The potential of metagenomic next-generation sequencing in the diagnosis of fracture-related infection: a retrospective study

Abstract

Background Diagnosis of infective pathogen could be challenging in fracture-related infection (FRI). Metagenomic next-generation sequencing (mNGS) is a new approach to identify the organism in bone infection disease. We aimed to evaluate the accuracy of mNGS in determining the causative organisms of FRI. Methods From January 2021 to June 2023, a total of 105 cases with suspected FRI in our hospital were enrolled. Samples for mNGS, culture, and histopathological tests were collected surgically or by aspiration biopsy. mNGS was performed for diagnosis. Sensitivity and specificity were calculated for mNGS and culture test, using histopathological results in conjunction with FRI criteria. Results According to FRI criteria, 96 of the 105 cases had infection, and 9 were classified in the aseptic group. Specificity of mNGS was 88.9% (95% confidence interval [95% CI], 51.8–99.7%), sensitivity was 90.6% (95% CI, 82.9–95.2%), positive predictive value (PPV) was 98.9% (95% CI, 93.8–99.9%), and negative predictive value (NPV) was 47.1% (95% CI, 26.2–69.0%). Specificity of culture was 100% (95% CI, 66.4–100%), sensitivity was 50% (95% CI, 39.6–60.4%), PPV was 100% (95% CI, 92.6–100%), and NPV was 15.8% (95% CI, 7.5–27.9%). mNGS was more sensitive than culture (χ༒=9.931, P = 0.001), whereas the specificity of mNGS and culture was similar (P > 0.05). A total of 81.2% (39/48) of culture-negative patients had positive results on mNGS. Soft tissue specimen without pus was a risk factor for the negative result of mNGS (χ༒=5.693, P = 0.017). In FRI cases, open fracture was a risk factor for polymicrobial infection (χ༒=11.482, P = 0.001). Conclusions mNGS offers higher sensitivity for diagnosis and pathogen detection of FRI compared with microbiological culture. We believe that application of mNGS in the field of FRI would benefit more patients.