Banca de DEFESA: MARCIA GABRIELE DE SOUZA JIMENEZ
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARCIA GABRIELE DE SOUZA JIMENEZ
DATE: 21/12/2022
TIME: 14:00
LOCAL: Link de acesso para videoconferência: meet.google.com/gvn-nkso-ukm
TITLE:
MOLECULAR IDENTIFICATION, CHARACTERIZATION OF VIRULENCE FACTOR AND ANTIFUNGAL SUSCEPTIBILITY PROFILING OF ISOLATES OF Trichosporon spp. OBTAINED FROM PATIENTS WITH WHITE PIEDRA
KEY WORDS:
Trichosporon spp., genotyping, virulence, cellular stress, antifungal susceptibility, white piedra.
PAGES: 123
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:
Yeasts belonging to the genus Trichosporon emerge as emerging pathogens with high rates of
morbidity and mortality. Primarily, Trichosporon species are etiological agents of white piedra, a
fungal infection characterized by nodules adhered to the extrafollicular region of the hair shaft.
However, in recent decades, Trichosporon spp. have been considered an opportunistic pathogen
responsible for severe infections, mainly in immunocompromised patients with hematological
diseases. The objectives of this study were to carry out the molecular identification (IGS1 region of
the rDNA) of Trichosporon spp. obtained from white piedra, as well as to determine the in vitro
expression of virulence factors, including: DNAses, hemolysins and phospholipases activity, ability
to adhere to epithelial cells, cell surface hydrophobicity, melanin production and biofilm
production, in addition to to evaluate fungal growth in the presence of cellular stressors. The
antifungal susceptibility profile of clinical isolates of Trichosporon spp. results were compared to
strains obtained from systemic infection. We identified 4 T. asahii isolates, 17 T. inkin isolates, 2 T.
faecale and 2 T. asteroides isolates. Phylogenetic analysis revealed a higher degree of genetic
relatedness (high bootstrap value) between T. asahii, T. asteroides and T. faecale, with T. inkin
being considered the least closely related species. T. inkin isolates were more prevalent in clinical
samples obtained from patients with white piedra, in addition to having a greater ability to adhere to
human buccal epithelial cells. The T. asahii isolates showed higher capacity for biofilm formation,
cell surface hydrophobicity and hemolytic index. All evaluated isolates were able to produce
hemolysins and DNAses, whereas melanin production on Niger Seed Agar was not detected.
Phospholipase production was negative for all tested isolates, except for two strains of T. inkin,
which showed a high Pz value (low enzyme production). Several isolates evaluated showed
minimal inhibitory concentrations and high epidemiological cut-off values, with a tendency to
multidrug resistance to azoles (ketoconazole, itraconazole and fluconazole) and amphotericin B.
Although the present study included few isolates of T. asahii, it was observed that this species, in
general, stands out in the expression of virulence factors and resistance to antifungal agents,
reinforcing its importance in invasive trichosporonosis.
COMMITTEE MEMBERS:
Externo à Instituição - EDELTRUDES DE OLIVEIRA LIMA - UFPB
Presidente - 1715308 - GUILHERME MARANHAO CHAVES
Externa ao Programa - 2121234 - VANIA SOUSA ANDRADE - null