Emerging and cryptic Aspergillus species isolated from hospitalized patients with underlying primary immunodeficiencies

Abstract Poster session 2 September 22 2022 12:30 PM - 1:30 PM Objectives Although Aspergillus fumigatus is the most common etiologic agent of invasive aspergillosis multiple poorly recognized non-fumigatus species have been reported from patients with iatrogenic immunosuppression and individuals with underlying primary immunodeficiencies (PIDs). The species-level identification of causative agents and the determination of antifungal susceptibility patterns can play significant roles in the outcome of aspergillosis. In the current study we aimed to investigate the frequency of non-fumigatus Aspergillus species isolated from hospitalized patients with PIDs at National Institutes of Health (NIH) Clinical Center Bethesda MD USA. Methods In a prospective study between January 2019 and December 2021 a total of 279 Aspergillus species were isolated from NIH hospitalized patients with underlying PIDs. The species-level identification of each isolate was attempted by colony morphology microscopic characteristics matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and PCR-sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA the β-tubulin and Calmodulin (CaM) genes. Results Overall members of Aspergillus section Fumigati were the most common group (71%) followed by section Veriscolores (7%) section Usti (4%) section Tanneri (4%) section Terrei (3%) section Nigri (3%) and section Nidulantes (3%). Aspergillus species belong to sections Falvi Clavati Flavipedes and Circumdati were less frequent and each counted for only 1% of the total isolates identified. Notably cryptic and non-fumigatus members of section Fumigati comprised only 12% of the isolates including A. felis A. udagawae A. lentulus A. thermomutatus A. viridinutans, and A. pseudoviridinutans while A. fumigatus was the dominant species (88%). MALDI-TOF assay was able to properly differentiate sections of Aspergillus from each other. However PCR-sequencing of the β-tubulin gene was the most reliable target to separate the cryptic species of each section. Conclusion Our study shows that frequency of rare and cryptic Aspergillus species that primarily affect patients with PIDs may significantly differ from those with acquired immunodeficiencies. Due to their lower susceptibility to available antifungal agents than A. fumigatus correct and prompt identification at the species level is critical for appropriate therapy to improve patient outcomes. In addition DNA sequence-based species identification targeting β-tubulin gene is more accurate than ITS and CaM genes and using MALDI-TOF to differentiate the emerging and cryptic Aspergillus species.