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Haugsten HR, Kristoffersen AK, Haug TM, Søland TM, Øvstebø R, Aass HCD, Enersen M, Galtung HK. Isolation, characterization, and fibroblast uptake of bacterial extracellular vesicles from Porphyromonas gingivalis strains. Microbiologyopen 2023; 12:e1388. [PMID: 37877660 PMCID: PMC10579780 DOI: 10.1002/mbo3.1388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/26/2023] Open
Abstract
Periodontitis is an inflammatory condition caused by bacteria and represents a serious health problem worldwide as the inflammation damages the supporting tissues of the teeth and may predispose to systemic diseases. Porphyromonas gingivalis is considered a keystone periodontal pathogen that releases bacterial extracellular vesicles (bEVs) containing virulence factors, such as gingipains, that may contribute to the pathogenesis of periodontitis. This study aimed to isolate and characterize bEVs from three strains of P. gingivalis, investigate putative bEV uptake into human oral fibroblasts, and determine the gingipain activity of the bEVs. bEVs from three bacterial strains, ATCC 33277, A7A1-28, and W83, were isolated through ultrafiltration and size-exclusion chromatography. Vesicle size distribution was measured by nano-tracking analysis (NTA). Transmission electron microscopy was used for bEV visualization. Flow cytometry was used to detect bEVs and gingipain activity was measured with an enzyme assay using a substrate specific for arg-gingipain. The uptake of bEVs into oral fibroblasts was visualized using confocal microscopy. NTA showed bEV concentrations from 108 to 1011 particles/mL and bEV diameters from 42 to 356 nm. TEM pictures demonstrated vesicle-like structures. bEV-gingipains were detected both by flow cytometry and enzyme assay. Fibroblasts incubated with bEVs labeled with fluorescent dye displayed intracellular localization consistent with bEV internalization. In conclusion, bEVs from P. gingivalis were successfully isolated and characterized, and their uptake into human oral fibroblasts was documented. The bEVs displayed active gingipains demonstrating their origin from P. gingivalis and the potential role of bEVs in periodontitis.
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Affiliation(s)
- Helene R. Haugsten
- Institute of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
| | | | - Trude M. Haug
- Institute of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
| | - Tine M. Søland
- Institute of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
- Department of PathologyOslo University HospitalOsloNorway
| | - Reidun Øvstebø
- The Blood Cell Research Group, Department of Medical BiochemistryOslo University HospitalUllevålNorway
| | - Hans C. D. Aass
- The Blood Cell Research Group, Department of Medical BiochemistryOslo University HospitalUllevålNorway
| | - Morten Enersen
- Institute of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
| | - Hilde K. Galtung
- Institute of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
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2
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Miller DP, Scott DA. Inherently and Conditionally Essential Protein Catabolism Genes of Porphyromonas gingivalis. Trends Microbiol 2020; 29:54-64. [PMID: 33071035 DOI: 10.1016/j.tim.2020.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/01/2020] [Accepted: 09/02/2020] [Indexed: 02/06/2023]
Abstract
Proteases are critical virulence determinants of Porphyromonas gingivalis, an emerging Alzheimer's disease, cancer, and arthritis pathogen and established agent of periodontitis. Transposon sequencing has been employed to define the core essential genome of this bacterium and genes conditionally essential in multiple environments - abscess formation; epithelial colonization; and cigarette smoke toxin exposure; as well as to elucidate genes required for iron acquisition and a functional type 9 secretion system. Validated and predicted protein catabolism genes identified include a combination of established virulence factors and a larger set of seemingly more mundane proteolytic genes. The functions and relevance of genes that share essentiality in multiple disease-relevant conditions are examined. These common stress-related genes may represent particularly attractive therapeutic targets for the control of P. gingivalis infections.
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Affiliation(s)
- Daniel P Miller
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - David A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY, USA.
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3
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Radhakrishnan P, Anbalagan R, Barani R, Mani M, Seshadri KG, Srikanth P. Sequencing of Porphyromonas gingivalis from saliva in patients with periodontitis and type 2 diabetes mellitus. Indian J Med Microbiol 2019; 37:54-59. [PMID: 31424011 DOI: 10.4103/ijmm.ijmm_18_409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background Porphyromonas gingivalis is a major periodontal pathogen. Saliva is the most easy, non-invasive microbiological sample for detection of periodontal pathogens. Aim and Objectives A prospective study on 37 diabetic patients was grouped into well-controlled diabetes with/without periodontitis and uncontrolled diabetic with periodontitis. PCR and sequencing of P. gingivalis was performed in saliva samples. Materials and Methods DNA was extracted from saliva using Triton X-100 and 16s rRNA gene (404 bp) was amplified by polymerase chain reaction. DNA sequencing was performed for two samples. Results P. gingivalis was detected in 27.03% (n = 10), of which 30% (n = 9) were diabetic with periodontal disease and 14.3% (n = 1) were diabetic without periodontal disease. The percentage of poor oral hygiene was 50% and 20% in uncontrolled and controlled glycaemic patients, respectively. DNA sequencing of two samples showed 100% identity with the sequences in the GenBank database (Gen Bank accession no: KX640913-KX640914). Conclusion Type 2 diabetes mellitus and periodontitis are interlinked. Early detection of P. gingivalis and appropriate treatment with doxycycline will also assist in controlling the glycaemic status.
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Affiliation(s)
- Preethi Radhakrishnan
- Department of Microbiology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Rubini Anbalagan
- Department of Microbiology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Ramya Barani
- Department of Microbiology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Monika Mani
- Department of Microbiology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Krishna G Seshadri
- Department of Endocrinology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Padma Srikanth
- Department of Microbiology, Diabetes and Metabolism, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
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Khachatryan L, Kraakman MEM, Bernards AT, Laros JFJ. BacTag - a pipeline for fast and accurate gene and allele typing in bacterial sequencing data based on database preprocessing. BMC Genomics 2019; 20:338. [PMID: 31060512 PMCID: PMC6501397 DOI: 10.1186/s12864-019-5723-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 04/22/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Bacteria carry a wide array of genes, some of which have multiple alleles. These different alleles are often responsible for distinct types of virulence and can determine the classification at the subspecies levels (e.g., housekeeping genes for Multi Locus Sequence Typing, MLST). Therefore, it is important to rapidly detect not only the gene of interest, but also the relevant allele. Current sequencing-based methods are limited to mapping reads to each of the known allele reference, which is a time-consuming procedure. RESULTS To address this limitation, we developed BacTag - a pipeline that rapidly and accurately detects which genes are present in a sequencing dataset and reports the allele of each of the identified genes. We exploit the fact that different alleles of the same gene have a high similarity. Instead of mapping the reads to each of the allele reference sequences, we preprocess the database prior to the analysis, which makes the subsequent gene and allele identification efficient. During the preprocessing, we determine a representative reference sequence for each gene and store the differences between all alleles and this chosen reference. Throughout the analysis we estimate whether the gene is present in the sequencing data by mapping the reads to this reference sequence; if the gene is found, we compare the variants to those in the preprocessed database. This allows to detect which specific allele is present in the sequencing data. Our pipeline was successfully tested on artificial WGS E. coli, S. pseudintermedius, P. gingivalis, M. bovis, Borrelia spp. and Streptomyces spp. data and real WGS E. coli and K. pneumoniae data in order to report alleles of MLST house-keeping genes. CONCLUSIONS We developed a new pipeline for fast and accurate gene and allele recognition based on database preprocessing and parallel computing and performed better or comparable to the current popular tools. We believe that our approach can be useful for a wide range of projects, including bacterial subspecies classification, clinical diagnostics of bacterial infections, and epidemiological studies.
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Affiliation(s)
- Lusine Khachatryan
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Margriet E M Kraakman
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Alexandra T Bernards
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeroen F J Laros
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.,GenomeScan, Leiden, The Netherlands
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Acuña-Amador L, Primot A, Cadieu E, Roulet A, Barloy-Hubler F. Genomic repeats, misassembly and reannotation: a case study with long-read resequencing of Porphyromonas gingivalis reference strains. BMC Genomics 2018; 19:54. [PMID: 29338683 PMCID: PMC5771137 DOI: 10.1186/s12864-017-4429-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/29/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Without knowledge of their genomic sequences, it is impossible to make functional models of the bacteria that make up human and animal microbiota. Unfortunately, the vast majority of publicly available genomes are only working drafts, an incompleteness that causes numerous problems and constitutes a major obstacle to genotypic and phenotypic interpretation. In this work, we began with an example from the class Bacteroidia in the phylum Bacteroidetes, which is preponderant among human orodigestive microbiota. We successfully identify the genetic loci responsible for assembly breaks and misassemblies and demonstrate the importance and usefulness of long-read sequencing and curated reannotation. RESULTS We showed that the fragmentation in Bacteroidia draft genomes assembled from massively parallel sequencing linearly correlates with genomic repeats of the same or greater size than the reads. We also demonstrated that some of these repeats, especially the long ones, correspond to misassembled loci in three reference Porphyromonas gingivalis genomes marked as circularized (thus complete or finished). We prove that even at modest coverage (30X), long-read resequencing together with PCR contiguity verification (rrn operons and an integrative and conjugative element or ICE) can be used to identify and correct the wrongly combined or assembled regions. Finally, although time-consuming and labor-intensive, consistent manual biocuration of three P. gingivalis strains allowed us to compare and correct the existing genomic annotations, resulting in a more accurate interpretation of the genomic differences among these strains. CONCLUSIONS In this study, we demonstrate the usefulness and importance of long-read sequencing in verifying published genomes (even when complete) and generating assemblies for new bacterial strains/species with high genomic plasticity. We also show that when combined with biological validation processes and diligent biocurated annotation, this strategy helps reduce the propagation of errors in shared databases, thus limiting false conclusions based on incomplete or misleading information.
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Affiliation(s)
- Luis Acuña-Amador
- Institut de Génétique et Développement de Rennes, CNRS, UMR6290, Université de Rennes 1, Rennes, France.,Laboratorio de Investigación en Bacteriología Anaerobia, Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Aline Primot
- Institut de Génétique et Développement de Rennes, CNRS, UMR6290, Université de Rennes 1, Rennes, France
| | - Edouard Cadieu
- Institut de Génétique et Développement de Rennes, CNRS, UMR6290, Université de Rennes 1, Rennes, France
| | - Alain Roulet
- GenoToul Genome & Transcriptome (GeT-PlaGe), INRA, US1426, Castanet-Tolosan, France
| | - Frédérique Barloy-Hubler
- Institut de Génétique et Développement de Rennes, CNRS, UMR6290, Université de Rennes 1, Rennes, France.
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Teixeira SRL, D'Epiro TTS, Pinheiro ET, Simionato MRL, Taniwaki NN, Kisielius JJ, Mayer MPA. Lineage variability in surface components expression within Porphyromonas gingivalis. Microb Pathog 2014; 77:100-4. [PMID: 25448131 DOI: 10.1016/j.micpath.2014.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 10/09/2014] [Accepted: 11/03/2014] [Indexed: 11/26/2022]
Abstract
The periodontopathogen Porphyromonas gingivalis is represented by a spectrum of phenotypes ranging from commensals to pathogenic lineages. Capsule and fimbriae are considered key virulence factors in this specie, involved in colonization and host defenses evasion. Since these virulence traits may not be expressed by certain strains, we aimed to test the hypothesis that certain clusters or genotypes of P. gingivalis correlate with the production of capsule and fimbriae. Sixteen P. gingivalis isolates were evaluated. Capsule (K) was detected by optical microscopy of negatively stained cells. The presence of fimbriae (F) was determined by TEM. Genotypes were determined by NotI macrorestriction fragments analysis through Pulsed-Field Gel Electrophoresis (PFGE) and Multi-locus sequence typing (MLST) based on seven house-keeping genes. The phenotypes included F(+)K(+) (n = 4), F(-)K(+) (n = 5), F(+)K(-) (n = 5) and F(-)K(-) (n = 2). The analysis of whole genome macrorestriction fragments revealed 14 different clusters. MLST data also revealed extensive genetic diversity; however, PFGE and MLST profiles showed evident differences. There was no association between P. gingivalis clusters and encapsulated and/or fimbriated phenotypes. Genotyping methods were not able to discriminate isolates according to the production of virulence factors such as capsule and major fimbriae, indicating that recombination played a key role in the expression of capsule and fimbriae in P. gingivalis.
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Affiliation(s)
- Silvia Regina Loureiro Teixeira
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP 05508-900, Brazil.
| | - Talyta Thereza Soares D'Epiro
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP 05508-900, Brazil.
| | - Ericka Tavares Pinheiro
- Department of Endodontics, School of Dentistry, University of São Paulo, Av. Prof. Lineu Prestes, 2227, São Paulo, SP 05508-900, Brazil.
| | - Maria Regina L Simionato
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP 05508-900, Brazil.
| | - Noemi Nosomi Taniwaki
- Department of Electron Microscopy, Adolfo Lutz Institute, Av Dr. Arnaldo, 355, São Paulo, SP 01246-902, Brazil.
| | - Jonas José Kisielius
- Department of Electron Microscopy, Adolfo Lutz Institute, Av Dr. Arnaldo, 355, São Paulo, SP 01246-902, Brazil.
| | - Marcia Pinto Alves Mayer
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP 05508-900, Brazil.
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7
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Mishra AK, Dufour H, Roche PH, Lonjon M, Raoult D, Fournier PE. Molecular revolution in the diagnosis of microbial brain abscesses. Eur J Clin Microbiol Infect Dis 2014; 33:2083-93. [DOI: 10.1007/s10096-014-2166-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 05/15/2014] [Indexed: 12/30/2022]
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8
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Teles R, Teles F, Frias-Lopez J, Paster B, Haffajee A. Lessons learned and unlearned in periodontal microbiology. Periodontol 2000 2014; 62:95-162. [PMID: 23574465 PMCID: PMC3912758 DOI: 10.1111/prd.12010] [Citation(s) in RCA: 233] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.
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9
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Watanabe T, Nozawa T, Aikawa C, Amano A, Maruyama F, Nakagawa I. CRISPR regulation of intraspecies diversification by limiting IS transposition and intercellular recombination. Genome Biol Evol 2013; 5:1099-114. [PMID: 23661565 PMCID: PMC3698921 DOI: 10.1093/gbe/evt075] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mobile genetic elements (MGEs) and genetic rearrangement are considered as major driving forces of bacterial diversification. Previous comparative genome analysis of Porphyromonas gingivalis, a pathogen related to periodontitis, implied such an important relationship. As a counterpart system to MGEs, clustered regularly interspaced short palindromic repeats (CRISPRs) in bacteria may be useful for genetic typing. We found that CRISPR typing could be a reasonable alternative to conventional methods for characterizing phylogenetic relationships among 60 highly diverse P. gingivalis isolates. Examination of genetic recombination along with multilocus sequence typing suggests the importance of such events between different isolates. MGEs appear to be strategically located at the breakpoint gaps of complicated genome rearrangements. Of these MGEs, insertion sequences (ISs) were found most frequently. CRISPR analysis identified 2,150 spacers that were clustered into 1,187 unique ones. Most of these spacers exhibited no significant nucleotide similarity to known sequences (97.6%: 1,158/1,187). Surprisingly, CRISPR spacers exhibiting high nucleotide similarity to regions of P. gingivalis genomes including ISs were predominant. The proportion of such spacers to all the unique spacers (1.6%: 19/1,187) was the highest among previous studies, suggesting novel functions for these CRISPRs. These results indicate that P. gingivalis is a bacterium with high intraspecies diversity caused by frequent insertion sequence (IS) transposition, whereas both the introduction of foreign DNA, primarily from other P. gingivalis cells, and IS transposition are limited by CRISPR interference. It is suggested that P. gingivalis CRISPRs could be an important source for understanding the role of CRISPRs in the development of bacterial diversity.
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Affiliation(s)
- Takayasu Watanabe
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Japan.
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10
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Tribble GD, Kerr JE, Wang BY. Genetic diversity in the oral pathogen Porphyromonas gingivalis: molecular mechanisms and biological consequences. Future Microbiol 2013; 8:607-20. [PMID: 23642116 DOI: 10.2217/fmb.13.30] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that colonizes the human oral cavity. It is implicated in the development of periodontitis, a chronic periodontal disease affecting half of the adult population in the USA. To survive in the oral cavity, these bacteria must colonize dental plaque biofilms in competition with other bacterial species. Long-term survival requires P. gingivalis to evade host immune responses, while simultaneously adapting to the changing physiology of the host and to alterations in the plaque biofilm. In reflection of this highly variable niche, P. gingivalis is a genetically diverse species and in this review the authors summarize genetic diversity as it relates to pathogenicity in P. gingivalis. Recent studies revealing a variety of mechanisms by which adaptive changes in genetic content can occur are also reviewed. Understanding the genetic plasticity of P. gingivalis will provide a better framework for understanding the host-microbe interactions associated with periodontal disease.
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Affiliation(s)
- Gena D Tribble
- Department of Periodontics, School of Dentistry, University of Texas Health Science Center at Houston, Houston, TX 77054, USA.
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Mo S, You M, Su YCF, Lacap-Bugler DC, Huo YB, Smith GJD, Leung WK, Watt RM. Multilocus sequence analysis of Treponema denticola strains of diverse origin. BMC Microbiol 2013; 13:24. [PMID: 23379917 PMCID: PMC3574001 DOI: 10.1186/1471-2180-13-24] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 01/24/2013] [Indexed: 01/19/2023] Open
Abstract
Background The oral spirochete bacterium Treponema denticola is associated with both the incidence and severity of periodontal disease. Although the biological or phenotypic properties of a significant number of T. denticola isolates have been reported in the literature, their genetic diversity or phylogeny has never been systematically investigated. Here, we describe a multilocus sequence analysis (MLSA) of 20 of the most highly studied reference strains and clinical isolates of T. denticola; which were originally isolated from subgingival plaque samples taken from subjects from China, Japan, the Netherlands, Canada and the USA. Results The sequences of the 16S ribosomal RNA gene, and 7 conserved protein-encoding genes (flaA, recA, pyrH, ppnK, dnaN, era and radC) were successfully determined for each strain. Sequence data was analyzed using a variety of bioinformatic and phylogenetic software tools. We found no evidence of positive selection or DNA recombination within the protein-encoding genes, where levels of intraspecific sequence polymorphism varied from 18.8% (flaA) to 8.9% (dnaN). Phylogenetic analysis of the concatenated protein-encoding gene sequence data (ca. 6,513 nucleotides for each strain) using Bayesian and maximum likelihood approaches indicated that the T. denticola strains were monophyletic, and formed 6 well-defined clades. All analyzed T. denticola strains appeared to have a genetic origin distinct from that of ‘Treponema vincentii’ or Treponema pallidum. No specific geographical relationships could be established; but several strains isolated from different continents appear to be closely related at the genetic level. Conclusions Our analyses indicate that previous biological and biophysical investigations have predominantly focused on a subset of T. denticola strains with a relatively narrow range of genetic diversity. Our methodology and results establish a genetic framework for the discrimination and phylogenetic analysis of T. denticola isolates, which will greatly assist future biological and epidemiological investigations involving this putative ‘periodontopathogen’.
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Affiliation(s)
- Sisu Mo
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Sai Ying Pun, Hong Kong
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Sreenivasan P, Haraszthy V, Zambon J. Antimicrobial efficacy of 0·05% cetylpyridinium chloride mouthrinses. Lett Appl Microbiol 2012; 56:14-20. [DOI: 10.1111/lam.12008] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 09/29/2012] [Accepted: 09/30/2012] [Indexed: 12/19/2022]
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Natural competence is a major mechanism for horizontal DNA transfer in the oral pathogen Porphyromonas gingivalis. mBio 2012; 3:mBio.00231-11. [PMID: 22294679 PMCID: PMC3268665 DOI: 10.1128/mbio.00231-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Porphyromonas gingivalis is a Gram-negative anaerobe that resides exclusively in the human oral cavity. Long-term colonization by P. gingivalis requires the bacteria to evade host immune responses while adapting to the changing host physiology and alterations in the composition of the oral microflora. The genetic diversity of P. gingivalis appears to reflect the variability of its habitat; however, little is known about the molecular mechanisms generating this diversity. Previously, our research group established that chromosomal DNA transfer occurs between P. gingivalis strains. In this study, we examine the role of putative DNA transfer genes in conjugation and transformation and demonstrate that natural competence mediated by comF is the dominant form of chromosomal DNA transfer, with transfer by a conjugation-like mechanism playing a minor role. Our results reveal that natural competence mechanisms are present in multiple strains of P. gingivalis, and DNA uptake is not sensitive to DNA source or modification status. Furthermore, extracellular DNA was observed for the first time in P. gingivalis biofilms and is predicted to be the major DNA source for horizontal transfer and allelic exchange between strains. We propose that exchange of DNA in plaque biofilms by a transformation-like process is of major ecological importance in the survival and persistence of P. gingivalis in the challenging oral environment. P. gingivalis colonizes the oral cavities of humans worldwide. The long-term persistence of these bacteria can lead to the development of chronic periodontitis and host morbidity associated with tooth loss. P. gingivalis is a genetically diverse species, and this variability is believed to contribute to its successful colonization and survival in diverse human hosts, as well as evasion of host immune defenses and immunization strategies. We establish here that natural competence is the major driving force behind P. gingivalis DNA exchange and that conjugative DNA transfer plays a minor role. Furthermore, we reveal for the first time the presence of extracellular DNA in P. gingivalis biofilms, which is most likely the source of DNA exchanged between strains within dental plaque. These studies expand our understanding of the mechanisms used by this important member of the human oral flora to transition its relationship with the host from a commensal to a pathogenic relationship.
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Enersen M. Porphyromonas gingivalis: a clonal pathogen?: Diversities in housekeeping genes and the major fimbriae gene. J Oral Microbiol 2011; 3:JOM-3-8487. [PMID: 22125739 PMCID: PMC3223970 DOI: 10.3402/jom.v3i0.8487] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/20/2011] [Accepted: 10/26/2011] [Indexed: 01/31/2023] Open
Abstract
The introduction of multilocus sequence typing (MLST) in infectious disease research has allowed standardized typing of bacterial clones. Through multiple markers around the genome, it is possible to determine the sequence type (ST) of bacterial isolates to establish the population structure of a species. For the periodontal pathogen, Porphyromonas gingivalis, the MLST scheme has been established at www.pubmlst.org/pgingivalis, and data from the database indicate a high degree of genetic diversity and a weakly clonal population structure comparable with Neisseria menigitidis. The major fimbriae (FimA) have been held responsible for the adhesive properties of P. gingivalis and represent an important virulence factor. The fimA genotyping method (PCR based) indicate that fimA genotype II, IV and Ib are associated with diseased sites in periodontitis and tissue specimens from cardiovascular disease. fimA genotyping of the isolates in the MLST database supports the association of genotypes II and IV with periodontitis. As a result of multiple positive PCR reactions in the fimA genotyping, sequencing of the fimA gene revealed only minor nucleotide variation between isolates of the same and different genotypes, suggesting that the method should be redesigned or re-evaluated. Results from several investigations indicate a higher intraindividual heterogeneity of P. gingivalis than found earlier. Detection of multiple STs from one site in several patients with "refractory" periodontitis, showed allelic variation in two housekeeping genes indicating recombination between different clones within the periodontal pocket.
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Affiliation(s)
- Morten Enersen
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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Sakamoto M, Ohkuma M. Identification and classification of the genus Bacteroides by multilocus sequence analysis. MICROBIOLOGY-SGM 2011; 157:3388-3397. [PMID: 21948050 DOI: 10.1099/mic.0.052332-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Multilocus sequence analysis (MLSA) was performed on representative species of the genus Bacteroides. Internal fragments of the genes selected, dnaJ, gyrB, hsp60, recA, rpoB and 16S rRNA, were amplified by direct PCR and then sequenced from 38 Bacteroides strains representing 35 species. Neighbour-joining (NJ), maximum-likelihood (ML) and maximum-parsimony (MP) phylogenies of the individual genes were compared. The data confirm that the potential for discrimination of Bacteroides species is greater using MLSA of housekeeping genes than 16S rRNA genes. Among the housekeeping genes analysed, gyrB was the most informative, followed by dnaJ. Analyses of concatenated sequences (4816 bp) of all six genes revealed robust phylogenetic relationships among different Bacteroides species when compared with the single-gene trees. The NJ, ML and MP trees were very similar, and almost fully resolved relationships of Bacteroides species were obtained, to our knowledge for the first time. In addition, analysis of a concatenation (2457 bp) of the dnaJ, gyrB and hsp60 genes produced essentially the same result. Ten distinct clades were recognized using the SplitsTree4 program. For the genus Bacteroides, we can define species as a group of strains that share at least 97.5% gene sequence similarity based on the fragments of five protein-coding housekeeping genes and the 16S rRNA gene. This study demonstrates that MLSA of housekeeping genes is a valuable alternative technique for the identification and classification of species of the genus Bacteroides.
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Affiliation(s)
- Mitsuo Sakamoto
- Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center, Wako, Saitama 351-0198, Japan
| | - Moriya Ohkuma
- Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center, Wako, Saitama 351-0198, Japan
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Do T, Gilbert S, Klein J, Warren S, Wade W, Beighton D. Clonal structure of Streptococcus sanguinis strains isolated from endocarditis cases and the oral cavity. Mol Oral Microbiol 2011; 26:291-302. [DOI: 10.1111/j.2041-1014.2011.00618.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Fargier E, Fischer-Le Saux M, Manceau C. A multilocus sequence analysis of Xanthomonas campestris reveals a complex structure within crucifer-attacking pathovars of this species. Syst Appl Microbiol 2010; 34:156-65. [PMID: 21193279 DOI: 10.1016/j.syapm.2010.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 07/28/2010] [Accepted: 09/27/2010] [Indexed: 10/18/2022]
Abstract
Previous classification of Xanthomonas campestris has defined six pathovars (aberrans, armoraciae, barbareae, campestris, incanae, and raphani) that cause diseases on cruciferous plants. However, pathogenicity assays with a range of strains and different hosts identifies only three types of symptom: black rot, leaf spot and bacterial blight. These findings raise the question of the genetic relatedness between strains assigned to different pathovars or symptom phenotypes. Here we have addressed this issue by multilocus sequence analysis of 42 strains. The X. campestris species was polymorphic at the 8 loci analysed and had a high genetic diversity; 23 sequence types were identified of which 16 were unique. All strains that induce black rot (pathovars aberrans and campestris) were genetically close but split in two groups. Only three clonal complexes were found, all within pathovar campestris. The assignment of the genome-sequenced strain 756C to pathovar raphani suggested from disease symptoms was confirmed, although this group of strains was particularly polymorphic. Strains belonging to pathovars barbareae and incanae were closely related, but distinct from pathovar campestris. There is evidence of genetic exchanges of housekeeping genes within this species as deduced from a clear incongruence between individual gene phylogenies and from network structures from SplitsTree analysis. Overall this study showed that the high genetic diversity derived equally from recombination and point mutation accumulation. However, X. campestris remains a species with a clonal evolution driven by a differential adaptation to cruciferous hosts.
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Affiliation(s)
- E Fargier
- INRA, UMR A77 Pathologie Végétale, 42 rue Georges Morel, B.P. 60057, F-49070 Beaucouzé, France
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Kuboniwa M, Inaba H, Amano A. Genotyping to distinguish microbial pathogenicity in periodontitis. Periodontol 2000 2010; 54:136-59. [DOI: 10.1111/j.1600-0757.2010.00352.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Lin L, Li C, Liu J, Zhang D, Zhao J, Kou Y, Yu N, Pan Y. Virulence genes of Porphyromonas gingivalis W83 in chronic periodontitis. Acta Odontol Scand 2009; 67:258-64. [PMID: 22443638 DOI: 10.1080/00016350902841890] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To identify virulence genes found in highly virulent strains of Porphyromonas gingivalis (P. gingivalis) among Chinese patients with chronic periodontitis and to evaluate the association of these virulence genes with clinical parameters and with periodontal tissue destruction. MATERIAL AND METHODS Suppression subtractive hybridization was applied to acquire short gene fragments harbored only in virulent strains of P. gingivalis W83. Eighteen genes, which were present in P. gingivalis W83 but absent from P. gingivalis ATCC 33277, were labeled with Cy5 and used as probes in DNA microarray hybridization to analyze DNA of P. gingivalis isolated from chronic periodontitis patients. RESULTS Spearman correlation analysis revealed 10 genes correlated with probing depth, clinical attachment loss, and tooth mobility (p<0.05). CONCLUSION These genes may provide an important clue towards our understanding the mechanism of occurrence and the development of periodontal disease.
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Microbial changes in periodontitis successfully treated by mechanical plaque removal and systemic amoxicillin and metronidazole. Int J Med Microbiol 2009; 299:427-38. [DOI: 10.1016/j.ijmm.2009.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 03/01/2009] [Indexed: 11/24/2022] Open
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Do T, Jolley KA, Maiden MCJ, Gilbert SC, Clark D, Wade WG, Beighton D. Population structure of Streptococcus oralis. MICROBIOLOGY-SGM 2009; 155:2593-2602. [PMID: 19423627 PMCID: PMC2885674 DOI: 10.1099/mic.0.027284-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Streptococcus oralis is a member of the normal human oral microbiota, capable of opportunistic pathogenicity; like related oral streptococci, it exhibits appreciable phenotypic and genetic variation. A multilocus sequence typing (MLST) scheme for S. oralis was developed and the resultant data analysed to examine the population structure of the species. Analysis of 113 isolates, confirmed as belonging to the S. oralis/mitis group by 16S rRNA gene sequencing, characterized the population as highly diverse and undergoing inter- and intra-species recombination with a probable clonal complex structure. ClonalFrame analysis of these S. oralis isolates along with examples of Streptococcus pneumoniae, Streptococcus mitis and Streptococcus pseudopneumoniae grouped the named species into distinct, coherent populations and did not support the clustering of S. pseudopneumoniae with S. mitis as reported previously using distance-based methods. Analysis of the individual loci suggested that this discrepancy was due to the possible hybrid nature of S. pseudopneumoniae. The data are available on the public MLST website (http://pubmlst.org/soralis/).
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Affiliation(s)
- Thuy Do
- King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK
- Biomedical Research Centre, Guy's and St Thomas' Hospital NHS Foundation Trust, London SE1 9RT, UK
| | - Keith A. Jolley
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | | | - Steven C. Gilbert
- King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK
- Biomedical Research Centre, Guy's and St Thomas' Hospital NHS Foundation Trust, London SE1 9RT, UK
| | - Douglas Clark
- King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK
| | - William G. Wade
- King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK
| | - David Beighton
- King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK
- Biomedical Research Centre, Guy's and St Thomas' Hospital NHS Foundation Trust, London SE1 9RT, UK
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Rylev M, Kilian M. Prevalence and distribution of principal periodontal pathogens worldwide. J Clin Periodontol 2009; 35:346-61. [PMID: 18724862 DOI: 10.1111/j.1600-051x.2008.01280.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Detailed genetic analysis of bacteria has demonstrated an unanticipated genetic diversity within species, which often reveals evolutionary lineages that are disproportionately associated with infection. There is evidence that some evolutionary lineages of bacteria have adapted to particular ethnic groups. AIM This review analyzes to what extent observed differences in periodontal disease prevalence among ethnically or geographically distinct populations may be explained by restricted host adaptation of clones of principal periodontal pathogens. RESULTS Carriage rates of several putative periodontal pathogens and particular subsets of these species vary between ethnic groups. Few of these differences can, with the limited information available, be directly related to differences in periodontal disease prevalence. Asian populations are regularly colonized with Actinobacillus actinomycetemcomitans serotype c with questionable pathogenic potential. Conversely, the JP2 clone of A. actinomycetemcomitans has enhanced virulence and causes significantly higher prevalence of aggressive periodontitis in adolescents whose descent can be traced back to the Mediterranean and Western parts of Africa. Some genetically distinct types of Porphyromonas gingivalis are more associated with disease than others, but additional work is required to relate this to clinical differences. CONCLUSIONS Studies that take into account differences linked to the genetics of both patients and potential pathogens are likely to give better insight into the aetiology of periodontal diseases.
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Affiliation(s)
- Mette Rylev
- Institute of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.
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Vos M, Didelot X. A comparison of homologous recombination rates in bacteria and archaea. ISME JOURNAL 2008; 3:199-208. [PMID: 18830278 DOI: 10.1038/ismej.2008.93] [Citation(s) in RCA: 387] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
It is a standard practice to test for the signature of homologous recombination in studies examining the genetic diversity of bacterial populations. Although it has emerged that homologous recombination rates can vary widely between species, comparing the results from different studies is made difficult by the diversity of estimation methods used. Here, Multi Locus Sequence Typing (MLST) datasets from a wide variety of bacteria and archaea are analyzed using the ClonalFrame method. This enables a direct comparison between species and allows for a first exploration of the question whether phylogeny or ecology is the primary determinant of homologous recombination rate.
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Affiliation(s)
- Michiel Vos
- Department of Zoology, University of Oxford, Oxford, UK.
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van Winkelhoff AJ, Rijnsburger MC, van der Velden U. Clonal stability ofPorphyromonas gingivalisin untreated periodontitis. J Clin Periodontol 2008; 35:674-9. [DOI: 10.1111/j.1600-051x.2008.01285.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Pérez-Chaparro PJ, Gracieux P, Lafaurie GI, Donnio PY, Bonnaure-Mallet M. Genotypic characterization of Porphyromonas gingivalis isolated from subgingival plaque and blood sample in positive bacteremia subjects with periodontitis. J Clin Periodontol 2008; 35:748-53. [PMID: 18662301 DOI: 10.1111/j.1600-051x.2008.01296.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM The objective of this study was to investigate clonal relationship among Porphyromonas gingivalis isolated from subgingival plaque and blood samples in positive transient bacteremia subjects with periodontitis. MATERIAL AND METHODS Unrelated patients with general chronic periodontitis or general aggressive periodontitis requiring scaling and root planing (SRP) were included in the study. Genotyping of each isolate was performed using pulsed field gel electrophoresis technique. Genetic relatedness of strains isolated within an individual or between different patients was determined by dendogram analysis. RESULTS Following SRP, from 16 patients, seven patients showed positive P. gingivalis bacteremia and nine were negative. Thirty-two strains were isolated from subgingival plaque and blood samples before and during induced transient bacteremia. The majority of the patients harboured one clonal type. Two patients showed different clones in plaque and blood samples suggesting that more than one clone can be found in subgingival plaque. P. gingivalis isolates from periodontitis patients after transient bacteremia following SRP, revealed a high heterogeneity among isolates. CONCLUSION In 6/16 subjects the same P. gingivalis isolate was found in the blood and in oral cavity. P. gingivalis heterogeneity suggests no association of a unique clonal type with transient bacteremia.
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Affiliation(s)
- P Juliana Pérez-Chaparro
- Equipe de Microbiologie EA 1254, Université Européenne de Bretagne, Université de Rennes 1, Rennes, France
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Genetic diversity of Porphyromonas gingivalis isolates recovered from single "refractory" periodontitis sites. Appl Environ Microbiol 2008; 74:5817-21. [PMID: 18641158 DOI: 10.1128/aem.00225-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multilocus sequence typing and fimA genotyping were performed on Porphyromonas gingivalis isolates from 15 subjects with "refractory" periodontitis. Several sequence types were detected for most individual pockets. The variation indicated recombination at the recA and pepO genes. The prevalence of fimA genotypes II and IV confirmed their association with periodontitis.
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fimA genotypes and multilocus sequence types of Porphyromonas gingivalis from patients with periodontitis. J Clin Microbiol 2007; 46:31-42. [PMID: 17977992 DOI: 10.1128/jcm.00986-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fimbriae are important virulence factors of pathogenic bacteria, facilitating their attachment to host and bacterial cells. In the periodontal pathogen Porphyromonas gingivalis, the fimA gene is classified into six types (genotypes I, Ib, II, III, IV, and V) on the basis of different nucleotide sequences, with fimA genotypes II and IV being prevalent in isolates from patients with periodontitis. The aims of this study were to examine the distribution of fimA genotypes in a collection of 82 P. gingivalis isolates from adult periodontitis patients of worldwide origin and to investigate the relationship between the fimA genotypes and the sequence types (STs), as determined by multilocus sequence typing (MLST), of the isolates. The fimA gene was amplified by PCR with primer sets specific for each genotype. The STs of all strains were assigned according to the MLST database for P. gingivalis (www.pubmlst.org/pgingivalis). The 82 strains showed extensive genetic diversity and were assigned to 69 STs. Only isolates with closely related STs harbored the same fimA genotype. Twenty-eight (34.1%) strains harbored fimA genotype II, while only the reference strain for fimA genotype V reacted with the primers specific for this genotype. Twenty-one isolates (25.6%) were positive by more than one of the fimA PCR assays; the most frequent combinations were genotypes I, Ib, and II (eight isolates) and genotypes I and II (four isolates). Sequencing of the fimA gene from selected isolates did not support the observed specific fimA genotype combinations, suggesting that the genotyping method used for the major fimbriae in P. gingivalis should be reevaluated.
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Yoshino T, Laine ML, van Winkelhoff AJ, Dahlén G. Genotypic characterization of Porphyromonas gingivalis isolated from Swedish patients with periodontitis and from periodontal abscesses. ACTA ACUST UNITED AC 2007; 22:195-200. [PMID: 17488446 DOI: 10.1111/j.1399-302x.2007.00350.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION A significant genetic polymorphism has been shown for Porphyromonas gingivalis isolates from different geographical areas. It is, however, possible that genetic similarities can be found among isolates obtained from a more specific population. The aim of the present study was to evaluate genetic heterogeneity among P. gingivalis isolates obtained from Swedish subjects with chronic periodontitis and from periodontal abscess lesions. METHODS A total of 78 P. gingivalis strains, including 55 fresh clinical isolates obtained from 52 Swedish periodontitis subjects, eight isolates from eight Swedish periodontal abscess subjects and 15 reference strains, were subjected to amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) genotyping assays. RESULTS A total of 62 AFLP genotypes and 70 RAPD genotypes were identified among the 78 P. gingivalis strains. Forty-six strains were clustered at 70% similarity level into 15 clusters. Six identical RAPD genotypes were identified among the strains. The AFLP/RAPD profiles were compared for identical genotypes. A total of 56 AFLP/RAPD genotypes were found. Four pairs of identical AFLP/RAPD genotypes were found for two strains obtained from two different periodontal pockets each of four subjects. Interestingly, two strains showed an RAPD/AFLP genotype, which was identical to the type strain W83. CONCLUSION The present study demonstrated that Swedish P. gingivalis isolates exhibit a wide variety of genotypes with only a weak clustering pattern. No predominant genotype at the whole chromosomal DNA level was present among Swedish P. gingivalis strains.
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Affiliation(s)
- T Yoshino
- Department of Oral Microbiology, Institute of Odontology, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden
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Tribble GD, Lamont GJ, Progulske-Fox A, Lamont RJ. Conjugal transfer of chromosomal DNA contributes to genetic variation in the oral pathogen Porphyromonas gingivalis. J Bacteriol 2007; 189:6382-8. [PMID: 17573478 PMCID: PMC1951918 DOI: 10.1128/jb.00460-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porphyromonas gingivalis is a major oral pathogen that contributes to the development of periodontal disease. There is a significant degree of genetic variation among strains of P. gingivalis, and the population structure has been predicted to be panmictic, indicating that horizontal DNA transfer and recombination between strains are likely. The molecular events underlying this genetic exchange are not understood, although a putative type IV secretion system is present in the genome sequence of strain W83, implying that DNA conjugation may be responsible for genetic transfer in these bacteria. In this study, we provide in vitro evidence for the horizontal transfer of DNA using plasmid- and chromosome-based assays. In the plasmid assays, Bacteroides-derived shuttle vectors were tested for transfer from P. gingivalis strains into Escherichia coli. Of the eight strains tested, five were able to transfer DNA into E. coli by a mechanism most consistent with conjugation. Additionally, strains W83 and 33277 tested positive for the transfer of chromosomally integrated antibiotic resistance markers. Ten chimeras resulting from the chromosomal transfer assay were further analyzed by Southern hybridization and were shown to have exchanged DNA fragments of between 1.1 and 5.6 kb, but the overall strain identity remained intact. Chimeras showed phenotypic changes in the ability to accrete into biofilms, implying that DNA transfer events are sufficient to generate measurable changes in complex behaviors. This ability to transfer chromosomal DNA between strains may be an adaptation mechanism in the complex environment of the host oral cavity.
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Affiliation(s)
- Gena D Tribble
- Department of Oral Biology and Center for Molecular Microbiology, College of Dentistry, University of Florida, Gainesville 32610-0424, USA.
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Kato T, Kawai S, Nakano K, Inaba H, Kuboniwa M, Nakagawa I, Tsuda K, Omori H, Ooshima T, Yoshimori T, Amano A. Virulence of Porphyromonas gingivalis is altered by substitution of fimbria gene with different genotype. Cell Microbiol 2006; 9:753-65. [PMID: 17081195 DOI: 10.1111/j.1462-5822.2006.00825.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Porphyromonas gingivalis is a periodontal pathogen whose fimbriae are classified into six genotypes based on the diversity of the fimA genes encoding each fimbria subunit. It was suggested that P. gingivalis strains with type II fimbriae were more virulent than type I strains. For the present study, we generated the mutants in which fimA was substituted with different genotypes to study virulence of type II fimbriae. Using plasmid vectors, fimA of ATCC33277 (type I strain) was substituted with type II fimA, and that of OMZ314 (type II strain) with type I fimA. The substitution of type I fimA with type II enhanced bacterial adhesion/invasion to epithelial cells, whereas substitution with type I fimA resulted in diminished efficiency. Following bacterial invasion, type II clones swiftly degraded cellular paxillin and focal adhesion kinase, and inhibited cellular migration, whereas type I clones and DeltafimA mutants did not. BIAcore analysis demonstrated that type II fimbriae possess greater adhesive abilities for their receptor alpha5beta1-integrin than those of type I. In a mouse abscess model, the type II clones significantly induced serum IL-1beta and IL-6, as well as other infectious symptoms. These results suggest that type II fimbriae are a critical determinant of P. gingivalis virulence.
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Affiliation(s)
- Takahiro Kato
- Department of Oral Frontier Biology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
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