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Park S, Kumar S, Maier CS, Kreth J, Koley D. Simultaneous Chemical Mapping of Live Biofilm Microenvironmental pH and Hydrogen Peroxide in Real Time with a Triple Scanning Electrochemical Microscopy Tip. Anal Chem 2023; 95:6332-6340. [PMID: 37018485 PMCID: PMC10485357 DOI: 10.1021/acs.analchem.2c05258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Dental plaque biofilm is a complex ecosystem. The distribution of microbial species in the biofilm is heavily influenced by local chemical interactions that result from diverse metabolic activities and the nature of the released molecules. As a relevant example, H2O2-producing bacteria can antagonize disease-associated bacteria, leading to the maintenance of a healthy oral microbiome. Herein, we report the development of a triple-sensor (redox, pH, and H2O2) scanning electrochemical microscopy (SECM) tip capable of simultaneously mapping the pH and H2O2 concentration produced by a dental plaque-derived multispecies biofilm grown on hydroxyapatite. The pH sensor of the triple SECM tip showed a near Nernstian slope of -71.1 ± 2 mV/pH (N = 3), whereas the H2O2 sensor showed a slope of -0.052 ± 0.002 nA/μM H2O2 at pH 7.2 and a detection limit of 1.0 ± 0.2 μM (N = 7). There is no significant difference in the sensitivities of H2O2 sensors at pH 6.2, 7.2, and 8.2 at 95% CI (N = 7). The pH and H2O2 sensors demonstrated excellent reversibility with response times of 3 and 5 s, respectively, along with reliable stability over 4 h at 37 °C. The sensors did not show any cross talk between pH and H2O2 concentration ([H2O2]) measurements, highlighting the accuracy and versatility of the SECM tip. Simultaneous chemical imaging of pH and [H2O2] across the biofilm revealed a clustered distribution of local H2O2 concentrations, ranging from 0 to 17 μM. Conversely, the local pH remained constant at 7.2. The relation of local chemical profiles and the distribution of bacterial species within the oral microbiome was experimentally investigated in the context of bacterial H2O2 antagonism. The benefit of clustered H2O2 production was that the total area of H2O2 produced by smaller clusters was 67% more than that of a single cluster with the same starting number of bacteria. Thus, this triple SECM tip can potentially be used to study local molecular mechanisms that result in dysbiosis of the oral microbiome.
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Affiliation(s)
- Suji Park
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Sriram Kumar
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Claudia S Maier
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon 97201, United States
| | - Dipankar Koley
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
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Structure-function characterization of Streptococcus intermedius surface antigen Pas. J Bacteriol 2021; 203:e0017521. [PMID: 34339301 DOI: 10.1128/jb.00175-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus intermedius, an oral commensal bacterium, is found at various sites including subgingival dental plaque, purulent infections, and in cystic fibrosis lungs. Oral streptococci utilize proteins on their surface to adhere to tissues and/or surfaces localizing the bacteria, which subsequently leads to the development of biofilms, colonization and infection. Among the 19 genomically annotated cell-wall attached surface proteins on S. intermedius, Pas is an adhesin that belongs to the Antigen I/II (AgI/II) family. Here we have structurally and functionally characterized Pas, particularly focusing on its microbial-host as well as microbial-microbial interactions. The crystal structures of VPas and C123Pas show high similarity with AgI/II of S. mutans. VPas hosts a conserved metal binding site, and likewise the C123Pas structure retains its conserved metal binding sites and isopeptide bonds within its three DEv-IgG domains. Pas interacts with nanomolar affinity to lung alveolar glycoprotein 340 (Gp340), its scavenger receptor cysteine rich domains (SRCRs) and with fibrinogen. Both Candida albicans and Pseudomonas aeruginosa, the opportunistic pathogens that cohabitate with S. intermedius in the lungs of CFTR patients were studied in dual-species biofilm studies. The Pas deficient mutant (Δpas) displayed significant reduction in dual biofilm formation with C. albicans. In similar studies with P. aeruginosa, Pas did not mediate the biofilm formation with either the acute isolate (PAO1), or the chronic isolate (FRD1). However, the Sortase A deficient mutant (ΔsrtA) displayed reduced biofilm formation with both C. albicans and P. aeruginosa FRD1. Taken together, our findings highlight the role of Pas in both microbial-host and interkingdom interactions and expose its potential role in disease outcomes. Importance Streptococcus intermedius, an oral commensal bacterium, has been clinically observed in subgingival dental plaque, purulent infections, and in cystic fibrosis lungs. In this study, we have (a) determined the crystal structure of the V- and C-regions of Pas; (b) shown that its surface protein Pas adheres to fibrinogen, which could potentially ferry the microbe through the blood stream from the oral cavity; (c) characterized Pas's high affinity adherence to lung alveolar protein Gp340 that could fixate the microbe on lung epithelial cells; and (d) most importantly shown that these surface proteins on the oral commensal S. intermedius enhances biofilms of known pathogens Candida albicans and Pseudomonas aeruginosa.
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Monteiro DR, de Souza Batista VE, Caldeirão ACM, Jacinto RDC, Pessan JP. Oral prosthetic microbiology: aspects related to the oral microbiome, surface properties, and strategies for controlling biofilms. BIOFOULING 2021; 37:353-371. [PMID: 34139899 DOI: 10.1080/08927014.2021.1912741] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/21/2021] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
The oral cavity is an environment that allows for the development of complex ecosystems; the placement of prosthetic devices as a consequence of partial or total tooth loss may alter the diversity of microbial communities. Biofilms on the surface of materials used in dental prostheses can promote important changes in the mechanic and aesthetic properties of the material itself and may cause local and systemic diseases for the prosthetic wearer. This review presents the main features of the oral microbiome associated with complete or partial dentures and dental implants. The main diseases associated with microbial colonization of prosthetic surfaces, factors that may affect biofilm formation on prosthetic materials, as well as novel alternative therapies aiming to reduce biofilm formation and/or to eradicate biofilms formed on these materials are also explored.
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Affiliation(s)
- Douglas Roberto Monteiro
- Graduate Program in Dentistry, University of Western São Paulo (UNOESTE), Presidente Prudente, São Paulo, Brazil
- School of Dentistry, Araçatuba, Department of Preventive and Restorative Dentistry, São Paulo State University (Unesp), Araçatuba, São Paulo, Brazil
| | | | | | - Rogério de Castilho Jacinto
- School of Dentistry, Araçatuba, Department of Preventive and Restorative Dentistry, São Paulo State University (Unesp), Araçatuba, São Paulo, Brazil
| | - Juliano Pelim Pessan
- School of Dentistry, Araçatuba, Department of Preventive and Restorative Dentistry, São Paulo State University (Unesp), Araçatuba, São Paulo, Brazil
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Shokeen B, Park J, Duong E, Rambhia S, Paul M, Weinberg A, Shi W, Lux R. Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation. Microorganisms 2020; 8:E70. [PMID: 31906541 PMCID: PMC7023056 DOI: 10.3390/microorganisms8010070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/25/2019] [Accepted: 12/31/2019] [Indexed: 11/17/2022] Open
Abstract
: RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacterium nucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcus gordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S. gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.
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Affiliation(s)
- Bhumika Shokeen
- Section of Periodontics, Division of Constitutive & Regenerative Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Jane Park
- Section of Periodontics, Division of Constitutive & Regenerative Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Emily Duong
- Section of Periodontics, Division of Constitutive & Regenerative Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Sonam Rambhia
- Section of Periodontics, Division of Constitutive & Regenerative Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Manash Paul
- David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Aaron Weinberg
- Department of Biological Sciences, Case Western Reserve University, Cleveland, OH 44106-4905, USA
| | - Wenyuan Shi
- The Forsyth Institute, Cambridge, MA 02142, USA
| | - Renate Lux
- Section of Periodontics, Division of Constitutive & Regenerative Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA
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Alotaibi M, Moran G, Grufferty B, Renvert S, Polyzois I. The effect of a decontamination protocol on contaminated titanium dental implant surfaces with different surface topography in edentulous patients. Acta Odontol Scand 2019; 77:66-75. [PMID: 30264636 DOI: 10.1080/00016357.2018.1504986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Objectives: To investigate if it is possible to achieve complete decontamination of dental implant surfaces with different surface characteristics.Materials and methods: Twelve implant pieces with an Osseotite® surface and 12 implant pieces with a Ti-Unite® surface were attached on to the complete lower dentures of six patients and were allowed to accumulate plaque for 30 days. When retrieved, the implant decontamination protocol used, involved both mechanical (PeriBrush™) and chemical (3% H2O2) decontamination. The number of colony forming units per millilitre was determined and the dominant micro-organisms in selected samples was identified by 16s rRNA gene amplicon sequencing. The effect of the titanium brush on the implant surface was examined by SEM.Results: Complete decontamination was achieved in five out of 24 implants (four Osseotite® and one Ti-Unite®). The mean CFU/ml detected after decontamination were 464.48 for Osseotite® and 729.09 for Ti-Unite® implants. On the surface of the implants in which complete decontamination was not achieved, all of the predominant bacteria identified were streptococci except for one which was identified as micrococcus. SEM images revealed that the surface features of the decontaminated implants were not significantly altered.Conclusions: Mechanical decontamination using a titanium brush supplemented with chemical treatment for one minute (3% H2O2) can achieve complete decontamination of implant surfaces in edentulous patients.
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Affiliation(s)
- Mohammad Alotaibi
- Department of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, Trinity College, Dublin, Ireland
| | - Gary Moran
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital Trinity College, Dublin, Ireland
| | - Brendan Grufferty
- Department of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, Trinity College, Dublin, Ireland
| | - Stefan Renvert
- Department of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, Trinity College, Dublin, Ireland
- Department of Health Sciences, Kristianstad University, Kristianstad, Sweden
- Blekinge Institute of Technology, Karlskrona, Sweden
| | - Ioannis Polyzois
- Department of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, Trinity College, Dublin, Ireland
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Ferreira Ribeiro C, Cogo-Müller K, Franco GC, Silva-Concílio LR, Sampaio Campos M, de Mello Rode S, Claro Neves AC. Initial oral biofilm formation on titanium implants with different surface treatments: An in vivo study. Arch Oral Biol 2016; 69:33-9. [PMID: 27232358 DOI: 10.1016/j.archoralbio.2016.05.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 03/30/2016] [Accepted: 05/08/2016] [Indexed: 01/14/2023]
Abstract
OBJECTIVE The aim of this study was to examine in vivo the initial bacterial adhesion on titanium implants with different surface treatments. DESIGN Ten subjects wore oral splints containing machined pure titanium disks (Ti-M), acid-etched titanium (Ti-AE) and anodized and laser irradiated disks (Ti-AL) for 24h. After this period, disks were removed from the splints and adherent bacteria were quantified by an enzymatic assay to assess total viable bacteria and by Real Time PCR to evaluate total bacteria and Streptococcus oralis levels. Additionally, the initial adherent microorganisms were visualized by scanning electron microscopy (SEM). Titanium surface morphology was verified using SEM, and roughness was evaluated by profilometer analysis. RESULTS Regarding titanium surface roughness, Ti-AL (1.423±0.397) showed significantly higher Ra values than did Ti-M (0.771±0.182) and Ti-AE (0.735±0.196) (p<0.05, ANOVA - Tahame). Ti-AE and Ti-AL presented roughened micro-structure surfaces characterized by open pores, whereas Ti-M showed long grooves alternating with planed areas. Comparing the Ti-M, Ti-AE and Ti-AL groups for viable bacteria (MTT assay), total bacteria and S. oralis quantification (qPCR), no significant differences were observed among these three groups (p>0.05, ANOVA - Tahame). SEM images showed similar bacterial adhesion on the three titanium surfaces, predominantly characterized by cocci and several bacilli, indicating an initial colonization of the oral biofilm. CONCLUSION In conclusion, roughness and microtopography did not stimulate initial biofilm formation on titanium surfaces with different surface treatments.
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Affiliation(s)
- Cyntia Ferreira Ribeiro
- Department of Prosthodontics, Dentistry School, University of Taubaté Rua: Expedicionário Ernesto Pereira, 110 Centro, Taubaté, SP 12020-330, Brazil
| | - Karina Cogo-Müller
- Faculty of Pharmaceutical Sciences, University of Campinas (UNICAMP), Rua Sérgio Buarque de Holanda, 250, CB-II - sala E06 - 2° Piso, 13083-859, Campinas, SP, Brazil.
| | - Gilson Cesar Franco
- Department of General Biology, Area of Physiology and Pathophysiology, State University of Ponta Grossa Av. General Carlos Cavalcanti, 4748 Uvaranas, Ponta Grossa, PR 84030-900, Brazil
| | - Laís Regiane Silva-Concílio
- Department of Prosthodontics, Dentistry School, University of Taubaté Rua: Expedicionário Ernesto Pereira, 110 Centro, Taubaté, SP 12020-330, Brazil
| | - Márcia Sampaio Campos
- Department of Cariology, Restorative Sciences and Endodontics, School of Dentistry, University of Michigan, 1011N University Ave, Ann Arbor 48109, MI, USA
| | - Sigmar de Mello Rode
- Department of Dental Materials and Prosthodontics, Science and Technology Institute, Paulista State University "Júlio de Mesquita Filho" (UNESP), Av. Eng. Francisco José Longo, 777 Jardim São Dimas, São José dos Campos, SP 12245-000, Brazil
| | - Ana Christina Claro Neves
- Department of Prosthodontics, Dentistry School, University of Taubaté Rua: Expedicionário Ernesto Pereira, 110 Centro, Taubaté, SP 12020-330, Brazil
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Wu T, Cen L, Kaplan C, Zhou X, Lux R, Shi W, He X. Cellular Components Mediating Coadherence of Candida albicans and Fusobacterium nucleatum. J Dent Res 2015; 94:1432-8. [PMID: 26152186 DOI: 10.1177/0022034515593706] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Candida albicans is an opportunistic fungal pathogen found as part of the normal oral flora. It can be coisolated with Fusobacterium nucleatum, an opportunistic bacterial pathogen, from oral disease sites, such as those involved in refractory periodontitis and pulp necrosis. The physical coadherence between these 2 clinically important microbes has been well documented and suggested to play a role in facilitating their oral colonization and colocalization and contributing to polymicrobial pathogenesis. Previous studies indicated that the physical interaction between C. albicans and F. nucleatum was mediated by the carbohydrate components on the surface of C. albicans and the protein components on the Fusobaterium cell surface. However, the identities of the components involved still remain elusive. This study was aimed at identifying the genetic determinants involved in coaggregation between the 2 species. By screening a C. albicans SN152 mutant library and a panel of F. nucleatum 23726 outer membrane protein mutants, we identified FLO9, which encodes a putative adhesin-like cell wall mannoprotein of C. albicans and radD, an arginine-inhibitable adhesin-encoding gene in F. nucleatum that is involved in interspecies coadherence. Consistent with these findings, we demonstrated that the strong coaggregation between wild-type F. nucleatum 23726 and C. albicans SN152 in an in vitro assay could be greatly inhibited by arginine and mannose. Our study also suggested a complex multifaceted mechanism underlying physical interaction between C. albicans and F. nucleatum and for the first time revealed the identity of major genetic components involved in mediating the coaggregation. These observations provide useful knowledge for developing new targeted treatments for disrupting interactions between these 2 clinically relevant pathogens.
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Affiliation(s)
- T Wu
- School of Dentistry, University of California, Los Angeles, CA, USA
| | - L Cen
- School of Dentistry, University of California, Los Angeles, CA, USA
| | - C Kaplan
- C3 Jian, Inc., Marina del Rey, CA, USA
| | - X Zhou
- West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - R Lux
- School of Dentistry, University of California, Los Angeles, CA, USA
| | - W Shi
- School of Dentistry, University of California, Los Angeles, CA, USA
| | - X He
- School of Dentistry, University of California, Los Angeles, CA, USA
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Precision-guided antimicrobial peptide as a targeted modulator of human microbial ecology. Proc Natl Acad Sci U S A 2015; 112:7569-74. [PMID: 26034276 DOI: 10.1073/pnas.1506207112] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
One major challenge to studying human microbiome and its associated diseases is the lack of effective tools to achieve targeted modulation of individual species and study its ecological function within multispecies communities. Here, we show that C16G2, a specifically targeted antimicrobial peptide, was able to selectively kill cariogenic pathogen Streptococcus mutans with high efficacy within a human saliva-derived in vitro oral multispecies community. Importantly, a significant shift in the overall microbial structure of the C16G2-treated community was revealed after a 24-h recovery period: several bacterial species with metabolic dependency or physical interactions with S. mutans suffered drastic reduction in their abundance, whereas S. mutans' natural competitors, including health-associated Streptococci, became dominant. This study demonstrates the use of targeted antimicrobials to modulate the microbiome structure allowing insights into the key community role of specific bacterial species and also indicates the therapeutic potential of C16G2 to achieve a healthy oral microbiome.
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Sarkar J, McHardy IH, Simanian EJ, Shi W, Lux R. Transcriptional responses of Treponema denticola to other oral bacterial species. PLoS One 2014; 9:e88361. [PMID: 24505483 PMCID: PMC3914990 DOI: 10.1371/journal.pone.0088361] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/06/2014] [Indexed: 12/16/2022] Open
Abstract
The classic organization by Socransky and coworkers categorized the oral bacteria of the subgingival plaque into different complexes. Treponema denticola, Porphyromonas gingivalis and Tannerella forsythia are grouped into the red complex that is highly correlated with periodontal disease. Socransky's work closely associates red with orange complex species such as Fusobacterium nucleatum and Prevotella intermedia but not with members of the other complexes. While the relationship between species contained by these complexes is in part supported by their ability to physically attach to each other, the physiological consequences of these interactions and associations are less clear. In this study, we employed T. denticola as a model organism to analyze contact-dependent responses to interactions with species belonging to the same complex (P. gingivalis and T. forsythia), the closely associated orange complex (using F. nucleatum and P. intermedia as representatives) and the unconnected yellow complex (using Streptococcus sanguinis and S. gordonii as representatives). RNA was extracted from T. denticola alone as well as after pairwise co-incubation for 5 hrs with representatives of the different complexes, and the respective gene expression profiles were determined using microarrays. Numerous genes related to motility, metabolism, transport, outer membrane and hypothetical proteins were differentially regulated in T. denticola in the presence of the tested partner species. Further analysis revealed a significant overlap in the affected genes and we identified a general response to the presence of other species, those specific to two of the three complexes as well as individual complexes. Most interestingly, many predicted major antigens (e.g. flagella, Msp, CTLP) were suppressed in responses that included red complex species indicating that the presence of the most closely associated species induces immune-evasive strategies. In summary, the data presented here provide an in-depth understanding of the transcriptional responses triggered by contact-dependent interactions between microorganisms inhabiting the periodontal pocket.
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Affiliation(s)
- Juni Sarkar
- School of Dentistry, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Ian H. McHardy
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Emil J. Simanian
- School of Dentistry, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Wenyuan Shi
- School of Dentistry, University of California, Los Angeles, Los Angeles, California, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, 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
- * E-mail:
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McLean RJC, Kakirde KS. Enhancing metagenomics investigations of microbial interactions with biofilm technology. Int J Mol Sci 2013; 14:22246-57. [PMID: 24284397 PMCID: PMC3856063 DOI: 10.3390/ijms141122246] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 11/16/2022] Open
Abstract
Investigations of microbial ecology and diversity have been greatly enhanced by the application of culture-independent techniques. One such approach, metagenomics, involves sample collections from soil, water, and other environments. Extracted nucleic acids from bulk environmental samples are sequenced and analyzed, which allows microbial interactions to be inferred on the basis of bioinformatics calculations. In most environments, microbial interactions occur predominately in surface-adherent, biofilm communities. In this review, we address metagenomics sampling and biofilm biology, and propose an experimental strategy whereby the resolving power of metagenomics can be enhanced by incorporating a biofilm-enrichment step during sample acquisition.
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Affiliation(s)
- Robert J C McLean
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
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Al-Ahmad A, Wiedmann-Al-Ahmad M, Fackler A, Follo M, Hellwig E, Bächle M, Hannig C, Han JS, Wolkewitz M, Kohal R. In vivo study of the initial bacterial adhesion on different implant materials. Arch Oral Biol 2013; 58:1139-47. [PMID: 23694907 DOI: 10.1016/j.archoralbio.2013.04.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/13/2013] [Accepted: 04/22/2013] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Biofilm formation on implant materials plays a major role in the aetiology of periimplantitis. The aim of this study was to examine in vivo the initial bacterial adhesion on six different implant materials. METHODS The implant materials Ti-m, TiUnite®, ZiUnite®, ATZ-m, ATZ-s, TZP-A-m were tested using bovine enamel slabs as controls. All materials, fixed on splint systems, were examined after 30 min and 120 min of oral exposure. DAPI staining was used for quantitative analysis of the initially adherent microorganisms. Initial adherent microorganisms were visualised by fluorescence In situ-hybridisation (FISH) and quantified by confocal laser scanning microscopy (CLSM). The targets of the oligonucleotide probes were Eubacteria, Veillonella spp., Fusobacterium nucleatum, Actinomyces naeslundii and Streptococcus spp. RESULTS DAPI analysis showed that increasing the time of oral exposure resulted in an increasing amount of initial adherent bacteria. The highest level of colonisation was on ZiUnite®, with the lowest occurring on the bovine enamel, followed by Ti-m. This early colonisation correlated significantly with the surface roughnesses of the materials. FISH and CLSM showed no significant differences relating to total bacterial composition. However, Streptococcus spp. was shown to be the main colonisers on each of the investigated materials. CONCLUSION it could be shown that within an oral exposure time of 30 min and 120 min, despite the salivary acquired pellicle initial biofilm formation is mainly influenced directly or indirect by the material surface topography. Highly polished surfaces should minimise the risk of biofilm formation, plaque accumulation and possibly periimplantitis.
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Affiliation(s)
- A Al-Ahmad
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Hugstetter Strasse 55, Freiburg, Germany.
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Lebeaux D, Chauhan A, Rendueles O, Beloin C. From in vitro to in vivo Models of Bacterial Biofilm-Related Infections. Pathogens 2013; 2:288-356. [PMID: 25437038 PMCID: PMC4235718 DOI: 10.3390/pathogens2020288] [Citation(s) in RCA: 300] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 05/01/2013] [Accepted: 05/08/2013] [Indexed: 12/13/2022] Open
Abstract
The influence of microorganisms growing as sessile communities in a large number of human infections has been extensively studied and recognized for 30–40 years, therefore warranting intense scientific and medical research. Nonetheless, mimicking the biofilm-life style of bacteria and biofilm-related infections has been an arduous task. Models used to study biofilms range from simple in vitro to complex in vivo models of tissues or device-related infections. These different models have progressively contributed to the current knowledge of biofilm physiology within the host context. While far from a complete understanding of the multiple elements controlling the dynamic interactions between the host and biofilms, we are nowadays witnessing the emergence of promising preventive or curative strategies to fight biofilm-related infections. This review undertakes a comprehensive analysis of the literature from a historic perspective commenting on the contribution of the different models and discussing future venues and new approaches that can be merged with more traditional techniques in order to model biofilm-infections and efficiently fight them.
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Affiliation(s)
- David Lebeaux
- Institut Pasteur, Unité de Génétique des Biofilms, 25 rue du Dr. Roux, 75724 Paris cedex 15, France.
| | - Ashwini Chauhan
- Institut Pasteur, Unité de Génétique des Biofilms, 25 rue du Dr. Roux, 75724 Paris cedex 15, France.
| | - Olaya Rendueles
- Institut Pasteur, Unité de Génétique des Biofilms, 25 rue du Dr. Roux, 75724 Paris cedex 15, France.
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, 25 rue du Dr. Roux, 75724 Paris cedex 15, France.
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Sandrin TR, Dowd SE, Herman DC, Maier RM. Aquatic Environments. Environ Microbiol 2009. [DOI: 10.1016/b978-0-12-370519-8.00006-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Kuramitsu HK, He X, Lux R, Anderson MH, Shi W. Interspecies interactions within oral microbial communities. Microbiol Mol Biol Rev 2007; 71:653-70. [PMID: 18063722 PMCID: PMC2168648 DOI: 10.1128/mmbr.00024-07] [Citation(s) in RCA: 373] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
While reductionism has greatly advanced microbiology in the past 400 years, assembly of smaller pieces just could not explain the whole! Modern microbiologists are learning "system thinking" and "holism." Such an approach is changing our understanding of microbial physiology and our ability to diagnose/treat microbial infections. This review uses oral microbial communities as a focal point to describe this new trend. With the common name "dental plaque," oral microbial communities are some of the most complex microbial floras in the human body, consisting of more than 700 different bacterial species. For a very long time, oral microbiologists endeavored to use reductionism to identify the key genes or key pathogens responsible for oral microbial pathogenesis. The limitations of reductionism forced scientists to begin adopting new strategies using emerging concepts such as interspecies interaction, microbial community, biofilms, polymicrobial disease, etc. These new research directions indicate that the whole is much more than the simple sum of its parts, since the interactions between different parts resulted in many new physiological functions which cannot be observed with individual components. This review describes some of these interesting interspecies-interaction scenarios.
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Affiliation(s)
- Howard K Kuramitsu
- Department of Oral Boiology, School of Dental Medicine, State University of New York, Buffalo, New York, USA
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17
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Abstract
INTRODUCTION Numerous biofilm models have been described for the study of bacteria associated with the supragingival plaque. However, there are fewer models available for the study of subgingival plaque. The purpose of this study was to develop and validate a model that closely mimicked the composition of the subgingival flora. METHODS The model was developed as follows: calcium hydroxyapatite disks were coated overnight with 10% sterile saliva, placed in flat-bottomed tissue culture plates containing trypticase-soy broth, directly inoculated with a small aliquot of dispersed subgingival plaque, incubated anaerobically, and transferred to fresh medium at 48-h intervals until climax (steady-state) biofilms were formed ( approximately 10 days). RESULTS The model, based on samples from eight periodontitis patients and eight healthy subjects, yielded a multi-species, heterogeneous biofilm, consisting of both gram-positive and gram-negative species, and comprising 15-20 cultivable species associated with the subgingival flora. The species present and their proportions were reflective of the initial cultivable subgingival flora. Comparisons of the initial plaque samples from healthy subjects and the mature biofilms showed 81% similarity in species and 70% similarity in the proportions present. Biofilms formed from samples obtained from periodontally diseased subjects were 69% similar in species and 57% similar in the proportions present. CONCLUSIONS The biofilm model described here closely reproduces the composition of the cultivable subgingival plaque both in the species present and in their relative proportions. Differences existed between biofilms grown from diseased and non-diseased sites with the former being characterized by the presence of periodontal pathogens at microbially significant levels.
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Affiliation(s)
- C Walker
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, USA.
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18
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Al-Ahmad A, Wunder A, Auschill TM, Follo M, Braun G, Hellwig E, Arweiler NB. The in vivo dynamics of Streptococcus spp., Actinomyces naeslundii, Fusobacterium nucleatum and Veillonella spp. in dental plaque biofilm as analysed by five-colour multiplex fluorescence in situ hybridization. J Med Microbiol 2007; 56:681-687. [PMID: 17446294 DOI: 10.1099/jmm.0.47094-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The formation and composition of dental plaque biofilm in vivo are important factors which influence the development of gingivitis, caries and periodontitis. Studying dental plaque biofilm in in vitro models can cause an oversimplification of the real conditions in the oral cavity. In this study, bovine enamel slabs were fixed in an individual acrylic appliance in situ to quantify dental plaque formation and composition using multiplex fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy. Each of the five oligonucleotide probes used for FISH was specific for either eubacteria or one of four frequently isolated bacterial constituents belonging to early and late colonizers of tooth surfaces. The thickness of formed biofilm increased from 14.9+/-5.0 microm after 1 day to 49.3+/-11.6 microm after 7 days. Streptococcus spp. were predominant in 1-day-old dental plaque and decreased significantly after 7 days (P=0.0061). Compared to the first day, Fusobacterium nucleatum decreased after 2 days and increased significantly after 7 days (P=0.0006). The decreases of Actinomyces naeslundii content on day 2 and day 7 were significant (P=0.0028). Changes in Veillonella spp. were not significant during the study period (P >0.05). The results showed that an in vivo observation period of 7 days was required to detect significant changes in Streptococcus spp. and F. nucleatum. The multiplex FISH used is suitable for analysing the dynamics of four important bacterial constituents in the oral biofilm in epidemiological studies.
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Affiliation(s)
- Ali Al-Ahmad
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany
| | - Axel Wunder
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany
| | | | - Marie Follo
- Department of Hematology and Oncology, Core Facility, Albert-Ludwigs-University, Freiburg, Germany
| | - Gabriele Braun
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany
| | - Elmar Hellwig
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany
| | - Nicole Birgit Arweiler
- Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany
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19
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Sheng J, Nguyen PTM, Baldeck JD, Olsson J, Marquis RE. Antimicrobial actions of benzimidazoles against the oral anaerobes Fusobacterium nucleatum and Prevotella intermedia. Arch Oral Biol 2006; 51:1015-23. [PMID: 16806047 DOI: 10.1016/j.archoralbio.2006.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 05/03/2006] [Accepted: 05/08/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND/OBJECTIVE Benzimidazoles are widely used as proton-pump inhibitors to control stomach hyperacidity and have been found also to have antimicrobial actions against Helicobacter pylori and oral streptococci. Our primary aim was to determine if they are active also against oral anaerobes associated with gingivitis. Our major focus was on catabolism because it leads to production of inflammatory metabolites such as butyrate and ammonia. The benzimidazoles are effective in the protonated form at acid pH values and cause irreversible inhibition of enzymes associated with formation of drug-target disulfide bonds. METHODS Fusobacterium nucleatum ATCC 25586 and Prevotella intermedia ATCC 25611 were grown anaerobically in suspension cultures, harvested, washed and exposed to the benzimidazole lansoprazole at pH values of 4 or 5 before being washed and used for standard assays to detect inhibition of catabolic functions, uptake of the agent and lethality. RESULTS Lansoprazole was found to be a bacteriostatic, multi-target antimicrobial against F. nucleatum under anaerobic conditions inhibitory for amino acid fermentation and also for glycolysis of glucose or fructose. ID(50) values for fermentation of amino acids and dipeptides by F. nucleatum ranged from 0.05 mM for lysine to 0.25 mM for serine. Fructose catabolism was highly sensitive with an ID(50) value of 0.03 mM apparently related to high sensitivity of the phosphoenolpyruvate:fructose phosphotransferase system, while the ID(50) for glucose catabolism by intact cells was some 0.07 mM. Fermentation of aspartate or aspartylaspartate by P. intermedia was found to be lansoprazole-sensitive with ID(50) values of about 0.18 and 0.20 mM, respectively. CONCLUSION Catabolism of amino acids, dipeptides and sugars by oral anaerobes associated with gingivitis are sensitive to the inhibitory actions of lansoprazole. Thus, catabolic pathways are potential targets for use of benzimidazoles against bacteria involved in gingivitis.
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Affiliation(s)
- Jiangyun Sheng
- Department of Microbiology and Immunology and Center for Oral Biology, The University of Rochester Medical Center, Rochester, NY 14642-8672, USA
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20
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Affiliation(s)
- Mary E Davey
- Department of Molecular Genetics, The Forsyth Institute, Boston, Massachusetts, USA
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21
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Pozhitkov A, Chernov B, Yershov G, Noble PA. Evaluation of gel-pad oligonucleotide microarray technology by using artificial neural networks. Appl Environ Microbiol 2006; 71:8663-76. [PMID: 16332861 PMCID: PMC1317365 DOI: 10.1128/aem.71.12.8663-8676.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Past studies have suggested that thermal dissociation analysis of nucleic acids hybridized to DNA microarrays would improve discrimination among duplex types by scanning through a broad range of stringency conditions. To more fully constrain the utility of this approach using a previously described gel-pad microarray format, artificial neural networks (NNs) were trained to recognize noisy or low-quality data, as might derive from nonspecific fluorescence, poor hybridization, or compromised data collection. The NNs were trained to classify dissociation profiles (melts) into groups based on selected characteristics (e.g., initial signal intensity, area under the curve) using a data set of 21,044 profiles derived from 186 probes hybridized to a study set of RNA extracted from 32 microbes common to the human oral cavity. Three melt profile groups were identified: one group consisted mostly of ideal melt profiles; another group consisted mostly of poor melt profiles; and, the remainder were difficult to classify. Screening of melting profiles of perfect-match hybrids revealed inconsistencies in the form of melting profiles even for identical probes on the same microarray hybridized to same target rRNA. Approximately 18% of perfect-match duplex types were correctly classified as poor. Experimental variability and deviation from ideal melt behavior were shown to be attributable primarily to a method of local background subtraction that was very sensitive to displacement of the grid frames used for image capture (both determined by the image analysis system) and duplexes with low binding constants. Additional results showed that long RNA fragments limit the discriminating power among duplex types.
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Affiliation(s)
- Alex Pozhitkov
- Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA
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22
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Smoot LM, Smoot JC, Smidt H, Noble PA, Könneke M, McMurry ZA, Stahl DA. DNA microarrays as salivary diagnostic tools for characterizing the oral cavity's microbial community. Adv Dent Res 2005; 18:6-11. [PMID: 15998937 DOI: 10.1177/154407370501800103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- L M Smoot
- Civil and Environmental Engineering, 302 More Hall, Box 352700, University of Washington, Seattle, WA 98195-2700, USA
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23
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Wirthlin MR, Chen PK, Hoover CI. A laboratory model biofilm fermenter: design and initial trial on a single species biofilm. J Periodontol 2005; 76:1443-9. [PMID: 16171430 DOI: 10.1902/jop.2005.76.9.1443] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The minimum inhibitory concentration (MIC) does not provide information on the efficacy of antimicrobial agents against infections involving biofilms, which are many times more resistant than planktonic forms of bacteria. This report is on the design and initial trial of a device for growing standard biofilms and testing antimicrobial agents. METHODS We constructed a durable, autoclaveable laboratory model biofilm fermenter (LMBF) that holds hydroxyapatite discs 300 microm below a surface onto which an artificial saliva medium drips at a rate comparable to human salivary flow. Inoculated with Streptococcus sanguinis, the device formed biofilms that were swept with a Teflon wiper under aerobic conditions. Five-day-old biofilm-coated discs were aseptically removed and placed in 3 ml of sterile saline, 0.12% chlorhexidine gluconate, or 0.1% phosphate-buffered chlorine dioxide mouthwash for 1 minute. The discs and test agent were immediately diluted with saline to 10 ml, vortexed for 30 seconds, serially diluted, plated on blood agar, and incubated anaerobically 2 days. Bacterial counts were done, and the MIC of each mouthwash was determined. RESULTS In tests with sterile water and sterile medium, the device maintained a closed system. After inoculation with S. sanguinis, a steady state was reached at day 5. Chlorhexidine at stock concentration achieved about a 2 log10 reduction (P = 0.002), but never achieved complete killing. Chlorine dioxide had no significant effect. The MIC against planktonic S. sanguinis was 112.8 microg/ml for chlorhexidine and 9.0 microg/ml for chlorine dioxide. CONCLUSIONS The LMBF generates and maintains a single-species oral model biofilm to a steady state and enables in vitro tests of disinfectant mouthwashes in simulated clinical use. It should be usable for more advanced tests of multiple species biofilms.
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Affiliation(s)
- M Robert Wirthlin
- Department of Orofacial Sciences, University of California--San Francisco, San Francisco, CA 94143-0762, USA
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24
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Schweickert B, Moter A, Lefmann M, Göbel UB. Let them fly or light them up: matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry and fluorescence in situ hybridization (FISH). APMIS 2005; 112:856-85. [PMID: 15638841 DOI: 10.1111/j.1600-0463.2004.apm11211-1210.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review focuses on clinical bacteriology and by and large does not cover the detection of fungi, viruses or parasites. It discusses two completely different but complementary approaches that may either supplement or replace classic culture-based bacteriology. The latter view may appear provocative in the light of the actual market penetration of molecular genetic testing in clinical bacteriology. Despite its elegance, high specificity and sensitivity, molecular genetic diagnostics has not yet reached the majority of clinical laboratories. The reasons for this are manifold: Many microbiologists and medical technologists are more familiar with classical microbiological methods than with molecular biology techniques. Culture-based methods still represent the work horse of everyday routine. The number of available FDA-approved molecular genetic tests is limited and external quality control is still under development. Finally, it appears difficult to incorporate genetic testing in the routine laboratory setting due to the limited number of samples received or the lack of appropriate resources. However, financial and time constraints, particularly in hospitals as a consequence of budget cuts and reduced length of stay, lead to a demand for significantly shorter turnaround times that cannot be met by culture-dependent diagnosis. As a consequence, smaller laboratories that do not have the technical and personal equipment required for molecular genetic amplification techniques may adopt alternative methods such as fluorescence in situ hybridization (FISH) that combines easy-to-perform molecular hybridization with microscopy, a technique familiar to every microbiologist. FISH is hence one of the technologies presented here. For large hospital or reference laboratories with a high sample volume requiring massive parallel high-throughput testing we discuss matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) of nucleic acids, a technology that has evolved from the post-genome sequencing era, for high-throughput sequence variation analysis (1, 2).
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Affiliation(s)
- Birgitta Schweickert
- Institut für Mikrobiologie und Hygiene, Charité, Universitätsmedizin Berlin, Germany
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25
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Foster JS, Palmer RJ, Kolenbrander PE. Human oral cavity as a model for the study of genome-genome interactions. THE BIOLOGICAL BULLETIN 2003; 204:200-204. [PMID: 12700154 DOI: 10.2307/1543559] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The enormous diversity of culturable bacteria within the oral microbial community coupled with experimental accessibility renders the human oral cavity a valuable model to investigate genome-genome interactions. The complex interactions of oral bacteria result in the formation of biofilms on the surfaces of the oral cavity. One mechanism thought to be important in biofilm formation is the coaggregation of bacterial partners. In this paper, we examine the role of coaggregation in oral biofilms and develop protocols to elucidate the spatial organization of bacterial species retained within oral biofilms. To explore these issues, we have employed two experimental systems: the saliva-coated flowcell and the retrievable enamel chip. From flowcell studies, we have determined that coaggregation can greatly influence the ability of an oral bacterial species to grow and be retained within the developing biofilm. To examine the spatial architecture of oral biofilms, fluorescent in situ hybridization protocols were developed that successfully target specific members of the oral microbial community. Together, these approaches provide insight into the development of oral biofilms and expand our understanding of genome-genome interactions.
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Affiliation(s)
- Jamie S Foster
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Building 30, Room 310, 30 Convent Drive MSC 4350, Bethesda, Maryland 20892-4350, USA
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26
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Kolenbrander PE, Andersen RN, Blehert DS, Egland PG, Foster JS, Palmer RJ. Communication among oral bacteria. Microbiol Mol Biol Rev 2002; 66:486-505, table of contents. [PMID: 12209001 PMCID: PMC120797 DOI: 10.1128/mmbr.66.3.486-505.2002] [Citation(s) in RCA: 606] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities.
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Affiliation(s)
- Paul E Kolenbrander
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4350, USA.
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27
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Rogers JD, Palmer RJ, Kolenbrander PE, Scannapieco FA. Role of Streptococcus gordonii amylase-binding protein A in adhesion to hydroxyapatite, starch metabolism, and biofilm formation. Infect Immun 2001; 69:7046-56. [PMID: 11598080 PMCID: PMC100085 DOI: 10.1128/iai.69.11.7046-7056.2001] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interactions between bacteria and salivary components are thought to be important in the establishment and ecology of the oral microflora. alpha-Amylase, the predominant salivary enzyme in humans, binds to Streptococcus gordonii, a primary colonizer of the tooth. Previous studies have implicated this interaction in adhesion of the bacteria to salivary pellicles, catabolism of dietary starches, and biofilm formation. Amylase binding is mediated at least in part by the amylase-binding protein A (AbpA). To study the function of this protein, an erythromycin resistance determinant [erm(AM)] was inserted within the abpA gene of S. gordonii strains Challis and FAS4 by allelic exchange, resulting in abpA mutant strains Challis-E1 and FAS4-E1. Comparison of the wild-type and mutant strains did not reveal any significant differences in colony morphology, biochemical metabolic profiles, growth in complex or defined media, surface hydrophobicity, or coaggregation properties. Scatchard analysis of adhesion isotherms demonstrated that the wild-type strains adhered better to human parotid-saliva- and amylase-coated hydroxyapatite than did the AbpA mutants. In contrast, the mutant strains bound to whole-saliva-coated hydroxyapatite to a greater extent than did the wild-type strains. While the wild-type strains preincubated with purified salivary amylase grew well in defined medium with potato starch as the sole carbohydrate source, the AbpA mutants did not grow under the same conditions even after preincubation with amylase. In addition, the wild-type strain produced large microcolonies in a flow cell biofilm model, while the abpA mutant strains grew much more poorly and produced relatively small microcolonies. Taken together, these results suggest that AbpA of S. gordonii functions as an adhesin to amylase-coated hydroxyapatite, in salivary-amylase-mediated catabolism of dietary starches and in human saliva-supported biofilm formation by S. gordonii.
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Affiliation(s)
- J D Rogers
- Department of Oral Biology, School of Dental Medicine, The State University of New York, Buffalo, New York 14214, USA
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28
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Palmer RJ, Kazmerzak K, Hansen MC, Kolenbrander PE. Mutualism versus independence: strategies of mixed-species oral biofilms in vitro using saliva as the sole nutrient source. Infect Immun 2001; 69:5794-804. [PMID: 11500457 PMCID: PMC98697 DOI: 10.1128/iai.69.9.5794-5804.2001] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During initial dental plaque formation, the ability of a species to grow when others cannot would be advantageous, and enhanced growth through interspecies and intergeneric cooperation could be critical. These characteristics were investigated in three coaggregating early colonizers of the tooth surface (Streptococcus gordonii DL1, Streptococcus oralis 34, and Actinomyces naeslundii T14V). Area coverage and cell cluster size measurements showed that attachment of A. naeslundii and of S. gordonii to glass flowcells was enhanced by a salivary conditioning film, whereas attachment of S. oralis was hindered. Growth experiments using saliva as the sole carbon and nitrogen source showed that A. naeslundii was unable to grow either in planktonic culture or as a biofilm, whereas S. gordonii grew under both conditions. S. oralis grew planktonically, but to a much lower maximum cell density than did S. gordonii; S. oralis did not grow reproducibly as a biofilm. Thus, only S. gordonii possessed all traits advantageous for growth as a solitary and independent resident of the tooth. Two-species biofilm experiments analyzed by laser confocal microscopy showed that neither S. oralis nor A. naeslundii grew when coaggregated pairwise with S. gordonii. However, both S. oralis and A. naeslundii showed luxuriant, interdigitated growth when paired together in coaggregated microcolonies. Thus, the S. oralis-A. naeslundii pair formed a mutualistic relationship, potentially contact dependent, that allows each to grow where neither could survive alone. S. gordonii, in contrast, neither was hindered by nor benefited from the presence of either of the other strains. The formation of mutually beneficial interactions within the developing biofilm may be essential for certain initial colonizers to be retained during early plaque development, whereas other initial colonizers may be unaffected by neighboring cells on the substratum.
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Affiliation(s)
- R J Palmer
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
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29
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Abstract
Oral microbial-plaque communities are biofilms composed of numerous genetically distinct types of bacteria that live in close juxtaposition on host surfaces. These bacteria communicate through physical interactions called coaggregation and coadhesion, as well as other physiological and metabolic interactions. Streptococci and actinomyces are the major initial colonizers of the tooth surface, and the interactions between them and their substrata help establish the early biofilm community. Fusobacteria play a central role as physical bridges that mediate coaggregation of cells and as physiological bridges that promote anaerobic microenvironments which protect coaggregating strict anaerobes in an aerobic atmosphere. New technologies for investigating bacterial populations with 16S rDNA probes have uncovered previously uncultured bacteria and have offered an approach to in situ examination of the spatial arrangement of the participant cells in oral-plaque biofilms. Flow cells with saliva-coated surfaces are particularly useful for studies of biofilm formation and observation. The predicted sequential nature of colonization of the tooth surface by members of different genera can be investigated by using these new technologies and imaging the cells in situ with confocal scanning laser microscopy. Members of at least seven genera now can be subjected to genetic studies owing to the discovery of gene-transfer systems in these genera. Identification of contact-inducible genes in streptococci offers an avenue to explore bacterial responses to their environment and leads the way toward understanding communication among inhabitants of a multispecies biofilm.
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Affiliation(s)
- P E Kolenbrander
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
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30
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Abstract
Biofilms are complex communities of microorganisms attached to surfaces or associated with interfaces. Despite the focus of modern microbiology research on pure culture, planktonic (free-swimming) bacteria, it is now widely recognized that most bacteria found in natural, clinical, and industrial settings persist in association with surfaces. Furthermore, these microbial communities are often composed of multiple species that interact with each other and their environment. The determination of biofilm architecture, particularly the spatial arrangement of microcolonies (clusters of cells) relative to one another, has profound implications for the function of these complex communities. Numerous new experimental approaches and methodologies have been developed in order to explore metabolic interactions, phylogenetic groupings, and competition among members of the biofilm. To complement this broad view of biofilm ecology, individual organisms have been studied using molecular genetics in order to identify the genes required for biofilm development and to dissect the regulatory pathways that control the plankton-to-biofilm transition. These molecular genetic studies have led to the emergence of the concept of biofilm formation as a novel system for the study of bacterial development. The recent explosion in the field of biofilm research has led to exciting progress in the development of new technologies for studying these communities, advanced our understanding of the ecological significance of surface-attached bacteria, and provided new insights into the molecular genetic basis of biofilm development.
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Affiliation(s)
- M E Davey
- Department of Microbiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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31
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Aspiras MB, Kazmerzak KM, Kolenbrander PE, McNab R, Hardegen N, Jenkinson HF. Expression of green fluorescent protein in Streptococcus gordonii DL1 and its use as a species-specific marker in coadhesion with Streptococcus oralis 34 in saliva-conditioned biofilms in vitro. Appl Environ Microbiol 2000; 66:4074-83. [PMID: 10966431 PMCID: PMC92261 DOI: 10.1128/aem.66.9.4074-4083.2000] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus gordonii is one of the predominant streptococci in the biofilm ecology of the oral cavity. It interacts with other bacteria through receptor-adhesin complexes formed between cognate molecules on the surfaces of the partner cells. To study the spatial organization of S. gordonii DL1 in oral biofilms, we used green fluorescent protein (GFP) as a species-specific marker to identify S. gordonii in a two-species in vitro oral biofilm flowcell system. To drive expression of gfp, we isolated and characterized an endogenous S. gordonii promoter, PhppA, which is situated upstream of the chromosomal hppA gene encoding an oligopeptide-binding lipoprotein. A chromosomal chloramphenicol acetyltransferase (cat) gene fusion with PhppA was constructed and used to demonstrate that PhppA was highly active throughout the growth of bacteria in batch culture. A promoterless 0.8-kb gfp ('gfp) cassette was PCR amplified from pBJ169 and subcloned to replace the cat cassette downstream of the S. gordonii-derived PhppA in pMH109-HPP, generating pMA1. Subsequently, the PhppA-'gfp cassette was PCR amplified from pMA1 and subcloned into pDL277 and pVA838 to generate the Escherichia coli-S. gordonii shuttle vectors pMA2 and pMA3, respectively. Each vector was transformed into S. gordonii DL1 aerobically to ensure GFP expression. Flow cytometric analyses of aerobically grown transformant cultures were performed over a 24-h period, and results showed that GFP could be successfully expressed in S. gordonii DL1 from PhppA and that S. gordonii DL1 transformed with the PhppA-'gfp fusion plasmid stably maintained the fluorescent phenotype. Fluorescent S. gordonii DL1 transformants were used to elucidate the spatial arrangement of S. gordonii DL1 alone in biofilms or with the coadhesion partner Streptococcus oralis 34 in two-species biofilms in a saliva-conditioned in vitro flowcell system. These results show for the first time that GFP expression in oral streptococci can be used as a species-specific marker in model oral biofilms.
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Affiliation(s)
- M B Aspiras
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
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32
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Hansen MC, Palmer RJ, White DC. Flowcell culture of Porphyromonas gingivalis biofilms under anaerobic conditions. J Microbiol Methods 2000; 40:233-9. [PMID: 10802140 DOI: 10.1016/s0167-7012(00)00126-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have developed an anaerobic biofilm culture system. The system is inexpensive, simple to use and, unlike an anaerobic glovebox, requires no dedicated space. As a test of the system, Porphyromonas gingivalis was cultured under low oxygen (1-2 ppm) and under anaerobic conditions (</=0.1 ppm O(2)). In the presence of small amounts of oxygen, the organism attached and formed an initial biofilm over the course of 4 h, but the biofilm was unable to maintain its growth and had lost biomass after 18 h. Also, ambiguous results were obtained when the biofilm was stained with a viability stain. Under anaerobic conditions, the biofilm was able to continue growth - biomass was greater after 18 h than after 4 h, and the anaerobic biofilm had a less ambiguous staining pattern than did the low-O(2)-grown biofilm.
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Affiliation(s)
- M C Hansen
- Department of Microbiology, Technical University of Denmark, DK-2800, Lyngby, Denmark
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