1
|
Soza-Bolaños AI, Domínguez-Pérez RA, Ayala-Herrera JL, Pérez-Serrano RM, Soto-Barreras U, Espinosa-Cristóbal LF, Rivera-Albarrán CA, Zaldívar-Lelo de Larrea G. Presence of methanogenic archaea in necrotic root canals of patients with or without type 2 diabetes mellitus. AUST ENDOD J 2023; 49:641-647. [PMID: 37715368 DOI: 10.1111/aej.12797] [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: 01/04/2023] [Revised: 08/11/2023] [Accepted: 09/04/2023] [Indexed: 09/17/2023]
Abstract
Theoretically, a necrotic root canal fulfils all requirements as a niche for methanogens to inhabit. However, their presence in it and its implication in apical periodontitis (AP) is controversial. Therefore, to contribute to ending the controversy, this study aimed to detect and compare methanogens' presence in two distinct niches with supposedly different microenvironments; both were necrotic root canals associated with AP but one from patients with type 2 diabetes mellitus (T2DM) while the other from non-diabetic patients. A clinical examination was performed on 65 T2DM patients and 73 non-diabetic controls. Samples from necrotic root canals were obtained, and methanogens were identified. The presence of methanogens was three times higher (27.6%) in the T2DM group than in non-diabetic patients (8.2%). In addition, methanogens' presence was associated with a higher prevalence of periapical symptoms.
Collapse
Affiliation(s)
- Ana I Soza-Bolaños
- Laboratory of Multidisciplinary Dentistry Research, Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
- Department of Endodontics, Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
| | - Rubén A Domínguez-Pérez
- Laboratory of Multidisciplinary Dentistry Research, Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
- Department of Endodontics, Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
| | | | - Rosa M Pérez-Serrano
- Laboratorio de Genética y Biología Molecular (GENBIOM), Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
| | | | - León F Espinosa-Cristóbal
- Master Program in Dental Sciences, Stomatology Department, Institute of Biomedical Sciences, Autonomous University of Juarez, Ciudad Juarez, Mexico
| | - Claudia A Rivera-Albarrán
- Laboratory of Multidisciplinary Dentistry Research, Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
| | - Guadalupe Zaldívar-Lelo de Larrea
- Laboratorio de Genética y Biología Molecular (GENBIOM), Facultad de Medicina, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico
| |
Collapse
|
2
|
Cena JA, Vasques Castro JAD, Belmok A, Sales LP, Alves de Oliveira L, Stefani CM, Dame-Teixeira N. Unraveling the Endodontic Archaeome: A Systematic Review with Meta-Analysis. J Endod 2023; 49:1432-1444.e4. [PMID: 37544428 DOI: 10.1016/j.joen.2023.07.025] [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: 04/25/2023] [Revised: 07/26/2023] [Accepted: 07/29/2023] [Indexed: 08/08/2023]
Abstract
INTRODUCTION The controversial issue of whether the Archaea domain plays a role in endodontic infections is the focus of this systematic review with meta-analysis. The aim is to emphasize the significance of minority microbial domains in oral dysbiosis by evaluating the prevalence of archaea in root canals and its association with clinical parameters such as symptomatology and type of endodontic infection. METHODS The search strategy involved researching 6 databases and the gray literature. Publications were accepted in any year or language that identified archaea in samples from endodontic canals. A 2-step selection process narrowed the final choice to 16 articles. The methodological quality of the studies was evaluated using tools from the Joanna Briggs Institute, and the certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. RESULTS The results showed that archaea were present in 20% (95% [confidence interval] CI = 8%-32%) of individuals with endodontic samples analyzed. The samples were about twice as likely to be archaeal-positive if collected from individuals with primary vs. persistent/secondary infection (odds ratio = 2.33; 95% CI = 1.31-4.14; I2 = 0%), or individuals with self-reported vs. symptom-free infections (odds ratio = 2.67; 95% CI = 1.47-4.85; I2 = 0%). Methanogenic archaea were reported in 66% of the included studies. Representative members of phyla Thaumarchaeota and Crenarchaeota were also identified. CONCLUSIONS Archaea are present in about one-fifth of the infected root canals. Recognized biases in experimental approaches for researching archaea must be addressed to understand the prevalence and roles of archaea in endodontic infections, and to determine whether the decontamination process should include the elimination or neutralization of archaea from root canals (International Prospective Register of Systematic Reviews protocol = CRD42021264308).
Collapse
Affiliation(s)
- Jessica Alves Cena
- Department of Dentistry, School of Health Sciences, University of Brasilia, Brasilia, Brazil
| | | | - Aline Belmok
- Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Loise Pedrosa Sales
- Department of Dentistry, School of Health Sciences, University of Brasilia, Brasilia, Brazil
| | | | - Cristine Miron Stefani
- Department of Dentistry, School of Health Sciences, University of Brasilia, Brasilia, Brazil
| | - Naile Dame-Teixeira
- Department of Dentistry, School of Health Sciences, University of Brasilia, Brasilia, Brazil; Oral Biology Division, School of Dentistry, University of Leeds, Leeds, UK.
| |
Collapse
|
3
|
Siqueira JF, Rôças IN. Present status and future directions - microbiology of endodontic infections. Int Endod J 2021; 55 Suppl 3:512-530. [PMID: 34958494 DOI: 10.1111/iej.13677] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/22/2021] [Accepted: 12/26/2021] [Indexed: 11/29/2022]
Abstract
Apical periodontitis has a microbial aetiology and is one of the most common inflammatory diseases that affect humans. Fungi, archaea and viruses have been found in association with apical periodontitis, but bacteria are by far the most prevalent and dominant microorganisms in endodontic infections. Bacterial infection of the root canal system only occurs when the pulp is necrotic or was removed for previous treatment. In some specific cases, including acute and chronic abscesses, the bacterial infection may reach the periradicular tissues. Intracanal bacteria are usually observed as sessile multispecies communities (biofilms) attached to the dentinal root canal walls. Infection in the main root canal lumen can spread to other areas of the root canal system. Although more than 500 bacterial species have been detected in endodontic infections, a selected group of 20 to 30 species are most frequently detected and may be considered as the core microbiome. There is a high interindividual variability in the endodontic microbiome in terms of species composition and relative abundance. Obligate anaerobic species are more abundant in the intraradicular bacterial communities of teeth with primary apical periodontitis, while both anaerobes and facultatives dominate the communities in post-treatment apical periodontitis. Bacterial interactions play an essential role in determining the overall virulence of the community, which has been regarded as the unit of pathogenicity of apical periodontitis. This article reviews the microbiologic aspects of endodontic infections and provides perspectives for future research and directions in the field.
Collapse
Affiliation(s)
- José F Siqueira
- Department of Dental Research, Faculty of Dentistry, Iguaçu University (UNIG), Nova Iguaçu, RJ, and Department of Endodontics and Molecular Microbiology Laboratory, Faculty of Dentistry, Grande Rio University, Rio de Janeiro, RJ, Brazil
| | - Isabela N Rôças
- Department of Dental Research, Faculty of Dentistry, Iguaçu University (UNIG), Nova Iguaçu, RJ, and Department of Endodontics and Molecular Microbiology Laboratory, Faculty of Dentistry, Grande Rio University, Rio de Janeiro, RJ, Brazil
| |
Collapse
|
4
|
Abstract
The Archaea domain was recognized as a separate phylogenetic lineage in the tree of life nearly 3 decades ago. It is now known as part of the human microbiome; however, given that its roles in oral sites are still poorly understood, this review aimed to establish the current level of evidence regarding archaea in the oral cavity to guide future research, providing insights on the present knowledge about the human oral archaeome. A scoping review was conducted with the PRISMA Extension for Scoping Reviews checklist. Five electronic databases were searched, as well as gray literature. Two independent reviewers performed the selection and characterization of the studies. Clinical studies were included when the target population consisted of humans of any age who were donors of samples from the oral cavity. A qualitative analysis was performed, based on the type of oral site and by considering the methods employed for archaeal identification and taxonomy, including the DNA extraction protocols, primers, and probes used. Fifty articles were included in the final scoping review, published from 1987 to 2019. Most studies sampled periodontal sites. Methanogens were the most abundant archaea in those sites, and their presence could be associated with other periodontal pathogens. No consistent relationship with different disease conditions was observed in studies that evaluated the microbiota surviving in endodontic sites. Few articles analyzed the presence of archaea in dental caries, saliva, or tongue microbiota, as well as in archaeologic samples, also showing a relationship with healthy microbiota. Archaea have been detected in different oral niches of individuals from diverse geographic locations and clinical conditions, suggesting potential roles in oral diseases. Methodological limitations may hamper our current knowledge about archaeal diversity and prevalence in oral samples, and future research with diversified methodological approaches may lead to a better comprehension of the human oral archaeome.
Collapse
Affiliation(s)
- A Belmok
- Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, Brazil
| | - J A de Cena
- Department of Dentistry, Faculty of Heath Sciences, University of Brasília, Brasília, Brazil
| | - C M Kyaw
- Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, Brazil
| | - N Damé-Teixeira
- Department of Dentistry, Faculty of Heath Sciences, University of Brasília, Brasília, Brazil
| |
Collapse
|
5
|
Brzezińska-Błaszczyk E, Pawłowska E, Płoszaj T, Witas H, Godzik U, Agier J. Presence of archaea and selected bacteria in infected root canal systems. Can J Microbiol 2018; 64:317-326. [DOI: 10.1139/cjm-2017-0531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Infections of the root canal have polymicrobial etiology. The main group of microflora in the infected pulp is bacteria. There is limited data that archaea may be present in infected pulp tissue. The aim of this study was to check the prevalence of archaea in necrotic root canal samples obtained from patients with primary or post-treatment infection. The prevalence of selected bacteria species (Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Synergistes sp.) in necrotic samples was evaluated as well. Sixty-four samples from root canal were collected for DNA and RNA extraction. A PCR assay based on the 16S rRNA gene was used to determine the presence of archaea and selected bacteria. Of the 64 samples, 6 were analyzed by semiquantitative reverse transcription PCR to estimate expression profiles of 16S rRNA, and another 9 were selected for direct sequencing. Archaea were detected in 48.4% samples. Statistical analysis indicated a negative association in coexistence between archaea and Treponema denticola (P < 0.05; Pearson’s χ2 test). The main representative of the Archaea domain found in infected pulp tissue was Methanobrevibacter oralis. Archaea 16S rRNA gene expression was significantly lower than Synergistes sp., Porphyromonas gingivalis, and Tannerella forsythia (P < 0.05; Student’s t test). Thus, it can be hypothesized that archaea may participate in the endodontic microbial community.
Collapse
Affiliation(s)
| | | | - Tomasz Płoszaj
- Department of Molecular Biology, Medical University of Lodz, Lodz, Poland
| | - Henryk Witas
- Department of Molecular Biology, Medical University of Lodz, Lodz, Poland
| | - Urszula Godzik
- Department of Experimental Immunology, Medical University of Lodz, Lodz, Poland
| | - Justyna Agier
- Department of Experimental Immunology, Medical University of Lodz, Lodz, Poland
| |
Collapse
|
6
|
General Characteristics and Important Model Organisms. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2014. [DOI: 10.1128/9781555815516.ch2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
7
|
Medical microbiological approach to Archaea in oral infectious diseases. JAPANESE DENTAL SCIENCE REVIEW 2013. [DOI: 10.1016/j.jdsr.2013.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
8
|
Jiang YT, Xia WW, Li CL, Jiang W, Liang JP. Preliminary study of the presence and association of bacteria and archaea in teeth with apical periodontitis. Int Endod J 2010; 42:1096-103. [PMID: 19912381 DOI: 10.1111/j.1365-2591.2009.01639.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To investigate, by reverse transcription polymerase chain reaction (RT-PCR), the presence and association of bacteria and archaea in primary and secondary root canal infections. METHODOLOGY A total of 77 root canal samples from 77 Chinese patients, 42 with necrotic pulp tissues (primary infection) and 35 with failed prior conventional root canal treatment (secondary infection), aseptically exposed at the first patient visit, were studied. Total RNA was isolated directly from each sample, and 16S rRNA gene-based RT-PCR assays were used to determine the presence of bacteria and archaea, respectively. RESULTS Bacteria were detected in 39/42 (93%) of root canal samples from teeth with primary infections, and archaea in 16/42 (38%). In the cases diagnosed as secondary root-infected canals, bacteria were detected in 30/35 (86%), whilst archaea were detected in 6/35 (17%) of cases. Amongst the canals, which were positive for bacteria, archaea were always found in combination with bacteria. The incidence of symptomatic cases positive for both bacteria and archaea (16/22, 73%) were significantly higher than those positive for bacteria alone (21/47, 45%) (P < 0.05). CONCLUSIONS This study confirms the presence of archaea in root canal infections and further implicates them in an association with clinical symptoms. The nature of this association requires further study.
Collapse
Affiliation(s)
- Y T Jiang
- Department of Endodontics and Operative Dentistry, School of Stomatology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai
| | | | | | | | | |
Collapse
|
9
|
Gao Z, Tseng CH, Strober BE, Pei Z, Blaser MJ. Substantial alterations of the cutaneous bacterial biota in psoriatic lesions. PLoS One 2008; 3:e2719. [PMID: 18648509 PMCID: PMC2447873 DOI: 10.1371/journal.pone.0002719] [Citation(s) in RCA: 287] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 06/17/2008] [Indexed: 01/12/2023] Open
Abstract
For psoriasis, an idiopathic inflammatory disorder of the skin, the microbial biota has not been defined using cultivation-independent methods. We used broad-range 16S rDNA PCR for archaea and bacteria to examine the microbiota of normal and psoriatic skin. From 6 patients, 19 cutaneous samples (13 from diseased skin and 6 from normal skin) were obtained. Extracted DNA was subjected to the broad range PCR, and 1,925 cloned products were compared with 2,038 products previously reported from healthy persons. Using 98% sequence identity as a species boundary, 1,841 (95.6%) clones were similar to known bacterial 16S rDNA, representing 6 phyla, 86 genera, or 189 species-level operational taxonomic unit (SLOTU); 84 (4.4%) clones with <98% identity probably represented novel species. The most abundant and diverse phylum populating the psoriatic lesions was Firmicutes (46.2%), significantly (P<0.001) overrepresented, compared to the samples from uninvolved skin of the patients (39.0%) and healthy persons (24.4%). In contrast, Actinobacteria, the most prevalent and diverse phylum in normal skin samples from both healthy persons (47.6%) and the patients (47.8%), was significantly (P<0.01) underrepresented in the psoriatic lesion samples (37.3%). Representation of Propionibacterium species were lower in the psoriatic lesions (2.9+/-5.5%) than from normal persons (21.1+/-18.2%; P<0.001), whereas normal skin from the psoriatic patients showed intermediate levels (12.3+/-21.6%). We conclude that psoriasis is associated with substantial alteration in the composition and representation of the cutaneous bacterial biota.
Collapse
Affiliation(s)
- Zhan Gao
- Department of Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Chi-hong Tseng
- Department of Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Environmental Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Bruce E. Strober
- Department of Dermatology, New York University School of Medicine, New York, New York, United States of America
| | - Zhiheng Pei
- Department of Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Pathology, New York University School of Medicine, New York, New York, United States of America
- New York Harbor Veterans Affairs Medical Center, New York, New York, United States of America
| | - Martin J. Blaser
- Department of Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
- New York Harbor Veterans Affairs Medical Center, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
10
|
Vickerman MM, Brossard KA, Funk DB, Jesionowski AM, Gill SR. Phylogenetic analysis of bacterial and archaeal species in symptomatic and asymptomatic endodontic infections. J Med Microbiol 2007; 56:110-118. [PMID: 17172525 DOI: 10.1099/jmm.0.46835-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phylogenetic analysis of bacterial and archaeal 16S rRNA was used to examine polymicrobial communities within infected root canals of 20 symptomatic and 14 asymptomatic patients. Nucleotide sequences from approximately 750 clones amplified from each patient group with universal bacterial primers were matched to the Ribosomal Database Project II database. Phylotypes from 37 genera representing Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria were identified. Results were compared to those obtained with species-specific primers designed to detect Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis, Peptostreptococcus micros, Enterococcus sp., Streptococcus sp., Fusobacterium nucleatum, Tannerella forsythensis and Treponema denticola. Since members of the domain Archaea have been implicated in the severity of periodontal disease, and a recent report confirms that archaea are present in endodontic infections, 16S archaeal primers were also used to detect which patients carried these prokaryotes, to determine if their presence correlated with severity of the clinical symptoms. A Methanobrevibacter oralis-like species was detected in one asymptomatic and one symptomatic patient. DNA from root canals of these two patients was further analysed using species-specific primers to determine bacterial cohabitants. Trep. denticola was detected in the asymptomatic but not the symptomatic patient. Conversely, Porph. endodontalis was found in the symptomatic but not the asymptomatic patient. All other species except enterococci were detected with the species-specific primers in both patients. These results confirm the presence of archaea in root canals and provide additional insights into the polymicrobial communities in endodontic infections associated with clinical symptoms.
Collapse
Affiliation(s)
- M M Vickerman
- Department of Oral Biology, University at Buffalo School of Dentistry, Buffalo, NY, USA
- Department of Periodontics and Endodontics, University at Buffalo School of Dentistry, Buffalo, NY, USA
| | - K A Brossard
- Department of Oral Biology, University at Buffalo School of Dentistry, Buffalo, NY, USA
| | - D B Funk
- Department of Periodontics and Endodontics, University at Buffalo School of Dentistry, Buffalo, NY, USA
| | - A M Jesionowski
- Department of Oral Biology, University at Buffalo School of Dentistry, Buffalo, NY, USA
| | - S R Gill
- Department of Oral Biology, University at Buffalo School of Dentistry, Buffalo, NY, USA
| |
Collapse
|
11
|
Machado de Oliveira JC, Siqueira JF, Rôças IN, Baumgartner JC, Xia T, Peixoto RS, Rosado AS. Bacterial community profiles of endodontic abscesses from Brazilian and USA subjects as compared by denaturing gradient gel electrophoresis analysis. ACTA ACUST UNITED AC 2007; 22:14-8. [PMID: 17241165 DOI: 10.1111/j.1399-302x.2007.00311.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study compared the bacterial community profiles of the microbiota associated with acute apical abscesses from Brazilian and USA patients using denaturing gradient gel electrophoresis (DGGE). DNA was extracted from purulent exudate aspirates and part of the 16S rRNA gene was amplified by polymerase chain reaction and separated by DGGE. The resulting banding patterns, which were representative of the bacterial community structures in samples from the two locations, were then compared. Distinct DGGE banding patterns were observed from different samples. Ninety-nine bands with distinct positions in the gels were detected, of which 27 were found only in the USA samples and 13 were exclusive to Brazilian samples. Four of the 59 shared bands showed very discrepant findings with regard to prevalence in the two locations. Cluster analysis of DGGE banding profiles showed a great variability in the bacterial populations associated with teeth with abscesses regardless of the geographical location. Two big clusters, one for each location, were observed. Other clusters contained a mixture of samples from the two locations. The results of the present study demonstrated a great variability in the bacterial community profiles among samples. This indicates that the bacterial communities of abscesses are unique for each individual in terms of diversity. The composition of the microbiota in some samples showed a geography-related pattern. Furthermore, several bands were exclusive for each location and others were shared by the two locations and showed great differences in prevalence.
Collapse
|
12
|
Vianna ME, Conrads G, Gomes BPFA, Horz HP. Identification and quantification of archaea involved in primary endodontic infections. J Clin Microbiol 2006; 44:1274-82. [PMID: 16597851 PMCID: PMC1448633 DOI: 10.1128/jcm.44.4.1274-1282.2006] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Members of the domain Archaea, one of the three domains of life, are a highly diverse group of prokaryotes, distinct from bacteria and eukaryotes. Despite their abundance and ubiquity on earth, including their close association with humans, animals, and plants, so far no pathogenic archaea have been described. As some archaea live in close proximity to anaerobic bacteria, for instance, in the human gut system and in periodontal pockets, the aim of our study was to assess whether archaea might possibly be involved in human endodontic infections, which are commonly polymicrobial. We analyzed 20 necrotic uniradicular teeth with radiographic evidence of apical periodontitis and with no previous endodontic treatment. Using real-time quantitative PCR based on the functional gene mcrA (encoding the methyl coenzyme M reductase, specific to methanogenic archaea) and on archaeal 16S rRNA genes, we found five cases to be positive. Direct sequencing of PCR products from both genes showed that the archaeal community was dominated by a Methanobrevibacter oralis-like phylotype. The size of the archaeal population at the diseased sites ranged from 1.3 x 10(5) to 6.8 x 10(5) 16S rRNA gene target molecule numbers and accounted for up to 2.5% of the total prokaryotic community (i.e., bacteria plus archaea). Our findings show that archaea can be intimately connected with infectious diseases and thus support the hypothesis that members of the domain Archaea may have a role as human pathogens.
Collapse
Affiliation(s)
- M E Vianna
- Division of Oral Microbiology and Immunology, University Hospital (RWTH), Pauwelsstrasse 30, D-52057 Aachen, Germany
| | | | | | | |
Collapse
|