Clinical manifestations and outcomes of musculoskeletal nontuberculous mycobacterial infections.

To investigate the clinical manifestations and outcomes of musculoskeletal (MSK) nontuberculous mycobacterium (NTM) infections. This study was a retrospective cohort study using the Siriraj Hospital database from 2005 to 2017. Enrolled were all patients aged 15 or older who had an MSK infection with NTM identified in synovial fluid, pus, or tissue by an acid-fast bacilli stain, culture, or polymerase chain reaction. Of 1529 cases who were diagnosed with NTM infections, 39 (2.6%) had an MSK infection. However, only 28 patients met our inclusion criteria. Their mean age (SD) was 54.1 (16.1) years, and half were male. Of this cohort, 25% had previous musculoskeletal trauma, 18% prior bone and joint surgery, 14% prosthetic joint replacement, and 11% HIV infection. The median symptom duration (IQR) was 16 (37.4) weeks. The most common MSK manifestation was arthritis (61%), followed by osteomyelitis (50%), tenosynovitis (25%), and spondylodiscitis (14%). The most common organism was M. abscessus (18%), and M. kansasii (18%), followed by M. intracellulare (14%), M. marinum (14%), M. fortuitum (7%), and M. haemophilum (7%). In addition to medical treatment, most patients underwent surgery (82%), comprising debridement, osteotomy, prosthesis removal, and amputation, while 18% received only medical treatment. The treatment outcomes were complete recovery in 46%, improvement with some residual disability and deformities in 29%, and death in 3.6%. Musculoskeletal NTM infections were uncommon. Most patients had underlying joint disease or were immunocompromised hosts. Surgical management, as an adjunct to medical therapy, was necessary.