Metagenomic Next-Generation Sequencing Profiling of Primary versus Iatrogenic Osteoarticular Infections: Unveiling Distinct Pathogen Spectra and Diagnostic Implications

Abstract Objective To evaluate the diagnostic performance of metagenomic next-generation sequencing (mNGS) versus microbial culture in primary osteoarticular infection (POI) and iatrogenic osteoarticular infection (IOI), and to analyze pathogen spectrum differences and clinical implications. Methods Ninety-two patients with confirmed osteoarticular infection (POI, n=42; IOI, n=50) were retrospectively analyzed. All specimens were tested using both mNGS and conventional culture. The pathogen detection rates, pathogen spectrum composition, detection of mixed infections, and concordance of results between the two methods were compared. Results mNGS demonstrated a significantly higher overall detection rate than culture (72.83% vs. 43.48%; P < 0.001), particularly in IOI (78.00% vs. 34.00%; P < 0.001). Pathogen profiling showed predominance of Staphylococcus aureus in POI, whereas IOI exhibited greater microbial diversity with increased detection of Staphylococcus epidermidis (31.03%) and anaerobes (13.79%). Polymicrobial infections were more frequently identified by mNGS (14.13% vs. 4.35% by culture; P = 0.024), primarily in the IOI group. Concordance between mNGS and culture was substantial in POI (κ = 0.66; 95% CI: 0.42–0.89) but only slight in IOI (κ = 0.12; 95% CI: −0.12 to 0.35), largely attributable to the high rate of mNGS-exclusive positives in IOI (48.00%). Conclusion mNGS improves pathogen detection in osteoarticular infections, especially in IOI where it identifies complex and polymicrobial infections more effectively than culture, providing critical support for guiding antimicrobial therapy.