Species distribution and clinical significance of filamentous fungi detected from respiratory specimens before and after matrix-assisted laser desorption/ionization time-of-flight mass spectrometry implementation.
Abstract
Background
The clinical significance of filamentous fungi detected from respiratory specimens uncertain in routine clinical practice, particularly for non-Aspergillus. We evaluated longitudinal species distribution and clinical correlates after implementation of MALDI-TOF MS.
Methods
This single-center retrospective study included 585 patients with a filamentous-fungus-positive respiratory specimen from 2010 through 2024; the most recent positive specimen per patient was retained. Independent pre-implementation (2010-2018) and post-implementation (2019-2024) periods were compared. Medical records of 228 post-implementation patients were reviewed. Isolates were classified as Aspergillus or non-Aspergillus filamentous fungi. Cases treated with systemic antifungal agents were classified as clinically treated infection and untreated cases as colonization. Clinical characteristics were compared between the two groups.
Results
Overall, 307 isolates (52.5 %) were Aspergillus, 130 (22.2 %) were identified non-Aspergillus filamentous fungi, and 148 (25.3 %) remained unidentified. From the pre-implementation to post-implementation period, identified non-Aspergillus filamentous fungi increased from 17.6 % to 29.4 % (p = 0.001), while unidentified isolates decreased from 28.6 % to 20.2 % (p = 0.023). In the post-implementation cohort, 58 patients had clinically treated infection and 170 had colonization. Multivariable analysis showed that non-Aspergillus detection was negatively associated with clinically treatable infection (OR 0.268, 95 % CI 0.121-0.565), whereas corticosteroid or other immunosuppressant use was positively associated (OR 3.300, 95 % CI 1.597-6.974).
Conclusions
MALDI-TOF MS implementation was associated with fewer unidentified isolates and greater recognition of non-Aspergillus filamentous fungi. When filamentous fungi are detected from respiratory specimens, infection should be assessed by considering fungal species, host factors, and clinical presentation.