{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T06:56:17Z","timestamp":1778655377716,"version":"3.51.4"},"reference-count":49,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2021,10,4]],"date-time":"2021-10-04T00:00:00Z","timestamp":1633305600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Innovation and Technology Ministry, Hungary","award":["Scientific Excellence Program TKP2020-NKA-17"],"award-info":[{"award-number":["Scientific Excellence Program TKP2020-NKA-17"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Genes"],"abstract":"<jats:p>Regular exercise can upgrade the efficiency of the immune system and beneficially alter the composition of the gastro-intestinal microbiome. We tested the hypothesis that active athletes have a more diverse microbiome than sedentary subjects, which could provide better protection against COVID-19 during infection. Twenty active competing athletes (CA) (16 male and 4 females of the national first and second leagues), aged 24.15 \u00b1 4.7 years, and 20 sedentary subjects (SED) (15 male and 5 females), aged 27.75 \u00b1 7.5 years, who had been diagnosed as positive for COVID-19 by a PCR test, served as subjects for the study. Fecal samples collected five to eight days after diagnosis and three weeks after a negative COVID-19 PCR test were used for microbiome analysis. Except for two individuals, all subjects reported very mild and\/or mild symptoms of COVID-19 and stayed at home under quarantine. Significant differences were not found in the bacterial flora of trained and untrained subjects. On the other hand, during COVID-19 infection, at the phylum level, the relative abundance of Bacteroidetes was elevated during COVID-19 compared to the level measured three weeks after a negative PCR test (p &lt; 0.05) when all subjects were included in the statistical analysis. Since it is known that Bacteroidetes can suppress toll-like receptor 4 and ACE2-dependent signaling, thus enhancing resistance against pro-inflammatory cytokines, it is suggested that Bacteroidetes provide protection against severe COVID-19 infection. There is no difference in the microbiome bacterial flora of trained and untrained subjects during and after a mild level of COVID-19 infection.<\/jats:p>","DOI":"10.3390\/genes12101577","type":"journal-article","created":{"date-parts":[[2021,10,4]],"date-time":"2021-10-04T09:24:15Z","timestamp":1633339455000},"page":"1577","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["COVID-19 Infection Alters the Microbiome: Elite Athletes and Sedentary Patients Have Similar Bacterial Flora"],"prefix":"10.3390","volume":"12","author":[{"given":"Gergely","family":"Babszky","sequence":"first","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ferenc","family":"Torma","sequence":"additional","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dora","family":"Aczel","sequence":"additional","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6120-3384","authenticated-orcid":false,"given":"Peter","family":"Bakonyi","sequence":"additional","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zoltan","family":"Gombos","sequence":"additional","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Janos","family":"Feher","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Sapienza University of Rome, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D\u00f3ra","family":"Szab\u00f3","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Semmelweis University, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bal\u00e1zs","family":"Ligeti","sequence":"additional","affiliation":[{"name":"Faculty of Information Technology and Bionics, P\u00e1zm\u00e1ny P\u00e9ter Catholic University, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"S\u00e1ndor","family":"Pongor","sequence":"additional","affiliation":[{"name":"Faculty of Information Technology and Bionics, P\u00e1zm\u00e1ny P\u00e9ter Catholic University, 1123 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laszlo","family":"Balogh","sequence":"additional","affiliation":[{"name":"Institute of Sport Science, University of Debrecen, 4000 Debrecen, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anik\u00f3","family":"P\u00f3sa","sequence":"additional","affiliation":[{"name":"Interdisciplinary Excellence Center, Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, 6700 Szeged, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1297-6804","authenticated-orcid":false,"given":"Zsolt","family":"Radak","sequence":"additional","affiliation":[{"name":"Research Institute of Sport Science, University of Physical Education, 1123 Budapest, Hungary"},{"name":"Faculty of Sport Sciences, Waseda University, Tokorozawa 2-579-15, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1186\/s13578-020-00404-4","article-title":"SARS-CoV-2 and COVID-19: The most important research questions","volume":"10","author":"Yuen","year":"2020","journal-title":"Cell Biosci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"565","DOI":"10.1016\/S0140-6736(20)30251-8","article-title":"Genomic characterisation and epidemiology of 2019 novel coronavirus: Implications for virus origins and receptor binding","volume":"395","author":"Lu","year":"2020","journal-title":"Lancet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"50","DOI":"10.3389\/fmicb.2019.00050","article-title":"Severe Acute Respiratory Syndrome Coronavirus Viroporin 3a Activates the NLRP3 Inflammasome","volume":"10","author":"Chen","year":"2019","journal-title":"Front. 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