Comparison between osteoarticular tuberculosis and nontuberculous mycobacterial infection: a retrospective observational cohort study.

Background: Osteoarticular mycobacterial infections significantly impact patient health by causing severe joint and bone diseases. However, clinical experience in diagnosis and treatment remains limited.

Objectives: We investigated the clinical characteristics and prognosis of patients with osteoarticular mycobacterial infection.

Methods: We retrospectively enrolled 74 adult patients diagnosed with osteoarticular mycobacterial infection, including 57 (77%) with tuberculosis (TB) and 17 (23%) with non-tuberculous mycobacteria (NTM) infection, between January 2009 and January 2023 from a tertiary hospital in Korea. Osteoarticular mycobacterial infection was defined as the presence of osteoarticular infection, including prosthetic joint infection, diagnosed using clinical and radiological findings, and aspirate or tissue culture positive or polymerase chain reaction positive for Mycobacterium tuberculosis complex or NTM.

Results: Several differences were observed in the predisposing factors, affected sites and multifocal infections between the osteoarticular TB and NTM infection groups. The proportion of disseminated infection in patients with TB was higher than that in those with NTM infection (40% vs. 6%, p = .008). The positivity rate of acid-fast bacilli stain, mycobacterial culture, molecular testing and histological examination in all patients was 34%, 89%, 79% and 51%, respectively. Culture-positive or PCR-positive specimens from another site (respiratory specimens, pleural fluid, urine or blood) were collected from 22 patients (30%). Anti-mycobacterial therapy combined with surgical treatment was performed in 77% of all follow-up patients, and clinical failure occurred in 19%.

Conclusions: These findings suggest that, given the differences in optimal treatments, using multiple diagnostic modalities to detect microbiological evidence for discriminating NTM infection from TB is essential.