Banca de QUALIFICAÇÃO: MARIO TATSUO MAKITA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIO TATSUO MAKITA
DATE: 12/12/2024
TIME: 15:00
LOCAL: sala 74 IV
TITLE:

Analysis of the ear microbiome in dogs with otitis externa and comparison with bacterial culture diagnosis.

KEY WORDS:

Microbiological diagnosis, bacterial culture, otological disease, veterinary dermatology.

PAGES: 100
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

"Canine otitis externa is the most common ear disease in dogs, affecting about 20% of the population. For the infection to establish, it is essential that there is some imbalance in the ear microenvironment. The indiscriminate use of antimicrobials in the treatment of otitis contributes to the selection of resistant strains and complicates treatment. The present study aimed to analyze the microbiota in dogs with otitis externa in Brazil and compare it with the data obtained from bacterial cultures requested for diagnosis. Samples were collected from 48 dogs with otitis externa during consultations at private clinics, and their samples had already been collected for diagnostic purposes, totaling swabs from 106 ears. The samples were collected in duplicate, one for bacterial culture and one for DNA extraction. The swabs were inoculated onto 5% Sheep Blood Agar and Eosin-Methylene Blue Agar. After purification, the isolates were identified using phenotypic methods, including MALDI-TOF MS. A total of 125 isolates were obtained from the cultures, identified from 33 bacterial genera/species. In 20 samples, there was no bacterial growth after 48 hours. After sample identification, antibiogram tests were performed using the disc diffusion method and interpreted according to the CLSI VET01S (2024) and BRCAST (14.0, 2024) documents. The DNA extraction product from the second swab was stored at -20ºC until sent for sequencing. The products were sent to Novogene Corporation Inc. in Sacramento, CA, for quality analysis and sequencing. In total, 42 samples met the quality criteria and were sequenced. Based on the analysis of the distribution of the 10 most prevalent agents, the genera Staphylococcus and Corynebacterium were the most prominent within the otological populations. Beta-diversity analysis indicated a correlation between at least two groups with a similar microbial community. One group included the Shih-Tzu, Pug, and Beagle breeds, while the other group included the Pug, French Bulldog, Lhasa Apso, and German Spitz breeds. Data from a single animal over time were also analyzed, with samples collected at three distinct time points, allowing the observation of the natural evolution of the ear microbiome over a short period. Forty samples with culture and sequencing results were analyzed. Comparing culture results with sequencing, it was observed that 4 (7.27%) bacterial isolates did not appear in sequencing. In 17 (30.91%) samples, the culture result was consistent with the most abundant genus in the microbiome, and in 34 (61.82%) cultures, the culture result did not match the microorganism most abundant in the sequencing. Of the latter, in 27 (49.09%) cases, sequencing showed that more abundant cultivable genera existed than those found in the culture. In 16 (29.09%) samples, the most abundant bacteria were anaerobic. In half of the cases, there were populations of more abundant cultivable bacteria that were not isolated, raising questions about the ability of cultures to detect the actual infectious agent of otitis and whether they are reliable for therapeutic analysis via antibiogram. Thus, we can conclude that bacterial cultures of otitis do not always detect the most abundant bacterial population.

COMMITTEE MEMBERS:
Interna - 2212438 - MILIANE MOREIRA SOARES DE SOUZA
Externa ao Programa - 1609810 - LIDIANE DE CASTRO SOARES - UFRRJExterna à Instituição - CÁSSIA COUTO DA MOTTA