{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T10:11:02Z","timestamp":1779358262196,"version":"3.51.4"},"reference-count":25,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T00:00:00Z","timestamp":1779321600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background and Clinical Significance:\u00a0Tannerella forsythia is a Gram-negative, anaerobic bacterium primarily associated with severe periodontal disease. Extraoral infections are extremely rare, and the presence of Tannerella forsythia in synovial fluid has not been reported previously. Case Presentation: We report a case of a 60-year-old female with grade IV primary osteoarthritis referred for dental evaluation. Clinical and radiographic examination revealed stage IV generalized periodontitis. Subgingival plaque samples were collected after non-surgical periodontal therapy and analyzed using a semi-quantitative real-time PCR targeting the 16S rRNA gene. During planned knee surgery, synovial fluid was obtained and processed using the same molecular protocol. PCR analysis of samples from the deepest periodontal pockets and synovial fluid confirmed the presence of Tannerella forsythia, demonstrating its potential dissemination from oral to joint tissues. The postoperative course was uneventful, with no signs of joint infection. Conclusions: To the best of our knowledge, this is the first reported detection of Tannerella forsythia in the synovial fluid of a patient with osteoarthritis, supporting the possibility of oral\u2013joint microbial translocation. This finding should be interpreted with caution, as the detection of bacterial DNA does not indicate viability or causative involvement. More research is necessary to clarify the mechanisms underlying this association.<\/jats:p>","DOI":"10.3390\/diagnostics16101565","type":"journal-article","created":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T09:29:58Z","timestamp":1779355798000},"page":"1565","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Molecular Detection of Tannerella forsythia in the Synovial Fluid of a Patient with Knee Osteoarthritis: A Case Report Suggesting Oral\u2013Joint Translocation"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-3351-9260","authenticated-orcid":false,"given":"Ivana","family":"Mili\u0107","sequence":"first","affiliation":[{"name":"Dental Polyclinic Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6569-9287","authenticated-orcid":false,"given":"Mihovil","family":"Ple\u010dko","sequence":"additional","affiliation":[{"name":"Department for Orthopaedic Surgery, University Hospital Center Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4766-048X","authenticated-orcid":false,"given":"Domagoj","family":"Vra\u017ei\u0107","sequence":"additional","affiliation":[{"name":"Department of Periodontology, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Domagoj","family":"Delimar","sequence":"additional","affiliation":[{"name":"Department for Orthopaedic Surgery, University Hospital Center Zagreb, 10000 Zagreb, Croatia"},{"name":"Department for Orthopaedic Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7683-6563","authenticated-orcid":false,"given":"Ivan","family":"Puhar","sequence":"additional","affiliation":[{"name":"Department of Periodontology, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1038\/s41584-020-0447-8","article-title":"Core and Adjunctive Interventions for Osteoarthritis: Efficacy and Models for Implementation","volume":"16","author":"Bowden","year":"2020","journal-title":"Nat. Rev. Rheumatol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1186\/ar2655","article-title":"Developments in the scientific understanding of osteoarthritis","volume":"11","author":"Abramson","year":"2009","journal-title":"Arthritis Res. Ther."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Xie, X., Zhang, K., Li, Y., Li, Y., Li, X., Lin, Y., Huang, L., and Tian, G. (2025). Global, Regional, and National Burden of Osteoarthritis from 1990 to 2021 and Projections to 2035: A Cross-Sectional Study for the Global Burden of Disease Study 2021. PLoS ONE, 20.","DOI":"10.1371\/journal.pone.0324296"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Terkawi, M.A., Ebata, T., Yokota, S., Takahashi, D., Endo, T., Matsumae, G., Shimizu, T., Kadoya, K., and Iwasaki, N. (2022). Low-Grade Inflammation in the Pathogenesis of Osteoarthritis: Cellular and Molecular Mechanisms and Strategies for Future Therapeutic Intervention. Biomedicines, 10.","DOI":"10.3390\/biomedicines10051109"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1004","DOI":"10.1111\/j.1600-051X.2009.01496.x","article-title":"Detection of periodontal bacterial DNA in serum and synovial fluid in refractory rheumatoid arthritis patients","volume":"36","author":"Little","year":"2009","journal-title":"J. Clin. Periodontol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1097\/RHU.0b013e3182500c95","article-title":"Identification of oral bacterial DNA in synovial fluid of patients with arthritis with native and failed prosthetic joints","volume":"18","author":"Chakaki","year":"2012","journal-title":"J. Clin. Rheumatol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3480","DOI":"10.4103\/jfmpc.jfmpc_759_19","article-title":"Red complex: Polymicrobial conglomerate in oral flora: A review","volume":"8","author":"Mohanty","year":"2019","journal-title":"J. Fam. Med. Prim. Care"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Yin, K.J., Huang, J.X., Wang, P., Yang, X.K., Tao, S.S., Li, H.M., Ni, J., and Pan, H.-F. (2022). No genetic causal association between periodontitis and arthritis: A bidirectional two-sample Mendelian randomization analysis. Front. Immunol., 13.","DOI":"10.3389\/fimmu.2022.808832"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Astuti, L., Masulili, S.L.C., Gunardi, I., Sulijaya, B., and Soeroso, Y. (2025). Periodontal pathogens correlate with rheumatoid arthritis disease parameters: A systematic review based on clinical studies. Dent. J., 13.","DOI":"10.3390\/dj13050214"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Guo, X., Wang, S., Ding, J., Liu, W., Xu, J., Wang, M., Sun, H., Ma, Y., Liu, W., and Zhang, L. (2025). Periodontopathic bacteria in rheumatoid arthritis pathogenesis: Bridging clinical associations to molecular mechanisms. Front. Immunol., 16.","DOI":"10.3389\/fimmu.2025.1681037"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1007\/s40496-020-00254-6","article-title":"Persistence of Tannerella forsythia and Fusobacterium nucleatum in dental plaque: A strategic alliance","volume":"7","author":"Sharma","year":"2020","journal-title":"Curr. Oral Health Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1074","DOI":"10.1111\/jcpe.12470","article-title":"Relationship between periodontitis-associated subgingival microbiota and clinical inflammation by 16S pyrosequencing","volume":"42","author":"Novoa","year":"2015","journal-title":"J. Clin. Periodontol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3944","DOI":"10.1128\/JCM.43.8.3944-3955.2005","article-title":"Identification of candidate periodontal pathogens and beneficial species by quantitative 16S clonal analysis","volume":"43","author":"Kumar","year":"2005","journal-title":"J. Clin. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1061","DOI":"10.1111\/j.1600-051X.2004.00616.x","article-title":"Quantitative real-time polymerase chain reaction versus culture: A comparison between two methods for the detection and quantification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in subgingival plaque samples","volume":"31","author":"Lau","year":"2004","journal-title":"J. Clin. Periodontol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1046\/j.1365-2591.2002.00485.x","article-title":"Direct amplification of rRNA gene sequences for identification of selected oral pathogens in root canal infections","volume":"35","author":"Siqueira","year":"2002","journal-title":"Int. Endod. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"6975","DOI":"10.2147\/IDR.S434494","article-title":"Lung abscess caused by Tannerella forsythia infection: A case report","volume":"16","author":"Lv","year":"2023","journal-title":"Infect. Drug Resist."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Oogai, Y., Tanaka, Y., and Nakata, M. (2025). Microbial Coaggregation in the Oral Cavity: Molecular Interactions and Current Insights. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms262110552"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3496","DOI":"10.3390\/cimb44080241","article-title":"Classifying integrated signature molecules in macrophages of rheumatoid arthritis, osteoarthritis, and periodontal disease: An omics-based study","volume":"44","author":"Sao","year":"2022","journal-title":"Curr. Issues Mol. Biol."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Cecoro, G., Annunziata, M., Iuorio, M.T., Nastri, L., and Guida, L. (2020). Periodontitis, low-grade inflammation and systemic health: A scoping review. Medicina, 56.","DOI":"10.3390\/medicina56060272"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ji, R., Zhao, X., Chen, Z., Ge, Y., Wu, Z., and Wang, X. (2025). Hepatocyte Growth Factor Differentially Modulates Oral Microbiota in Early vs. Late Experimental Periodontitis. Biology, 14.","DOI":"10.3390\/biology14101393"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Chen, Z., Zhong, Y., Chen, L., Liu, W., Lin, C., Chen, Y., and Wang, X. (2025). HGF Aggravated Periodontitis-Associated Gut Barrier and Microbial Dysfunction: Implications for Oral\u2013Gut Axis Regulation. Biology, 14.","DOI":"10.3390\/biology14050496"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1441","DOI":"10.1016\/j.joca.2010.08.016","article-title":"Circulating levels of IL-6 and TNF-\u03b1 are associated with knee radiographic osteoarthritis and knee cartilage loss in older adults","volume":"18","author":"Stannus","year":"2010","journal-title":"Osteoarthr. Cartil."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1186\/s13027-019-0220-2","article-title":"The role of Tannerella forsythia and Porphyromonas gingivalis in pathogenesis of esophageal cancer","volume":"14","author":"Malinowski","year":"2019","journal-title":"Infect. Agents Cancer"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e01391","DOI":"10.1002\/rcr2.1391","article-title":"Lung abscess caused by the anaerobic pathogen Tannerella forsythia","volume":"12","author":"Miao","year":"2024","journal-title":"Respirol. Case Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.jdsr.2022.12.001","article-title":"Integrative analysis of gene and protein expression in atherosclerosis-related pathways modulated by periodontal pathogens: Systematic review","volume":"59","year":"2023","journal-title":"Jpn. Dent. Sci. Rev."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/10\/1565\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T09:52:57Z","timestamp":1779357177000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/10\/1565"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,21]]},"references-count":25,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["diagnostics16101565"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16101565","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,21]]}}}