Banca de QUALIFICAÇÃO: AMANDA THAÍS FERREIRA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : AMANDA THAÍS FERREIRA SILVA
DATE: 02/08/2023
TIME: 09:00
LOCAL: Videoconferência (via Google Meet)
TITLE:

Epidemiological study and economic impact of bovine mastitis caused by strains of multidrug-resistant Staphylococcus aureus in the State of Pernambuco, Brazil

 

KEY WORDS:

Staphylococcus. Mastitis. Multi-drug resistance. Epidemiology. Economics.

PAGES: 92
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SUMMARY:

The aim of this study was to investigate the prevalence, to determine the risk factors associated with subclinical mastitis caused by multidrug-resistant Staphylococcus (S.) aureus (MDRSA) isolates, and to evaluate the economic impact of subclinical mastitis caused by Staphylococcus spp. and Mammaliicoccus spp. on the economic return in the state of Pernambuco (PE), in the northeastern region of Brazil. A total of 2,444 milk samples, 40 milking utensil swabs, five bulk tank milk samples, and 22 milker swabs (11 nasal and 11 hand swabs) were collected from five dairy farms located in the Agreste region of PE. A total of 315 isolates of Staphylococcus spp. and Mammaliicoccus spp. were identified by MALDI-TOF MS, including 191 S. aureus, 117 non-aureus Staphylococcus, and seven Mammaliicoccus sciuri. Among the S. aureus isolates, 188 were obtained from milk samples, one from a tank milk sample, and two from milking utensils. PCR was used for the detection of resistance genes blaZ, mecA, and mecC, and the Disk Diffusion technique was employed for antimicrobial resistance testing and screening of MDRSA isolates. Fourteen MDRSA isolates were detected (twelve from milk samples, one from a tank milk sample, and one from a milking utensil). In these multidrug-resistant isolates, the presence of efflux pump genes (norA, norC, msrA, and tet38) and biofilm formation genes (bap, icaA, and icaD) was investigated, along with an analysis of biofilm production capacity. Additionally, PFGE and MLST techniques were used to investigate the genetic correlation of these isolates, identifying the clonal complexes CC97 (ST126) and CC1 (ST7440). A logistic regression analysis (SAS Institute) was performed to study the risk factors associated with subclinical mastitis caused by MDRSA, and it was observed that these isolates were more likely to be exclusive to a specific herd. Furthermore, both multiparous and primiparous cows had similar chances of developing subclinical mastitis caused by MDRSA. For the economic impact analysis, linear regression (SAS Institute) was used with data from 342 lactating cows, including 155 cows as a negative control (155 healthy quarters), and 187 cows with subclinical mastitis caused by Staphylococcus and Mammaliicoccus (257 infected quarters). The results showed that the infection by Staphylococcus and Mammaliicoccus resulted in decreased milk production, increased SCC, and reduced economic return for the dairy farms. These findings emphasize the importance of epidemiological studies and economic analysis of mastitis, providing valuable insights for the development of targeted strategies for prevention and control of the infection.

COMMITTEE MEMBERS:
Presidente - RINALDO APARECIDO MOTA
Interno - JOSE WILTON PINHEIRO JUNIOR
Externa ao Programa - 1289130 - ERIKA FERNANDA TORRES SAMICO FERNANDES CAVALCANTI - UFRPEExterno à Instituição - HELIO LANGONI - UNESP
Externa à Instituição - POLLYANNE RAYSA FERNANDES DE OLIVEIRA