Trial reportScientific reports2018
Tobacco-smoking-related prevalence of methanogens in the oral fluid microbiota.
Trial report in Scientific reports, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It has been retracted, and should not be counted. Cited by 28 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
28 citing papers in PubMed, 47 citations in OpenAlex.
- Methanobrevibacter smithii strain U29 whole genome sequence delineates M. smithii intermediate cell variants.BMC research notes · 2025Article
- Retraction: Tobacco smoking affects the salivary gram-positive bacterial population.Frontiers in public health · 2025Article
- Retraction: Among live and dead bacteria, the optimization of sample collection and processing remains essential in recovering gut microbiota components.Frontiers in microbiology · 2025Article
- Retraction: Deciphering the urinary microbiota repertoire by culturomics reveals mostly anaerobic bacteria from the gut.Frontiers in microbiology · 2025Article
- Review
- The oral microbiome: diversity, biogeography and human health.Nature reviews. Microbiology · 2024Review
- Article
- Review
- Evaluating Alterations of the Oral Microbiome and Its Link to Oral Cancer among Betel Quid Chewers: Prospecting Reversal through Probiotic Intervention.Pathogens (Basel, Switzerland) · 2023Review
- Functional biomes beyond the bacteriome in the oral ecosystem.The Japanese dental science review · 2022Review
- A Non-Invasive Neonatal Signature Predicts Later Development of Atopic Diseases.Journal of clinical medicine · 2022Article
- Bacteria and Methanogens in the Human Microbiome: a Review of Syntrophic Interactions.Microbial ecology · 2022Review
- Introducing clinical nanorachaeaology: Isolation by co-culture ofCurrent research in microbial sciences · 2022Article
- Meta-analyses on the Periodontal Archaeome.Advances in experimental medicine and biology · 2022Review
- MeconialCurrent research in microbial sciences · 2021Article
- Metagenomic analysis of ancient dental calculus reveals unexplored diversity of oral archaeal Methanobrevibacter.Microbiome · 2021Article
- Article
- The Influence of Diet on Oxidative Stress and Inflammation Induced by Bacterial Biofilms in the Human Oral Cavity.Materials (Basel, Switzerland) · 2021Review
- Hydrogen-methane breath testing results influenced by oral hygiene.Scientific reports · 2021Article
- Diversity of Methanogens in Animals' Gut.Microorganisms · 2020Article
Corrections and comments
- Retraction · 2025-02-11Author Unresponsive · Concerns/Issues about Human Subject Welfare · Investigation by Journal/Publisher · Lack of IRB/IACUC Approval and/or Compliance ·
- Retracted
Authors and funding
7 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The oral fluid microbiome comprises an important bacterial diversity, yet the presence of archaea has not been reported so far. In order to quest for the presence of methanogenic archaea (methanogens) in oral fluid, we used a polyphasic approach including PCR-sequencing detection, microscopic observation by fluorescence in-situ hybridization, isolation and culture, molecular identification and genotyping of methanogens in 200 oral fluid specimens. In the presence of negative controls, 64/200 (32%) prospectively analysed oral fluid specimens were PCR-positive for methanogens, all identified as Methanobrevibacter oralis by sequencing. Further, fluorescence in-situ hybridization detected methanogens in 19/48 (39.6%) investigated specimens; with morphology suggesting M. oralis in 10 cases and co-infecting Methanobrevibacter smithii in nine cases. M. oralis was cultured from 46/64 (71.8%) PCR-positive specimens and none of PCR-negative specimens; and one M. smithii isolate was co-cultured with M. oralis in one specimen. Multispacer Sequence Typing found one M. oralis genotype per specimen and a total of five different genotypes with 19/46 (41%) of isolates all belonging to spacer-type four. Statistical analyses showed a significant correlation between the PCR-detection of methanogens in oral fluid and tobacco smoking. These data indicate that M. oralis and M. smithii are oral fluid-borne methanogens in tobacco smokers. Both methanogens could be transmitted during intimate contacts such as mother-to-child contacts and kissing.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.