{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T04:59:54Z","timestamp":1790312394773,"version":"4.1.0"},"reference-count":26,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Osteoarticular\n                      <jats:italic>Mycobacterium avium<\/jats:italic>\n                      complex (MAC) infection is uncommon and can resemble inflammatory arthritis during immunosuppression.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case description<\/jats:title>\n                    <jats:p>A 52-year-old woman with an erosive seronegative rheumatoid arthritis phenotype and overlap autoimmune features developed progressive polyarticular swelling, wrist tenosynovitis, hip effusions, and low-back pain after cumulative immunosuppression. Investigations showed macrocytic anemia, lymphopenia, pan-hypogammaglobulinemia, marked B-cell depletion without anti-CD20 exposure, and cytomegalovirus DNAemia. Pre-treatment mNGS reported MAC-spectrum signals in hip, wrist, and elbow aspirates, including 355 right-hip reads. A separate pathogen-targeted joint-fluid sequencing report, with no anatomical site stated, detected MAC complex (116,330 normalized sequences; assay-estimated 10\u2075 copies\/mL). Neither result was interpreted as organism burden. No tissue histopathology, dedicated mycobacterial culture, or phenotypic susceptibility testing was performed. The working diagnosis was multisite sequencing-supported probable multifocal osteoarticular MAC infection without culture confirmation. Several interventions began concurrently. Selected follow-up MR images showed persistent destructive wrist disease and residual joint or periarticular fluid, but no standardized imaging or microbiological response endpoint was available.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>In atypical arthritis progressing during immunosuppression, infection-focused sampling should precede further escalation. mNGS can provide an etiologic clue, but culture, histopathology, targeted testing, and longitudinal reassessment remain essential.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmed.2026.1954797","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T04:26:19Z","timestamp":1790310379000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Sequencing-supported probable osteoarticular Mycobacterium avium complex infection in rheumatoid arthritis"],"prefix":"10.3389","volume":"13","author":[{"given":"Jing","family":"Zhang","sequence":"first","affiliation":[{"name":"Department of Rheumatology and Immunology, Peking University International Hospital","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lina","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Rheumatology and Immunology, Peking University International Hospital","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sheng-Guang","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Rheumatology and Immunology, Peking University International Hospital","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ji","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Rheumatology and Immunology, Peking University International 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