The complexity of invasive fungal diseases in the intensive care unit: evaluation of metagenomic next-generation sequencing

Background: In the intensive care unit (ICU), a subset of adult individuals who are non-neutropenic and lack conventional host risk factors frequently develop fungal infections, which constitute a major mortality risk in this population. This patient group has received limited attention to date, and research on diagnostic approaches remains insufficient. This research looks into whether metagenomic next-generation sequencing (mNGS) could be used to diagnose this group of people. Methods: We performed a retrospective analysis of 106 individuals with invasive fungal infections between July 2022 and February 2025. These patients were divided into two groups: immunocompetent and immunocompromised. Demographic and clinical characteristics were analyzed and compared between the two groups. The diagnostic value of mNGS was carefully assessed, and its diagnostic performance was contrasted with that of conventional microbiological tests (CMTs). In addition, the impact of mNGS results from different specimen types on clinical management and antifungal treatment decisions was summarized. Results: . mNGS showed a distinct superiority in identifying uncommon pathogens and mixed infections, with its total positive rate markedly exceeding that of CMTs. mNGS results led to beneficial modifications in clinical management for 75 patients (70.75%). The clinical impact varied by specimen type, including bronchoalveolar lavage fluid (BALF; 61 cases), blood (14 cases), and other sterile body fluids (31 cases), with blood specimens yielding the least clinical benefit. Conclusion: In the ICU, a substantial number of invasive fungal infections occur among patients without classical host risk factors. mNGS offers substantial benefits in identifying fungal pathogens and mixed infections, hence enhancing the diagnostic efficacy of invasive fungal diseases (IFDs). The extent of clinical benefit is affected by the kind of specimen provided for testing.