Taxonomía y filogenia de aislados clínicos y ambientales de penicillium y talaromyces

Identifier:  TDX:2822

Handle: https://hdl.handle.net/20.500.11797/TDX2822

Authors:  Guevara Suárez, Marcela Isabel

Abstract:
The penicilia are a group of mycromicetes with a wide distribution both in natural habitats and in environments influenced by human presence, where Penicilium and Talaromyces are some of the most important genera. The main objective of this thesis was to contribute to a better understanding of these genera by exploring the diversity of the species from different substrates. A total of 314 isolates were obtained (118 from clinical origin and 196 from environmental origin, including soil and dung samples). The identification of the isolates was carried out with the phylogenetic analysis of a fragment of the β-tubulin gene. The characterization and proposal of new taxa was performed using a polyphasic identification that included phylogenetic analyses with multiple loci (ITS, β-tubulin, and/or rpb2, calmodulin) and the phenotypic characterization (physiological, macroscopic and microscopic characteristics). Additionally, we evaluated the in vitro antifungal susceptibility of the most frequent species from clinical isolates against the main drugs. In summary, we identified a total of 263 strains within Penicilium genus, 45 in Talaromyces, 2 in Rasamsonia, and 4 isolates associated to two new genera within Aspergillaceae family. The most representative sections of Penicilium from the clinical isolates were Chrysogena and Citrina, while in Talaromyces, it was section Talaromyces. Moreover, four new species have been proposed for this last genus. The in vitro antifungal susceptibility profiles showed a good terbinafine and equinocandines activity against the evaluated species of Penicilium and Talaromyces, while amphotericin B showed an intermediate antifungal activity. Regarding the isolates from environmental origin, a total of 50 species of penicilia were identified, from which 13 new species were proposed (9 from Penicillium; 4 from Talaromyces) as were the two new genera Penicillago and Pseudopenicillium.