Feasibility of mitochondrial single nucleotide polymorphisms to detect and identify Aspergillus fumigatus in clinical samples

Abstract

Invasive aspergillosis (IA) is a concerning fungal infection among immunocompromised patients due to the poor outcomes in its treatment related with the delay in an accurate diagnosis. Therefore, this study aimed to select informative mitochondrial single nucleotide polymorphism (SNP) markers suitable for detection and identification of Aspergillus fumigatus in clinical specimens. Four mitochondrial SNP markers were selected (Cox_488, CytB_246, Nad1_802, and NC_171) and tested on clinical and environmental strains of Fumigati and non-Fumigati Aspergillus species (n=105). These markers were tested on clinical samples (n=37) obtained from patients with aspergillosis. The Cox_488 SNP was detected in all clinical samples, whereas complete profiles detecting all 4 SNPs were only obtained from 6 samples (1 lung biopsy, 2 abscesses, and 3 bronchoalveolar lavages) from patients with a probable or proven Aspergillus infection. The mitSNApfu approach based on mitochondrial markers constitutes a new and promising diagnostic approach that was applied successfully on clinical specimens from patients with proven or probable IA. Nevertheless, the assay requires further optimization (in respect to extraction procedures) and clinical validation to allow its application in routine diagnostics.

Keywords: Fungal infection; Mini-sequencing; Mitochondrial DNA; Non-culture based diagnostic; Nucleic acid based diagnostic; Single nucleotide polymorphism (SNP).