The metabolic profile of Aspergillus extracts by HR-MAS NMR Spectroscopy combined with multivariate statistical analysis.

Aspergillus is an ubiquitary fungal genus whose conidia are present in the air we breathe, but does not normally cause illness. In those people with a weakened immune system [1] Aspergillus is a true opportunistic filamentous fungus. Common Aspergillus infections include Invasive Aspergillosis (IA), Allergic BronchoPulmonary Aspergillosis (ABPA) and aspergilloma. Unfortunately, today the overall mortality for aspergillosis in immunosuppressed patients is high, till 60%.[2] This phenomenon is also connected to the resistance of some strains to specific antifungal. In this scenario the importance to know the metabolic content of different isolated Aspergillus strains comes out clearly in order to understand the resistance mechanism to certain drugs. The present work is part of the preliminary stage of the study on the antifungal-resistant Aspergillus. The work is focused on the characterization, based on the metabolic profile, of phenotypes of the isolated Aspergillus species using 1H High Resolution Magic Angle Spinning (HR-MAS) NMR spectroscopy.[3,4] Four different Aspergillus species were studied: A. niger, A. fumigatus, A. flavus and A. terreus. A significative number of replicates of Aspergillus extracts were characterized by conventional 1H HR-MAS spectra. Moreover, in order to discriminate the metabolic profile of each Aspergillus strain, multivariate statistical analysis (PCA, PLS-DA) was also performed on the 1H-NMR data. This combined approach is useful to identify peculiar strain-specific biomarkers. The results show some evidence of metabolic differences in the studied strains.