Performance of Metagenomic Next-Generation Sequencing of Cell-Free DNA From Vitreous and Aqueous Humor for Diagnoses of Intraocular Infections

Background Delayed diagnosis and improper therapy for intraocular infections usually result in poor prognosis. Due to limitations of conventional culture and polymerase chain reaction methods, most causative pathogens cannot be identified from vitreous humor (VH) or aqueous humor (AH) samples with limited volume.Methods Patients with suspected intraocular infections were enrolled from January 2019 to August 2021. Metagenomic next-generation sequencing (mNGS) was used to detected causative pathogens.Results This multicenter prospective study enrolled 488 patients, from whom VH (152) and AH (336) samples were respectively collected and analyzed using mNGS of cell-free DNA (cfDNA). Taking final comprehensive clinical diagnosis as the gold standard, there were 39 patients with indefinite final diagnoses, whereas 288 and 161 patients were diagnosed as definite infectious and noninfectious diseases, respectively. Based on clinical adjudication, the sensitivity (92.2%) and total coincidence rate (81.3%) of mNGS using VH samples were slightly higher than those of mNGS using AH samples (85.4% and 75.4%, respectively).Conclusions Using mNGS of cfDNA, an era with clinical experience for more rapid, independent, and impartial diagnosis of bacterial and other intraocular infections can be expected. Our findings provide solid evidence for the feasibility of metagenomic next-generation sequencing (mNGS) using cell-free DNA (cfDNA) in the identification of intraocular infections, especially the trace pathogens, and highlight the advantages of mNGS using cfDNA.