Percorrer por autor "Relvas, Ana Sofia Taveira"
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- Characterisation of volatilomics in fungal samples extracted from the homes of patients with hypersensitivity pneumonitisPublication . Relvas, Ana Sofia Taveira; Rufo, João; Vieira, MónicaA cell-mediated hypersensitive response to inhaled environmental antigens results in hypersensitivity pneumonitis (HP), an interstitial lung disease. It is the third most frequent ILD and is more common in workers exposed to mold and microbiological pollutants. Clinical and immunological evaluations are used in the diagnosis process. The phenotypical identification of fungi species is crucial for differentiating these microorganisms, involving the observation of colonial morphological characteristics. However, this method has limitations such as the time required for cultivation and the need for highly qualified professionals for this purpose. Produced by bacteria, fungus, and other microorganisms, volatile organic compounds (VOCs) are part of the metabolism of these microbes and have an important role in many fields. Those compounds include some functional groups such as alcohols, ketones, benzenoids, carboxylic acids and aldehydes. In this project, the goal consisted of identifying distinct VOC profiles from samples of fungi collected in homes of patients with HP. The volatile organic compound profiles from five fungi collected in the houses of patients with hypersensitivity pneumonitis (Penicillium sp., Alternaria sp., Gliocladium virens, Aspergillus flavus and Aspergillus niger) were evaluated using e-nose and the findings were compared with phenotypic identification based on mycological methods. Principal component analysis (PCA) was used for dimensionality reduction and hierarchical clustering was used to group related profiles into nested structures. Chi-square tests were used to compare proportions between clusters, and ROC curves were created using the data to assess the profile's sensitivity and specificity. Results of the e-nose analysis showed a significant differentiation in the profiles of volatile organic compounds after 48 hours of inoculation. The VOC profiles consisted essentially in alkanes, ketones, alcohols, aromatic hydrocarbons and aldehydes. Also, the methodology was effective in clearly differentiating the Penicillium sp. from other samples. All fungi apart from Alternaria sp. were clearly differentiated from the control group. The findings also enabled the creation of a possible model to predict fungi exposure at home, verified by the high area under the ROC curve. The current study has shown that the electronic nose has a lot of promise as a quick and efficient method for distinguishing various fungi species.