A. Micro- to nano-scale chemical and mechanical mapping of antimicrobial-resistant fungal biofilms. NANOSCALE 2020; 12:19888-19904. [PMID: 32985644 DOI: 10.1039/d0nr05617k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A fungal biofilm refers to the agglomeration of fungal cells surrounded by a polymeric extracellular matrix (ECM). The ECM is composed primarily of polysaccharides that facilitate strong surface adhesion, proliferation, and cellular protection from the surrounding environment. Biofilms represent the majority of known microbial communities, are ubiquitous, and are found on a multitude of natural and synthetic surfaces. The compositions, and in-turn nanomechanical properties, of fungal biofilms remain poorly understood, because these systems are complex, composed of anisotropic cellular and extracellular material, and importantly are species and environment dependent. Therefore, genomic variation, and/or mutations, as well as environmental and growth factors can change the composition of a fungal cell's biofilm. In this work, we probe the physico-mechanical and biochemical properties of two fungal species, Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans), as well as two antifungal resistant sub-species of C. neoformans, fluconazole-resistant C. neoformans (FlucRC. neoformans) and amphotericin B-resistant C. neoformans (AmBRC. neoformans). A new experimental methodology of characterization is proposed, employing a combination of atomic force microscopy (AFM), instrumented nanoindentation, and Synchrotron ATR-FTIR measurements. This allowed the nano-mechanical and chemical characterisation of each fungal biofilm.
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Affiliation(s)
- Duy Quang Pham
- Surface Engineering for Advanced Materials (SEAM), Department of Mechanical and Production Design Engineering, Swinburne University of Technology, Hawthorn, Australia.
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32
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Kavanaugh JS, Leidal KG, Nauseef WM, Horswill AR. Cathepsin G Degrades Staphylococcus aureus Biofilms. J Infect Dis 2020; 223:1865-1869. [PMID: 32995850 DOI: 10.1093/infdis/jiaa612] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 09/25/2020] [Indexed: 12/22/2022] Open
Abstract
Polymorphonuclear leukocytes (PMN) phagocytose and kill individual bacteria but are far less efficient when challenged with bacterial aggregates. Consequently, growth within a biofilm affords Staphylococcus aureus some protection but PMN penetrate S. aureus biofilms and phagocytose bacteria, suggesting that enzymes released through neutrophil degranulation degrade biofilms into fragments small enough for phagocytosis. Here we show that the capacity of PMN to invade biofilms depended largely on the activity of secreted cathepsin G.
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Affiliation(s)
- Jeffrey S Kavanaugh
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kevin G Leidal
- Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - William M Nauseef
- Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Department of Veterans Affairs, Eastern Colorado Health Care System, Denver, Colorado, USA
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33
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Pandit S, Fazilati M, Gaska K, Derouiche A, Nypelö T, Mijakovic I, Kádár R. The Exo-Polysaccharide Component of Extracellular Matrix is Essential for the Viscoelastic Properties of Bacillus subtilis Biofilms. Int J Mol Sci 2020; 21:ijms21186755. [PMID: 32942569 PMCID: PMC7555405 DOI: 10.3390/ijms21186755] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Bacteria are known to form biofilms on various surfaces. Biofilms are multicellular aggregates, held together by an extracellular matrix, which is composed of biological polymers. Three principal components of the biofilm matrix are exopolysaccharides (EPS), proteins, and nucleic acids. The biofilm matrix is essential for biofilms to remain organized under mechanical stress. Thanks to their polymeric nature, biofilms exhibit both elastic and viscous mechanical characteristics; therefore, an accurate mechanical description needs to take into account their viscoelastic nature. Their viscoelastic properties, including during their growth dynamics, are crucial for biofilm survival in many environments, particularly during infection processes. How changes in the composition of the biofilm matrix affect viscoelasticity has not been thoroughly investigated. In this study, we used interfacial rheology to study the contribution of the EPS component of the matrix to viscoelasticity of Bacillus subtilis biofilms. Two strategies were used to specifically deplete the EPS component of the biofilm matrix, namely (i) treatment with sub-lethal doses of vitamin C and (ii) seamless inactivation of the eps operon responsible for biosynthesis of the EPS. In both cases, the obtained results suggest that the EPS component of the matrix is essential for maintaining the viscoelastic properties of bacterial biofilms during their growth. If the EPS component of the matrix is depleted, the mechanical stability of biofilms is compromised and the biofilms become more susceptible to eradication by mechanical stress.
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Affiliation(s)
- Santosh Pandit
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
| | - Mina Fazilati
- Department of Industrial and Materials Science, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden;
| | - Karolina Gaska
- Department of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UK;
| | - Abderahmane Derouiche
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
| | - Tiina Nypelö
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Wallenberg Wood Science Center, Chalmers, 412 96 Göteborg, Sweden
| | - Ivan Mijakovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
- Correspondence: (I.M.); (R.K.)
| | - Roland Kádár
- Department of Industrial and Materials Science, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Wallenberg Wood Science Center, Chalmers, 412 96 Göteborg, Sweden
- Correspondence: (I.M.); (R.K.)
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34
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Jorge P, Magalhães AP, Grainha T, Alves D, Sousa AM, Lopes SP, Pereira MO. Antimicrobial resistance three ways: healthcare crisis, major concepts and the relevance of biofilms. FEMS Microbiol Ecol 2020; 95:5532357. [PMID: 31305896 DOI: 10.1093/femsec/fiz115] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022] Open
Abstract
Worldwide, infections are resuming their role as highly effective killing diseases, as current treatments are failing to respond to the growing problem of antimicrobial resistance (AMR). The social and economic burden of AMR seems ever rising, with health- and research-related organizations rushing to collaborate on a worldwide scale to find effective solutions. Resistant bacteria are spreading even in first-world nations, being found not only in healthcare-related settings, but also in food and in the environment. In this minireview, the impact of AMR in healthcare systems and the major bacteria behind it are highlighted. Ecological aspects of AMR evolution and the complexity of its molecular mechanisms are explained. Major concepts, such as intrinsic, acquired and adaptive resistance, as well as tolerance and heteroresistance, are also clarified. More importantly, the problematic of biofilms and their role in AMR, namely their main resistance and tolerance mechanisms, are elucidated. Finally, some of the most promising anti-biofilm strategies being investigated are reviewed. Much is still to be done regarding the study of AMR and the discovery of new anti-biofilm strategies. Gladly, considerable research on this topic is generated every day and increasingly concerted actions are being engaged globally to try and tackle this problem.
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Affiliation(s)
- Paula Jorge
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Andreia Patrícia Magalhães
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Tânia Grainha
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Diana Alves
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Ana Margarida Sousa
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Susana Patrícia Lopes
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria Olívia Pereira
- Centre of Biological Engineering, Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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35
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Efficacy of A Poly(MeOEGMA) Brush on the Prevention of Escherichia coli Biofilm Formation and Susceptibility. Antibiotics (Basel) 2020; 9:antibiotics9050216. [PMID: 32365462 PMCID: PMC7277157 DOI: 10.3390/antibiotics9050216] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
Urinary tract infections are one of the most common hospital-acquired infections, and they are often associated with biofilm formation in indwelling medical devices such as catheters and stents. This study aims to investigate the antibiofilm performance of a polymer brush—poly[oligo(ethylene glycol) methyl ether methacrylate], poly(MeOEGMA)—and evaluate its effect on the antimicrobial susceptibility of Escherichia coli biofilms formed on that surface. Biofilms were formed in a parallel plate flow chamber (PPFC) for 24 h under the hydrodynamic conditions prevailing in urinary catheters and stents and challenged with ampicillin. Results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) and glass. The polymer brush reduced by 57% the surface area covered by E. coli after 24 h, as well as the number of total adhered cells. The antibiotic treatment potentiated cell death and removal, and the total cell number was reduced by 88%. Biofilms adapted their architecture, and cell morphology changed to a more elongated form during that period. This work suggests that the poly(MeOEGMA) brush has potential to prevent bacterial adhesion in urinary tract devices like ureteral stents and catheters, as well as in eradicating biofilms developed in these biomedical devices.
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36
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Marx P, Sang Y, Qin H, Wang Q, Guo R, Pfeifer C, Kreth J, Merritt J. Environmental stress perception activates structural remodeling of extant Streptococcus mutans biofilms. NPJ Biofilms Microbiomes 2020; 6:17. [PMID: 32221309 PMCID: PMC7101444 DOI: 10.1038/s41522-020-0128-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/12/2020] [Indexed: 01/28/2023] Open
Abstract
Transcription regulators from the LexA-like Protein Superfamily control a highly diverse assortment of genetic pathways in response to environmental stress. All characterized members of this family modulate their functionality and stability via a strict coordination with the coprotease function of RecA. Using the LexA-like protein IrvR from Streptococcus mutans, we demonstrate an exception to the RecA paradigm and illustrate how this evolutionary innovation has been coopted to diversify the stress responsiveness of S. mutans biofilms. Using a combination of genetics and biophysical measurements, we demonstrate how non-SOS stresses and SOS stresses each trigger separate regulatory mechanisms that stimulate production of a surface lectin responsible for remodeling the viscoelastic properties of extant biofilms during episodes of environmental stress. These studies demonstrate how changes in the external environment or even anti-biofilm therapeutic agents can activate biofilm-specific adaptive mechanisms responsible for bolstering the integrity of established biofilm communities. Such changes in biofilm community structure are likely to play central roles in the notorious recalcitrance of biofilm infections.
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Affiliation(s)
- Patrick Marx
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Yu Sang
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Hua Qin
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Qingjing Wang
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Rongkai Guo
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Carmem Pfeifer
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Jens Kreth
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA ,0000 0000 9758 5690grid.5288.7Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239 USA
| | - Justin Merritt
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA ,0000 0000 9758 5690grid.5288.7Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239 USA
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37
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Murphy C, Atkin L, Swanson T, Tachi M, Tan YK, de Ceniga MV, Weir D, Wolcott R, Ĉernohorská J, Ciprandi G, Dissemond J, James GA, Hurlow J, Lázaro MartÍnez JL, Mrozikiewicz-Rakowska B, Wilson P. Defying hard-to-heal wounds with an early antibiofilm intervention strategy: wound hygiene. J Wound Care 2020; 29:S1-S26. [DOI: 10.12968/jowc.2020.29.sup3b.s1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Christine Murphy
- Vascular Nurse Specialist, The Ottawa Hospital Limb Preservation Centre, Ottawa, Canada
| | - Leanne Atkin
- Vascular Nurse Consultant, Mid Yorkshire Hospitals NHS Trust and University of Huddersfield, UK
| | - Terry Swanson
- Nurse Practitioner, Wound Management, Warrnambool, Victoria, Australia
| | - Masahiro Tachi
- Professor, Department of Plastic and Reconstructive Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Yih Kai Tan
- Director of Vascular Services, Consultant Vascular and Endovascular Surgeon, Changi General Hospital, Singapore
| | - Melina Vega de Ceniga
- Consultant Angiologist, Vascular and Endovascular Surgeon, Galdakao-Usansolo Hospital, Bizkaia, Spain
| | - Dot Weir
- Saratoga Hospital Center for Wound Healing and Hyperbaric Medicine, Saratoga Springs, New York, US
| | | | | | - Guido Ciprandi
- Chief Wound Care Surgical Unit, Division of Plastic and Maxillofacial Surgery, Bambino Gesù Children's Hospital, Research Institute, Rome, Italy
| | - Joachim Dissemond
- Professor of Dermatology and Venerology, University of Essen, Germany
| | - Garth A James
- Associate Research Professor of Chemical and Biological Engineering, Director, Medical Biofilms Laboratory, Center for Biofilm Engineering, Montana State University, Bozeman, Montana, US
| | - Jenny Hurlow
- Wound Specialized Advanced Practice Nurse, Advanced Wound Care, Southaven, Mississippi and West Memphis, Arkansas, US
| | | | - Beata Mrozikiewicz-Rakowska
- Associate Professor, Diabetology and Metabolic Diseases Department, Medical University of Warsaw, Warsaw, Poland
| | - Pauline Wilson
- Clinical Specialist Podiatrist, St James's Hospital, Dublin, Republic of Ireland
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38
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Tan CAZ, Antypas H, Kline KA. Overcoming the challenge of establishing biofilms in vivo: a roadmap for Enterococci. Curr Opin Microbiol 2020; 53:9-18. [PMID: 32062025 DOI: 10.1016/j.mib.2020.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/28/2022]
Abstract
Enterococcus faecalis forms single and mixed-species biofilms on both tissue and medical devices in the host, often under exposure to fluid flow, giving rise to infections that are recalcitrant to treatment. The factors that drive enterococcal biofilm formation in the host, however, remain unclear. Recent reports in other pathogens show how surface sensing by bacteria can trigger the transition from planktonic to sessile lifestyle. Fluid flow can enhance initial adhesion, but also influence quorum sensing. Biofilm-specific factors, as well as biofilm size and extracellular polymeric substances, can compromise opsonization and phagocytosis. Bacterial interspecies synergy can create favorable conditions in the host for biofilm formation. Through these concepts, we define the knowledge gaps in understanding host-associated E. faecalis biofilm formation and propose a roadmap for future investigations.
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Affiliation(s)
- Casandra Ai Zhu Tan
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Haris Antypas
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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In vitro anti-biofilm activity of 14-deoxy-11,12-didehydroandrographolide from Andrographis paniculata against Pseudomonas aeruginosa. Braz J Microbiol 2019; 51:15-27. [PMID: 31691922 DOI: 10.1007/s42770-019-00169-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 10/03/2019] [Indexed: 10/25/2022] Open
Abstract
14-Deoxy-11,12-didehydroandrographolide is a biologically active molecule present in the extract of Andrographis paniculata (Kalmegh), a classic ethnic herbal formula, which has been used for over thousand years as therapeutics to treat numerous infectious diseases like upper respiratory tract infection, urinary tract infection, and many more health issues. The present study is designed to ascertain an inhibitor against biofilm formation from the major metabolites of Andrographis paniculata, because the extract of this herb shows inhibition of bacterial quorum sensing (QS) communication and biofilm development against microorganisms. 14-Deoxy-11,12-didehydroandrographolide at 0.1 mM (sub-MIC dose) with azithromycin (6 μg/mL, sub-MIC) or gentamicin (4 μg/mL, sub-MIC) synergistically inhibits 92% biofilm production by a 48-h treatment against Pseudomonas aeruginosa. Further investigation carried out by atomic force microscopy shows promising reduction in roughness and height of biofilm in the presence of 14-deoxy-11,12-didehydroandrographolide compared with the control group. The content of extracellular polymeric substances, level of pyocyanin production, and synthesis of extracellular protease by P. aeruginosa have also been reduced significantly at around 90% in 14-deoxy-11,12-didehydroandrographolide-treated group. In conclusion, 14-deoxy-11,12-didehydroandrographolide could be used as a drug molecule against biofilm development by inhibiting QS pathway in Pseudomonas aeruginosa.
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Simkins JW, Stewart PS, Codd SL, Seymour JD. Non-invasive imaging of oxygen concentration in a complex in vitro biofilm infection model using 19 F MRI: Persistence of an oxygen sink despite prolonged antibiotic therapy. Magn Reson Med 2019; 82:2248-2256. [PMID: 31373035 DOI: 10.1002/mrm.27888] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 01/29/2023]
Abstract
PURPOSE Oxygen availability is a critical determinant of microbial biofilm activity and antibiotic susceptibility. However, measuring oxygen gradients in these systems remains difficult, with the standard microelectrode approach being both invasive and limited to single-point measurement. The goal of the study was to develop a 19 F MRI approach for 2D oxygen mapping in biofilm systems and to visualize oxygen consumption behavior in real time during antibiotic therapy. METHODS Oxygen-sensing beads were created by encapsulating an emulsion of oxygen-sensing fluorocarbon into alginate gel. Escherichia coli biofilms were grown in and on the alginate matrix, which was contained inside a packed bed column subjected to nutrient flow, mimicking the complex porous structure of human wound tissue, and subjected to antibiotic challenge. RESULTS The linear relationship between 19 F spin-lattice relaxation rate R1 and local oxygen concentration permitted noninvasive spatial mapping of oxygen distribution in real time over the course of biofilm growth and subsequent antibiotic challenge. This technique was used to visualize persistence of microbial oxygen respiration during continuous gentamicin administration, providing a time series of complete spatial maps detailing the continued bacterial utilization of oxygen during prolonged chemotherapy in an in vitro biofilm model with complex spatial structure. CONCLUSIONS Antibiotic exposure temporarily causes oxygen consumption to enter a pseudosteady state wherein oxygen distribution becomes fixed; oxygen sink expansion resumes quickly after antibiotic clearance. This technique may provide valuable information for future investigations of biofilms by permitting the study of complex geometries (typical of in vivo biofilms) and facilitating noninvasive oxygen measurement.
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Affiliation(s)
- Jeffrey W Simkins
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
| | - Sarah L Codd
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, Montana
| | - Joseph D Seymour
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
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41
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Ashton NN, Allyn G, Porter ST, Haussener TJ, Sebahar PR, Looper RE, Williams DL. In vitro testing of a first-in-class tri-alkylnorspermidine-biaryl antibiotic in an anti-biofilm silicone coating. Acta Biomater 2019; 93:25-35. [PMID: 30769135 DOI: 10.1016/j.actbio.2019.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/22/2019] [Accepted: 02/09/2019] [Indexed: 01/02/2023]
Abstract
Biofilm-related infection is among the worst complication to prosthetic joint replacement procedures; once established on the implant surface, biofilms show strong recalcitrance to clinical antibiotic therapy, frequently requiring costly revision procedures and prolonged systemic antibiotics for their removal. A well-designed active release coating might assist host immunity in clearing bacterial contaminants within the narrow perioperative window and ultimately prevent microbial colonization of the joint prosthesis. A first-in-class compound (CZ-01127) was tested as the active release agent in a silicone (Si) coating using an in vitro dynamic flow model of surgical site contamination and compared with analogous coatings containing clinical gold-standard antibiotics vancomycin and gentamicin; the CZ-01127 coating outperformed both vancomycin and gentamicin coatings and was the only to decrease the methicillin-resistant Staphylococcus aureus (MRSA) inocula below detectable limits for the first 3 days. The antimicrobial activity of CZ-01127, and for comparison vancomycin and gentamicin, were characterized against both planktonic and biofilm MRSA using the minimum inhibitory concentration (MIC) assay, serial passages, and serial dilution tests against established biofilms grown with a CBR 90 CDC biofilm reactor. Despite a similar MIC (1 µg/ml) and behavior in a 25-day serial passage analysis, CZ-01127 displayed much greater bactericidal activity against established biofilms and was the only to decrease biofilm colony forming units (CFUs) below detectable limits at the highest concentration tested (500 µg/ml). Coating release profiles were characterized using ATR-FTIR and displayed burst release kinetics within the decisive period of the perioperative window suggesting the silicon carrier is broadly useful for screening antibiotic compound for local delivery applications. STATEMENT OF SIGNIFICANCE: With an aging population, an increasing number of people are undergoing total joint replacement procedures in which diseased joint tissues are replaced with permanent metallic implants. Some of these procedures are burdened by costly and debilitating infections. A promising approach to prevent infections is the use of an antimicrobial coating on the surface of the implant which releases antibiotics into the surgical site to prevent infection. In this study, we tested a new antibiotic compound formulated in a silicone coating. Data showed that this compound was more effective at killing pathogenic methicillin resistant Staphylococcus aureus (MRSA) bacteria than two clinical gold-standard antibiotics-vancomycin and gentamicin-and could be a promising agent for antimicrobial coating technologies.
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Affiliation(s)
- Nicholas N Ashton
- George E. Wahlen Department of Veterans Affairs, Salt Lake City, UT, United States; Department of Orthopaedics, University of Utah, Salt Lake City, UT, United States
| | - Gina Allyn
- George E. Wahlen Department of Veterans Affairs, Salt Lake City, UT, United States; Department of Orthopaedics, University of Utah, Salt Lake City, UT, United States
| | - Scott T Porter
- George E. Wahlen Department of Veterans Affairs, Salt Lake City, UT, United States; Department of Orthopaedics, University of Utah, Salt Lake City, UT, United States
| | - Travis J Haussener
- Curza Global, LLC, Salt Lake City, UT, United States; Synthetic and Medicinal Chemistry Core, University of Utah, Salt Lake City, UT, United States
| | - Paul R Sebahar
- Curza Global, LLC, Salt Lake City, UT, United States; Synthetic and Medicinal Chemistry Core, University of Utah, Salt Lake City, UT, United States
| | - Ryan E Looper
- Curza Global, LLC, Salt Lake City, UT, United States; Synthetic and Medicinal Chemistry Core, University of Utah, Salt Lake City, UT, United States; Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Dustin L Williams
- George E. Wahlen Department of Veterans Affairs, Salt Lake City, UT, United States; Department of Orthopaedics, University of Utah, Salt Lake City, UT, United States; Curza Global, LLC, Salt Lake City, UT, United States; Department of Pathology, University of Utah, Salt Lake City, UT, United States; Department of Bioengineering, University of Utah, Salt Lake City, UT, United States; Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
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Abstract
We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms.
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43
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Seviour T, Derlon N, Dueholm MS, Flemming HC, Girbal-Neuhauser E, Horn H, Kjelleberg S, van Loosdrecht MCM, Lotti T, Malpei MF, Nerenberg R, Neu TR, Paul E, Yu H, Lin Y. Extracellular polymeric substances of biofilms: Suffering from an identity crisis. WATER RESEARCH 2019; 151:1-7. [PMID: 30557778 DOI: 10.1016/j.watres.2018.11.020] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/02/2018] [Accepted: 11/10/2018] [Indexed: 06/09/2023]
Abstract
Microbial biofilms can be both cause and cure to a range of emerging societal problems including antimicrobial tolerance, water sanitation, water scarcity and pollution. The identities of extracellular polymeric substances (EPS) responsible for the establishment and function of biofilms are poorly understood. The lack of information on the chemical and physical identities of EPS limits the potential to rationally engineer biofilm processes, and impedes progress within the water and wastewater sector towards a circular economy and resource recovery. Here, a multidisciplinary roadmap for addressing this EPS identity crisis is proposed. This involves improved EPS extraction and characterization methodologies, cross-referencing between model biofilms and full-scale biofilm systems, and functional description of isolated EPS with in situ techniques (e.g. microscopy) coupled with genomics, proteomics and glycomics. The current extraction and spectrophotometric characterization methods, often based on the principle not to compromise the integrity of the microbial cells, should be critically assessed, and more comprehensive methods for recovery and characterization of EPS need to be developed.
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Affiliation(s)
- Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore.
| | - Nicolas Derlon
- EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600, Dübendorf, Switzerland
| | - Morten Simonsen Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Hans-Curt Flemming
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore; University of Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Essen, Germany
| | - Elisabeth Girbal-Neuhauser
- Laboratoire de Biotechnologies Agroalimentaire et Environmentale (LBAE), Universite Paul Sabatier, Toulouse, France
| | - Harald Horn
- Karlsruhe Institute of Technology (KIT), Engler-Bunte-Institut, Water Chemistry and Water Technology and DVGW Research Laboratories, Karlsruhe, Germany
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | | | - Tommaso Lotti
- Department of Civil and Environmental Engineering - DICEA, University of Florence, Florence, Italy
| | - M Francesca Malpei
- Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Milan, Italy
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, USA
| | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
| | - Etienne Paul
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Université de Toulouse, Toulouse, France
| | - Hanqing Yu
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Yuemei Lin
- Department of Biotechcnology, Delft University of Technology, Delft, the Netherlands.
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44
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Fuqua C, Filloux A, Ghigo JM, Visick KL. Biofilms 2018: A diversity of microbes and mechanisms. J Bacteriol 2019; 201:JB.00118-19. [PMID: 30782638 PMCID: PMC6707918 DOI: 10.1128/jb.00118-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The 8th ASM Conference on Biofilms was held in Washington D.C. on October 7-11, 2018. This very highly subscribed meeting represented a wide breadth of current research in biofilms, and included over 500 attendees, 12 sessions with 64 oral presentations, and four poster sessions with about 400 posters.
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Affiliation(s)
- Clay Fuqua
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, United Kingdom
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
| | - Karen L. Visick
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
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45
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Ren Z, Kim D, Paula AJ, Hwang G, Liu Y, Li J, Daniell H, Koo H. Dual-Targeting Approach Degrades Biofilm Matrix and Enhances Bacterial Killing. J Dent Res 2019; 98:322-330. [PMID: 30678538 DOI: 10.1177/0022034518818480] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Biofilm formation is a key virulence factor responsible for a wide range of infectious diseases, including dental caries. Cariogenic biofilms are structured microbial communities embedded in an extracellular matrix that affords bacterial adhesion-cohesion and drug tolerance, making them difficult to treat using conventional antimicrobial monotherapy. Here, we investigated a multitargeted approach combining exopolysaccharide (EPS) matrix-degrading glucanohydrolases with a clinically used essential oils-based antimicrobial to potentiate antibiofilm efficacy. Our data showed that dextranase and mutanase can synergistically break down the EPS glucan matrix in preformed cariogenic biofilms, markedly enhancing bacterial killing by the antimicrobial agent (3-log increase versus antimicrobial alone). Further analyses revealed that an EPS-degrading/antimicrobial (EDA) approach disassembles the matrix scaffold, exposing the bacterial cells for efficient killing while concurrently causing cellular dispersion and "physical collapse" of the bacterial clusters. Unexpectedly, we found that the EDA approach can also selectively target the EPS-producing cariogenic bacteria Streptococcus mutans with higher killing specificity (versus other species) within mixed biofilms, disrupting their accumulation and promoting dominance of commensal bacteria. Together, these results demonstrate a dual-targeting approach that can enhance antibiofilm efficacy and precision by dismantling the EPS matrix and its protective microenvironment, amplifying the killing of pathogenic bacteria within.
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Affiliation(s)
- Z Ren
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.,2 Biofilm Research Laboratories, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - D Kim
- 2 Biofilm Research Laboratories, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - A J Paula
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.,3 Solid-Biological Interface Group (SolBIN), Departamento de Física, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - G Hwang
- 2 Biofilm Research Laboratories, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Y Liu
- 2 Biofilm Research Laboratories, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - J Li
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China
| | - H Daniell
- 4 Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - H Koo
- 2 Biofilm Research Laboratories, Levy Center for Oral Health, Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
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46
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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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47
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Wu Y, Klapper I, Stewart PS. Hypoxia arising from concerted oxygen consumption by neutrophils and microorganisms in biofilms. Pathog Dis 2018; 76:4982780. [PMID: 29688319 DOI: 10.1093/femspd/fty043] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 04/20/2018] [Indexed: 11/14/2022] Open
Abstract
Infections associated with microbial biofilms are often found to involve hypoxic or anoxic conditions within the biofilm or its vicinity. To shed light on the phenomenon of local oxygen depletion, mathematical reaction-diffusion models were derived that integrated the two principal oxygen sinks, microbial respiration and neutrophil consumption. Three simple one-dimensional problems were analyzed approximating biofilm near an air interface as in a dermal wound or mucus layer, biofilm on an implanted medical device, or biofilm aggregates dispersed in mucus or tissue. In all three geometries considered, hypoxia at the biofilm-neutrophil interface or within the biofilm was predicted for a subset of plausible parameter values. The finding that oxygen concentration at the biofilm-neutrophil juncture can be diminished to hypoxic levels is biologically relevant because oxygen depletion will reduce neutrophil killing ability. The finding that hypoxia can readily establish in the interior of the biofilm is biologically relevant because this change will alter microbial metabolism and persistence.
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Affiliation(s)
- Yilin Wu
- Department of Mathematics, Temple University, Philadelphia, PA 19122, USA
| | - Isaac Klapper
- Department of Mathematics, Temple University, Philadelphia, PA 19122, USA
| | - Philip S Stewart
- Center for Biofilm Engineering and Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717-3980, USA
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48
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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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49
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An Overlooked but Effective Wound Care Methodology: Hydromechanical Therapy Revisited. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2018; 6:e1883. [PMID: 30324065 PMCID: PMC6181508 DOI: 10.1097/gox.0000000000001883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/13/2018] [Indexed: 11/28/2022]
Abstract
Chronic wounds are frequently difficult, expensive to treat, and pose a significant burden on both the patient’s quality of life and health care system. Their recalcitrance to treatment stems from multiple factors, particularly the presence of bacterial biofilms within the wound bed. However, a commonly overlooked modality in the field of wound care, pressurized irrigation, offers an inexpensive mechanical debridement force capable of dislodging these biofilms that contribute to delayed healing of chronic wounds. We present here a single clinical case of a difficult nonhealing wound that had previously failed 3 months of negative-pressure wound therapy, a much more expensive modality. This chronic plantar foot wound was treated with daily application of hydromechanical therapy using tap water at home. It achieved a stable granulation surface, and with a small skin graft, healing with no recurrence seen at 15-month follow-up. We speculate that a combination of tissue stimulation and disruption of the wound surface biofilm contribute to improved healing, supporting a reevaluation for the use of pressurized irrigation in the treatment of chronic wounds.
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50
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Towards standardized mechanical characterization of microbial biofilms: analysis and critical review. NPJ Biofilms Microbiomes 2018; 4:17. [PMID: 30131867 PMCID: PMC6102240 DOI: 10.1038/s41522-018-0062-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 02/05/2023] Open
Abstract
Developing reliable anti-biofilm strategies or efficient biofilm-based bioprocesses strongly depends on having a clear understanding of the mechanisms underlying biofilm development, and knowledge of the relevant mechanical parameters describing microbial biofilm behavior. Many varied mechanical testing methods are available to assess these parameters. The mechanical properties thus identified can then be used to compare protocols such as antibiotic screening. However, the lack of standardization in both mechanical testing and the associated identification methods for a given microbiological goal remains a blind spot in the biofilm community. The pursuit of standardization is problematic, as biofilms are living structures, i.e., both complex and dynamic. Here, we review the main available methods for characterizing the mechanical properties of biofilms through the lens of the relationship linking experimental testing to the identification of mechanical parameters. We propose guidelines for characterizing biofilms according to microbiological objectives that will help the reader choose an appropriate test and a relevant identification method for measuring any given mechanical parameter. The use of a common methodology for the mechanical characterization of biofilms will enable reliable analysis and comparison of microbiological protocols needed for improvement of engineering process and screening.
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