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Bajaj A, Abutoama M, Isaacs S, Abuleil MJ, Yaniv K, Kushmaro A, Modic M, Cvelbar U, Abdulhalim I. Biofilm growth monitoring using guided wave ultralong-range Surface Plasmon Resonance: A proof of concept. Biosens Bioelectron 2023; 228:115204. [PMID: 36913883 DOI: 10.1016/j.bios.2023.115204] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 03/01/2023] [Accepted: 03/05/2023] [Indexed: 03/15/2023]
Abstract
Unwelcomed biofilms are problematic in food industries, surgical devices, marine applications, and wastewater treatment plants, essentially everywhere where there is moisture. Very recently, label-free advanced sensors such as localized and extended surface plasmon resonance (SPR) have been explored as tools for monitoring biofilm formation. However, conventional noble metal SPR substrates suffer from low penetration depth (100-300 nm) into the dielectric medium above the surface, preventing the reliable detection of large entities of single or multi-layered cell assemblies like biofilms which can grow up to a few micrometers or more. In this study, we propose using a plasmonic insulator-metal-insulator (IMI) structure (SiO2-Ag-SiO2) with a higher penetration depth based on a diverging beam single wavelength format of Kretschmann configuration in a portable SPR device. An SPR line detection algorithm for locating the reflectance minimum of the device helps to view changes in refractive index and accumulation of the biofilm in real-time down to 10-7 RIU precision. The optimized IMI structure exhibits strong penetration dependence on wavelength and incidence angle. Within the plasmonic resonance, different angles penetrate different depths, showing a maximum near the critical angle. At the wavelength of 635 nm, a high penetration depth of more than 4 μm was obtained. Compared to a thin gold film substrate, for which the penetration depth is only ∼200 nm, the IMI substrate provides more reliable results. The average thickness of the biofilm after 24 h of growth was found to be between 6 and 7 μm with ∼63% live cell volume, as estimated from confocal microscopic images using an image processing tool. To explain this saturation thickness, a graded index biofilm structure is proposed in which the refractive index decreases with the distance from the interface. Furthermore, when plasma-assisted degeneration of biofilms was studied in a semi-real-time format, there was almost no effect on the IMI substrate compared to the gold substrate. The growth rate over the SiO2 surface was higher than on gold, possibly due to differences between surface charge effects. On the gold, the excited plasmon generates an oscillating cloud of electrons, while for the SiO2 case, this does not happen. This methodology can be utilized to detect and characterize biofilms with better signal reliability with respect to concentration and size dependence.
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Affiliation(s)
- Aabha Bajaj
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Mohammad Abutoama
- Department of Electro-optics and Photonics Engineering, ECE School, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Sivan Isaacs
- Department of Electro-optics and Photonics Engineering, ECE School, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Marwan J Abuleil
- Department of Electro-optics and Photonics Engineering, ECE School, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Karin Yaniv
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Ariel Kushmaro
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel; Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel; School of Sustainability and Climate Change, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Martina Modic
- Department of Gaseous Electronics (F6), Jožef Stefan Institute, Jamova cesta 39, SI-1000, Ljubljana, Slovenia
| | - Uroš Cvelbar
- Department of Gaseous Electronics (F6), Jožef Stefan Institute, Jamova cesta 39, SI-1000, Ljubljana, Slovenia
| | - Ibrahim Abdulhalim
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel; Department of Electro-optics and Photonics Engineering, ECE School, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel.
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Carrascosa C, Raheem D, Ramos F, Saraiva A, Raposo A. Microbial Biofilms in the Food Industry-A Comprehensive Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18042014. [PMID: 33669645 PMCID: PMC7922197 DOI: 10.3390/ijerph18042014] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/16/2022]
Abstract
Biofilms, present as microorganisms and surviving on surfaces, can increase food cross-contamination, leading to changes in the food industry’s cleaning and disinfection dynamics. Biofilm is an association of microorganisms that is irreversibly linked with a surface, contained in an extracellular polymeric substance matrix, which poses a formidable challenge for food industries. To avoid biofilms from forming, and to eliminate them from reversible attachment and irreversible stages, where attached microorganisms improve surface adhesion, a strong disinfectant is required to eliminate bacterial attachments. This review paper tackles biofilm problems from all perspectives, including biofilm-forming pathogens in the food industry, disinfectant resistance of biofilm, and identification methods. As biofilms are largely responsible for food spoilage and outbreaks, they are also considered responsible for damage to food processing equipment. Hence the need to gain good knowledge about all of the factors favouring their development or growth, such as the attachment surface, food matrix components, environmental conditions, the bacterial cells involved, and electrostatic charging of surfaces. Overall, this review study shows the real threat of biofilms in the food industry due to the resistance of disinfectants and the mechanisms developed for their survival, including the intercellular signalling system, the cyclic nucleotide second messenger, and biofilm-associated proteins.
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Affiliation(s)
- Conrado Carrascosa
- Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain;
- Correspondence: (C.C.); (A.R.)
| | - Dele Raheem
- Northern Institute for Environmental and Minority Law (NIEM), Arctic Centre, University of Lapland, 96101 Rovaniemi, Finland;
| | - Fernando Ramos
- Pharmacy Faculty, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal;
- REQUIMTE/LAQV, R. D. Manuel II, 55142 Apartado, Portugal
| | - Ariana Saraiva
- Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain;
| | - António Raposo
- CBIOS (Research Center for Biosciences and Health Technologies), Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal
- Correspondence: (C.C.); (A.R.)
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Liu T, Liu J, Liu J, Yang R, Lu X, He X, Shi W, Guo L. Interspecies Interactions Between Streptococcus Mutans and Streptococcus Agalactiae in vitro. Front Cell Infect Microbiol 2020; 10:344. [PMID: 32733820 PMCID: PMC7358462 DOI: 10.3389/fcimb.2020.00344] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/04/2020] [Indexed: 01/30/2023] Open
Abstract
Streptococcus mutans is an oral species closely associated with dental caries. As an early oral colonizer, S. mutans utilizes interspecies coaggregation to promote the colonization of subsequent species and affect polymicrobial pathogenesis. Previous studies have confirmed several adhering partner species of S. mutans, including Candida albicans and Fusobacterium nucleatum. In this study, we discovered new intergeneric co-adherence between S. mutans and the saliva isolate Streptococcus agalactiae (GBS-SI101). Research shows that GBS typically colonizes the human gastrointestinal and vaginal tracts. It is responsible for adverse pregnancy outcomes and life-threatening infections in neonates and immunocompromised people. Our results revealed that GtfB and GtfC of S. mutans, which contributed to extracellular polysaccharide synthesis, promoted coaggregation of S. mutans with GBS-SI101. In addition, oral streptococci, including Streptococcus sanguinis, Streptococcus gordonii and S. mutans, barely inhibited the growth of GBS-SI101. This study indicated that S. mutans could help GBS integrate into the Streptococcus-associated oral polymicrobial community and become a resident species in the oral cavity, increasing the risk of oral infections.
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Affiliation(s)
- Tingjun Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jia Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jianwei Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Ruiqi Yang
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xianjun Lu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xuesong He
- The Forsyth Institute, Cambridge, MA, United States
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Wenyuan Shi
- The Forsyth Institute, Cambridge, MA, United States
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Lihong Guo
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
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Mira A, Buetas E, Rosier B, Mazurel D, Villanueva-Castellote Á, Llena C, Ferrer MD. Development of an in vitro system to study oral biofilms in real time through impedance technology: validation and potential applications. J Oral Microbiol 2019; 11:1609838. [PMID: 31105900 PMCID: PMC6507917 DOI: 10.1080/20002297.2019.1609838] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/10/2019] [Accepted: 04/12/2019] [Indexed: 11/21/2022] Open
Abstract
Background and objectives: We have developed a standardized, easy-to-use in vitro model to study single- and multiple-species oral biofilms in real time through impedance technology, which elucidates the kinetics of biofilm formation in 96-well plates, without the requirement for any further manipulation. Design and Results: Using this system, biofilms of Streptococcus mutans appear to be sugar-dependent and highly resistant to amoxicilin, an antibiotic to which this oral pathogen is highly sensitive in a planktonic state. Saliva, tongue and dental plaque samples were also used as inocula to form multiple-species biofilms. DNA isolation and Illumina sequencing of the biofilms showed that the multi-species biofilms were formed by tens or hundreds of species, had a similar composition to the original inoculum, and included fastidious microorganisms which are important for oral health and disease. As an example of the potential applications of the model, we show that oral biofilms can be inhibited by amoxicilin, but in some cases they are induced by the antibiotic, suggesting the existence of responders and non-responders to a given antibiotic. Conclusions: We therefore propose the system as a valid in vitro model to study oral biofilm dynamics, including their susceptibility to antibiotics, antiseptics or anti-adhesive compounds.
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Affiliation(s)
- Alex Mira
- FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
| | - Elena Buetas
- FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
| | - Bob Rosier
- FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
| | - Danuta Mazurel
- FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
| | | | - Carmen Llena
- Departamento de Estomatologia, University of Valencia, Valencia, Spain
| | - Maria D Ferrer
- FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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6
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Azevedo AS, Almeida C, Pereira B, Madureira P, Wengel J, Azevedo NF. Detection and discrimination of biofilm populations using locked nucleic acid/2′-O-methyl-RNA fluorescence in situ hybridization (LNA/2′OMe-FISH). Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.04.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Neu TR, Lawrence JR. Investigation of microbial biofilm structure by laser scanning microscopy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 146:1-51. [PMID: 24840778 DOI: 10.1007/10_2014_272] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microbial bioaggregates and biofilms are hydrated three-dimensional structures of cells and extracellular polymeric substances (EPS). Microbial communities associated with interfaces and the samples thereof may come from natural, technical, and medical habitats. For imaging such complex microbial communities confocal laser scanning microscopy (CLSM) is the method of choice. CLSM allows flexible mounting and noninvasive three-dimensional sectioning of hydrated, living, as well as fixed samples. For this purpose a broad range of objective lenses is available having different working distance and resolution. By means of CLSM the signals detected may originate from reflection, autofluorescence, reporter genes/fluorescence proteins, fluorochromes binding to specific targets, or other probes conjugated with fluorochromes. Recorded datasets can be used not only for visualization but also for semiquantitative analysis. As a result CLSM represents a very useful tool for imaging of microbiological samples in combination with other analytical techniques.
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Affiliation(s)
- Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, 39114, Magdeburg, Germany,
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8
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Chlorhexidine substantivity on salivary flora and plaque-like biofilm: an in situ model. PLoS One 2013; 8:e83522. [PMID: 24386220 PMCID: PMC3873939 DOI: 10.1371/journal.pone.0083522] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 11/05/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To evaluate the in situ antibacterial activity of a mouthrinse with 0.2% Chlorhexidine (M-0.2% CHX) on undisturbed de novo plaque-like biofilm (PL-biofilm) and on salivary flora up to 7 hours after its application. METHODS A special acrylic appliance was designed, with 3 inserted glass disks on each buccal side, allowing for PL-biofilm growth. Fifteen healthy volunteers wore the appliance for 48 hours and then performed an M-0.2% CHX; disks were removed at 30 seconds and 1, 3, 5 and 7 hours after the mouth-rinsing. Applying a washout period, saliva samples were collected from each volunteer at 30 seconds and 1, 3, 5 and 7 hours after performing an M-0.2% CHX. The PL-biofilm and saliva samples were analysed by confocal laser scanning and epifluorescence microscopes, respectively. RESULTS At 30 seconds after M-0.2% CHX, the levels of viable bacteria detected in saliva were significantly lower than those observed in PL-biofilm. The difference in the percentage of live bacteria detected in saliva was significantly higher than that observed in PL-biofilm at 5 and 7 hours after M-0.2% CHX. CONCLUSION After a single mouthrinse of the 0.2% CHX formulation tested in the present study, the 2-day PL-biofilm presented a significantly higher resistance to this antiseptic in situ than that observed in salivary flora. However, this 0.2% CHX formulation showed a higher substantivity on PL-biofilm than on salivary flora at 5 and 7 hours after mouth-rinsing, which could be related to the slower growth rate of PL-biofilm and the possible reservoir function for antimicrobial agents associated with the undisturbed de novo PL-biofilm.
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Guo L, Hu W, He X, Lux R, McLean J, Shi W. investigating acid production by Streptococcus mutans with a surface-displayed pH-sensitive green fluorescent protein. PLoS One 2013; 8:e57182. [PMID: 23468929 PMCID: PMC3585301 DOI: 10.1371/journal.pone.0057182] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/18/2013] [Indexed: 12/31/2022] Open
Abstract
Acidogenicity and aciduricity are the main virulence factors of the cavity-causing bacterium Streptococcus mutans. Monitoring at the individual cell level the temporal and spatial distribution of acid produced by this important oral pathogen is central for our understanding of these key virulence factors especially when S. mutans resides in multi-species microbial communities. In this study, we explored the application of pH-sensitive green fluorescent proteins (pHluorins) to investigate these important features. Ecliptic pHluorin was functionally displayed on the cell surface of S. mutans as a fusion protein with SpaP. The resulting strain (O87) was used to monitor temporal and spatial pH changes in the microenvironment of S. mutans cells under both planktonic and biofilm conditions. Using strain O87, we revealed a rapid pH drop in the microenviroment of S. mutans microcolonies prior to the decrease in the macro-environment pH following sucrose fermentation. Meanwhile, a non-uniform pH distribution was observed within S. mutans biofilms, reflecting differences in microbial metabolic activity. Furthermore, strain O87 was successfully used to monitor the S. mutans acid production profiles within dual- and multispecies oral biofilms. Based on these findings, the ecliptic pHluorin allows us to investigate in vivo and in situ acid production and distribution by the cariogenic species S. mutans.
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Affiliation(s)
- Lihong Guo
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Wei Hu
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
- State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, Jinan, China
| | - Xuesong He
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Renate Lux
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jeff McLean
- J. Craig Venter Institute, San Diego, California, United States of America
| | - Wenyuan Shi
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
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Rapid probing of biological surfaces with a sparse-matrix peptide library. PLoS One 2011; 6:e23551. [PMID: 21858167 PMCID: PMC3156232 DOI: 10.1371/journal.pone.0023551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 07/20/2011] [Indexed: 02/02/2023] Open
Abstract
Finding unique peptides to target specific biological surfaces is crucial to basic research and technology development, though methods based on biological arrays or large libraries limit the speed and ease with which these necessary compounds can be found. We reasoned that because biological surfaces, such as cell surfaces, mineralized tissues, and various extracellular matrices have unique molecular compositions, they present unique physicochemical signatures to the surrounding medium which could be probed by peptides with appropriately corresponding physicochemical properties. To test this hypothesis, a naïve pilot library of 36 peptides, varying in their hydrophobicity and charge, was arranged in a two-dimensional matrix and screened against various biological surfaces. While the number of peptides in the matrix library was very small, we obtained “hits” against all biological surfaces probed. Sequence refinement of the “hits” led to peptides with markedly higher specificity and binding activity against screened biological surfaces. Genetic studies revealed that peptide binding to bacteria was mediated, at least in some cases, by specific cell-surface molecules, while examination of human tooth sections showed that this method can be used to derive peptides with highly specific binding to human tissue.
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11
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Schlapp G, Scavone P, Zunino P, Härtel S. Development of 3D architecture of uropathogenic Proteus mirabilis batch culture biofilms-A quantitative confocal microscopy approach. J Microbiol Methods 2011; 87:234-40. [PMID: 21864585 DOI: 10.1016/j.mimet.2011.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/25/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022]
Abstract
This work studies the development of the 3D architecture of batch culture P. mirabilis biofilms on the basis of morpho-topological descriptors calculated from confocal laser scanning microscopy (CLSM) stacks with image processing routines. A precise architectonical understanding of biofilm organization on a morpho-topological level is necessary to understand emergent interactions with the environment and the appearance of functionally different progeny swarmer cells. P. mirabilis biofilms were grown on glass coverslips for seven days on LB broth and subjected to in situ immunofluorescence. Confocal image stacks were deconvolved prior to segmentation of regions of interest (ROI) that identify individual bacteria and extracellular material, followed by 3D reconstruction and calculation of different morpho-topological key descriptors. Results showed that P. mirabilis biofilm formation followed a five stage process: (i) reversible adhesion to the surface characterized by slow growth, presence of elongated bacteria, and absence of extracellular material, (ii) irreversible bacterial adhesion concomitant to decreasing elongation, and the beginning of extracellular polymer production, (iii) accelerated bacterial growth concomitant to continuously decreasing elongation and halting of extracellular polymer production, (iv) maturation of biofilm defined by maximum bacterial density, volume, minimum elongation, maximum extracellular material, and highest compaction, and (v) decreased bacterial density and extracellular material through detachment and dispersion. Swarmer cells do not play a role in P. mirabilis biofilm formation under the applied conditions. Our approach sets the basis for future studies of 3D biofilm architecture using dynamic in vivo models and different environmental conditions that assess clinical impacts of P. mirabilis biofilm.
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Affiliation(s)
- G Schlapp
- Department of Microbiology, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, Montevideo, Uruguay
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Almeida C, Azevedo NF, Santos S, Keevil CW, Vieira MJ. Discriminating multi-species populations in biofilms with peptide nucleic acid fluorescence in situ hybridization (PNA FISH). PLoS One 2011; 6:e14786. [PMID: 21479268 PMCID: PMC3066202 DOI: 10.1371/journal.pone.0014786] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 10/11/2010] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Our current understanding of biofilms indicates that these structures are typically composed of many different microbial species. However, the lack of reliable techniques for the discrimination of each population has meant that studies focusing on multi-species biofilms are scarce and typically generate qualitative rather than quantitative data. METHODOLOGY/PRINCIPAL FINDINGS We employ peptide nucleic acid fluorescence in situ hybridization (PNA FISH) methods to quantify and visualize mixed biofilm populations. As a case study, we present the characterization of Salmonella enterica/Listeria monocytogenes/Escherichia coli single, dual and tri-species biofilms in seven different support materials. Ex-situ, we were able to monitor quantitatively the populations of ∼56 mixed species biofilms up to 48 h, regardless of the support material. In situ, a correct quantification remained more elusive, but a qualitative understanding of biofilm structure and composition is clearly possible by confocal laser scanning microscopy (CLSM) at least up to 192 h. Combining the data obtained from PNA FISH/CLSM with data from other established techniques and from calculated microbial parameters, we were able to develop a model for this tri-species biofilm. The higher growth rate and exopolymer production ability of E. coli probably led this microorganism to outcompete the other two [average cell numbers (cells/cm(2)) for 48 h biofilm: E. coli 2,1 × 10(8) (± 2,4 × 10(7)); L. monocytogenes 6,8 × 10(7) (± 9,4 × 10(6)); and S. enterica 1,4 × 10(6) (± 4,1 × 10(5))]. This overgrowth was confirmed by CSLM, with two well-defined layers being easily identified: the top one with E. coli, and the bottom one with mixed regions of L. monocytogenes and S. enterica. SIGNIFICANCE While PNA FISH has been described previously for the qualitative study of biofilm populations, the present investigation demonstrates that it can also be used for the accurate quantification and spatial distribution of species in polymicrobial communities. Thus, it facilitates the understanding of interspecies interactions and how these are affected by changes in the surrounding environment.
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Affiliation(s)
- Carina Almeida
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, Universidade do Minho, Campus de Gualta, Braga, Portugal
- Environmental Healthcare Unit, School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Nuno F. Azevedo
- Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Sílvio Santos
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, Universidade do Minho, Campus de Gualta, Braga, Portugal
| | - Charles W. Keevil
- Environmental Healthcare Unit, School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Maria J. Vieira
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, Universidade do Minho, Campus de Gualta, Braga, Portugal
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Pan PC, Harper S, Ricci-Nittel D, Lux R, Shi W. In-vitro evidence for efficacy of antimicrobial mouthrinses. J Dent 2010; 38 Suppl 1:S16-20. [PMID: 20621239 DOI: 10.1016/s0300-5712(10)70006-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE The objective of this study was to compare the antimicrobial activity of commercially available antiseptic mouthrinses against saliva-derived plaque biofilms in static and flow-through biofilm systems in vitro. METHODS Nine mouthrinses were tested in a recirculating flow-through biofilm model (RFTB) with viability assessment by ATP bioluminescence. In addition, five mouthrinses were evaluated in a batch chamber slide biofilm (BCSB) model, using live/dead staining and confocal laser scanning microscopy. RESULTS In the RFTB model, essential oil (EO) and chlorhexidine (CHX)-containing rinses showed equivalent antimicrobial activity and were more effective than a range of cetyl pyridinium chloride (CPC1) formulations. In the BCSB model, twice-daily mouthrinse exposure demonstrated that the EO rinse was significantly more effective than rinses containing amine and stannous fluorides (AFSF), a combination of CPC/CHX, and another CPC formulation (CPC2). EO showed biofilm kill comparable to the CHX rinse. CONCLUSIONS The present studies have shown that mouthrinses vary significantly in their capability to kill plaque biofilm bacteria in BCSB and RFTB models. The EO mouthrinse demonstrated superior antiplaque biofilm activity to AFSF, CPC/CHX, and CPC rinses and comparable activity to CHX. The methods tested may be of value for the in-vitro screening of antiseptic rinses with different modes of antimicrobial action.
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Affiliation(s)
- Pauline C Pan
- J&J Consumer & Personal Products Worldwide, Division of J&J Consumer Companies Inc, 185 Tabor Road, Morris Plains, NJ 07950, USA.
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Neu TR, Manz B, Volke F, Dynes JJ, Hitchcock AP, Lawrence JR. Advanced imaging techniques for assessment of structure, composition and function in biofilm systems. FEMS Microbiol Ecol 2010; 72:1-21. [PMID: 20180852 DOI: 10.1111/j.1574-6941.2010.00837.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Scientific imaging represents an important and accepted research tool for the analysis and understanding of complex natural systems. Apart from traditional microscopic techniques such as light and electron microscopy, new advanced techniques have been established including laser scanning microscopy (LSM), magnetic resonance imaging (MRI) and scanning transmission X-ray microscopy (STXM). These new techniques allow in situ analysis of the structure, composition, processes and dynamics of microbial communities. The three techniques open up quantitative analytical imaging possibilities that were, until a few years ago, impossible. The microscopic techniques represent powerful tools for examination of mixed environmental microbial communities usually encountered in the form of aggregates and films. As a consequence, LSM, MRI and STXM are being used in order to study complex microbial biofilm systems. This mini review provides a short outline of the more recent applications with the intention to stimulate new research and imaging approaches in microbiology.
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Affiliation(s)
- Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany.
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15
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Malic S, Hill KE, Hayes A, Percival SL, Thomas DW, Williams DW. Detection and identification of specific bacteria in wound biofilms using peptide nucleic acid fluorescent in situ hybridization (PNA FISH). MICROBIOLOGY-SGM 2009; 155:2603-2611. [PMID: 19477903 DOI: 10.1099/mic.0.028712-0] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biofilms provide a reservoir of potentially infectious micro-organisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic inflammatory conditions is increasingly being recognized. Particular research interest exists in the association of biofilms with wound infection and non-healing, i.e. chronic wounds. In this study, fluorescent in situ hybridization (FISH) was used in combination with confocal laser scanning microscopy (CLSM) to detect and characterize the spatial distribution of biofilm-forming bacteria which predominate within human chronic skin wounds (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Micrococcus sp.). In vitro biofilms were prepared using a constant-depth film fermenter and a reconstituted human epidermis model. In vivo biofilms were also studied using biopsy samples from non-infected chronic venous leg ulcers. The specificity of peptide nucleic acid (PNA) probes for the target organisms was confirmed using mixed preparations of planktonic bacteria and multiplex PNA probing. Identification and location of individual bacterial species within multi-species biofilms demonstrated that P. aeruginosa was predominant. CLSM revealed clustering of individual species within mixed-species biofilms. FISH analysis of archive chronic wound biopsy sections showed bacterial presence and allowed bacterial load to be determined. The application of this standardized procedure makes available an assay for identification of single- or multi-species bacterial populations in tissue biopsies. The technique provides a reliable tool to study bacterial biofilm formation and offers an approach to assess targeted biofilm disruption strategies in vivo.
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Affiliation(s)
- Sladjana Malic
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - Katja E Hill
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - Anthony Hayes
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3US, UK
| | - Steven L Percival
- School of Medicine, University of West Virginia, Morgantown, WV 26506, USA
| | - David W Thomas
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - David W Williams
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
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de Carvalho CCCR, da Fonseca MMR. Assessment of three-dimensional biofilm structure using an optical microscope. Biotechniques 2007; 42:616, 618-20. [PMID: 17515200 DOI: 10.2144/000112403] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A method allowing the evaluation of the structure and the calculation of the volume of a biofilm, using an optical microscope, is proposed based on the linear relation between the intensity of a pixel in biofilm images grabbed on the x-y plane and the corresponding number of cells in the z direction, which allows the calculation of the biofilm thickness. The method is intended to overcome the need for expensive microscopes to study biofilms.
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Affiliation(s)
- Carla C C R de Carvalho
- Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal.
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Chalmers NI, Palmer RJ, Du-Thumm L, Sullivan R, Shi W, Kolenbrander PE. Use of quantum dot luminescent probes to achieve single-cell resolution of human oral bacteria in biofilms. Appl Environ Microbiol 2006; 73:630-6. [PMID: 17114321 PMCID: PMC1796960 DOI: 10.1128/aem.02164-06] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Oral biofilms are multispecies communities, and in their nascent stages of development, numerous bacterial species engage in interspecies interactions. Better insight into the spatial relationship between different species and how species diversity increases over time can guide our understanding of the role of interspecies interactions in the development of the biofilms. Quantum dots (QD) are semiconductor nanocrystals and have emerged as a promising tool for labeling and detection of bacteria. We sought to apply QD-based primary immunofluorescence for labeling of bacterial cells with in vitro and in vivo biofilms and to compare this approach with the fluorophore-based primary immunofluorescence approach we have used previously. To investigate QD-based primary immunofluorescence as the means to detect distinct targets with single-cell resolution, we conjugated polyclonal and monoclonal antibodies to the QD surface. We also conducted simultaneous QD conjugate-based and fluorophore conjugate-based immunofluorescence and showed that these conjugates were complementary tools in immunofluorescence applications. Planktonic and biofilm cells were labeled effectively by considering two factors: the final nanomolar concentration of QD conjugate and the amount of antibody conjugated to the QD, which we define as the degree of labeling. These advances in the application of QD-based immunofluorescence for the study of biofilms in vitro and in vivo will help to define bacterial community architecture and to facilitate investigations of interactions between bacterial species in these communities.
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Affiliation(s)
- Natalia I Chalmers
- Department of Biomedical Sciences, University of Maryland Dental School, Baltimore, Maryland 21201, USA
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Abstract
Although genomics has classically focused on pure, easy-to-obtain samples, such as microbes that grow readily in culture or large animals and plants, these organisms represent only a fraction of the living or once-living organisms of interest. Many species are difficult to study in isolation because they fail to grow in laboratory culture, depend on other organisms for critical processes, or have become extinct. Methods that are based on DNA sequencing circumvent these obstacles, as DNA can be isolated directly from living or dead cells in various contexts. Such methods have led to the emergence of a new field, which is referred to as metagenomics.
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Affiliation(s)
- Susannah Green Tringe
- Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, California 94598, USA
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