title: Infection of total hip prosthesis by Mycobacterium tuberculosis and Mycobacterium chelonae in a patient with rheumatoid arthritis.
abstract: Atypical mycobacterial infections of the musculoskeletal system are very rare and are generally associated with predisposing factors, such as trauma, use of corticosteroids, or an immunocompromised state. There have only been three reports of Mycobacterium chelonae prosthetic infection of which two cases were associated with total hip arthroplasty and one with total knee arthroplasty and no reports of both Mycobacterium tuberculosis and M. chelonae occurring in the same joint. We report a case of a patient with rheumatoid arthritis treated with low-dose methotrexate (15 mg/week) who developed infection with both M. tuberculosis and M. chelonae after the revision of a prosthetic hip. Joint infections by mycobacteria are clinically indistinguishable from those caused by more common bacterial pathogens and, therefore, diagnosis is often delayed. Recurrent prosthetic hip infections, particularly in immunosuppressive patients, should alert the physician to consider the possibility of both tuberculous and atypical mycobacterial infections. Obtaining appropriate cultures can be critical in making the diagnosis and directing treatment. With the increasing use of immunosuppressive agents, including TNF alpha inhibitors, it is likely that there will be an increase in the number of mycobacterial infections complicating arthroplasties.
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0563, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Brown
authors.forename: Peter
authors.initials: P
authors.lastname: Grubbs
authors.forename: Anne-Barbara
authors.initials: AB
authors.lastname: Mongey
mesh_terms: D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy* / Q000601:surgery; D006622:Hip Prosthesis / Q000382:microbiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis* / Q000209:etiology; D016926:Mycobacterium chelonae / Q000472:pathogenicity*; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity*; D009894:Opportunistic Infections / Q000175:diagnosis* / Q000209:etiology; D014376:Tuberculosis / Q000175:diagnosis* / Q000209:etiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D018501:Antirheumatic Agents; D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha; D008727:Methotrexate