Banca de DEFESA: MÁRIO TATSUO MAKITA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MÁRIO TATSUO MAKITA
DATA : 25/04/2019
HORA: 09:30
LOCAL: SALÃO VERDE
TÍTULO:

Phenotypic and genotypic identification of Malassezia spp isolated from otitis of dogs and cats and detection of pathogenicity and sensitivity to antifungal in vitro.

PALAVRAS-CHAVES:

Malasseziosis, microbiological diagnosis, fungal infection

PÁGINAS: 72
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
SUBÁREA: Patologia Animal
RESUMO:

The genus Malassezia currently comprises 17 species of lipophilic and lipid-
dependent yeasts. Considered a normal part of the skin microbiota of warm-blooded
vertebrates, including humans, these may also become opportunistic agents in dermatitis
and otitis. Fungal otitis in dogs have been associated with M. pachydermatis, but lipid-
dependent species are also commonly found, indicating a possibility of frequent
misdiagnosis. In the veterinary clinical routine, microscopy of otological samples is
used as an auxiliary tool towards the implementation of an adequate drug therapy. The
aim of this work was the isolation of Malassezia spp. from otitis samples from dogs and
cats, their respective identification at the species level, observe the presence of
Malassezia in pure or co-infections, in vitro detection the main virulence factors
inherent to the genus pathogenicity being produced, and the establishment of a
correlation between the detected virulence factors being produced and the nature of the
infection. A total of 170 samples from the external ear canal of 94 dogs and 11 cats with
clinical otitis were sent to the Laboratory of Pathogenic and Environmental Yeasts,
where they were inoculated in Modified Dixon Agar and Sabouraud Dextrose 2% Agar
supplemented with chloramphenicol. Classical methods allowed for the phenotypic
identification, as recommended by Kurtzman et al. (2011) further corroborated through
proteomic analysis by MALDI-TOF MS and biochemical analysis by VITEK2 ® . For
virulence analysis, protease, phospholipase, lipase, esterase and hemolysin production
were tested. Of the 105 animals, 63% (66) individuals were positive for Malassezia sp.,
as one lipid dependent, and 37% (39) were negative for the genus. The positive and
negative predictive values of the direct exam were 75.58% and 67.19%, respectively.
The sensitivity of the isolation test was 75.58% and the specificity 67.19%. There was
no significant difference between yeast recovery in Sabouraud Dextrose 2% Agar and
Modified Dixon Agar. The identification by mass spectrophotometry had an 82%
accuracy in the identification of the isolates and remaining isolates did not reach the
identification score, whereas VITEK® misidentify all the samples. For the enzymatic
tests, 100% (96) of the samples were positive for the production of proteases and
lipases. Only one sample did not produce phospholipase nor esterase. 89% (86) samples
were hemolysin producers. It was possible to conclude that the use of Modified Dixon
Agar is important in the laboratory routine for microbiological diagnosis of canine and
feline otitis, extending the range of Malassezia species diagnosed. Direct examination
proved to be a good indicator of the presence of yeast, but not enlightening regarding its
involvement in the infection. In addition, these yeasts have high enzymatic activity in
vitro and may be part of the pathogenesis of microbial otitis, even when it is not the
main pathological agent, as in co-infections otitis even with low isolation counts.

Key words: malasseziosis, microbiological diagnosis, fungal infection

MEMBROS DA BANCA:
Presidente - 386849 - FRANCISCO DE ASSIS BARONI
Externo à Instituição - GISELA LARA DA COSTA - FIOCRUZ
Externo à Instituição - REGINA HELENA RUCKERT RAMADINHA