Microbiota profiling from biopsied tissues in complex infections: a diagnostic and prognostic analysis through metagenomic next-generation sequencing.

Background: Infectious diseases that require tissue biopsy are usually more difficult to diagnose through conventional microbiological tests (CMT), and knowledge of the infection microbiota pattern from biopsied tissues remains incomplete. Our study aimed to investigate the diagnostic and prognostic value of metagenomic next-generation sequencing (mNGS), characterize the microbiota profile from biopsied tissues, and examine its relationship with clinical outcomes.

Methods: This retrospective cohort study included 110 patients who underwent tissue biopsy and sent both mNGS and CMT due to suspected complex infection. Microbiota patterns were illustrated via unsupervised hierarchical clustering analysis. Multivariate regression analysis was used to investigate the effect measures.

Results: The sensitivity of mNGS was significantly higher than that of CMT regarding bacteria (87.23% 40.43%, P=0.01), viruses (100% 5.56%, P<0.001), and fungi (87.5% 28.6%, P=0.04). Polymicrobial infection accounted for 45.2% (33/73) of the infection samples. In skeletal articular biopsied tissues, Staphylococcus presented the highest mean abundance among different species of bacteria (21.2% of all bacterial reads, standard deviation (SD) 38.9). Anaerobic bacteria (24.0%, SD 25.9) represented the most common bacteria in biopsied tissue from the lung or mediastinum. The presence of gram-negative bacteria (adjusted OR 5.21, 95% CI 1.39-19.43, P=0.01), Enterobacteriaceae (adjusted OR 5.71, 95% CI 1.17-28.03, P=0.03) and Staphylococcus (adjusted OR 8.64, 95% CI 1.95-38.34, P=0.005) was associated with an increased risk of treatment failure. Early mNGS sampling within 7 days after admission was associated with a significantly decreased risk of all-cause mortality (HR 0.18, 95% CI 0.04-0.94; P=0.04), treatment failure (OR 0.17, 95% CI 0.05-0.66; P=0.01), and increased probability of clinical resolution (OR 3.03, 95% CI 1.24-7.40; P=0.01).

Conclusion: mNGS demonstrates significant diagnostic and prognostic efficacy in patients undergoing tissue biopsy for suspected complex infections. The presence of Gram-negative bacteria, Enterobacteriaceae, and Staphylococcus is associated with a higher probability of treatment failure, which underscores the advantage of using mNGS to guide more aggressive antibiotic strategies.