Virulence genotypes, antimicrobial susceptibility profiles, and molecular typing of Staphylococcus aureus associated to mastitis in animals coming from the States of Paraná and São Paulo.

• Grant number: 10/10502-5
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2011
• End date: March 31, 2013
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Juliana Rodrigues Pozzi Arcaro
• Grantee: Juliana Rodrigues Pozzi Arcaro
• Host Institution: Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Nova Odessa , SP, Brazil
• City of the host institution: Nova Odessa
• Associated researchers: Antonio Nader Filho ; Claudia Rodrigues Pozzi ; Luiz Francisco Zafalon

Abstract

The purpose of this study is to investigate virulence genotypes, antimicrobial susceptibility profiles, and molecular typing of Staphylococcus aureus isolates associated to mastitis in heifers, after it and lactation. The study will be performed on calves acquired from the state of Paraná - their ages ranging from 15 days to 3 months - which, after being inseminated, around 15 months, they are transferred to milk producers who are part of the project "Balde Cheio". Also, with calves once again acquired in the state of Paraná, from the "Centro Apta Bovinos de Leite", and the "Instituto de Zootecnia", located in Nova Odessa. The milk samples will be taken from black and white Holstein calves and cows in lactation, 60 days before calving, in the day of the birth, 10 days after the calving and during lactation. The samples will be extracted for phenotypic and genotypic identification of Staphylococcus aureus. Antimicrobial susceptibility profiles will be determined by using a disk diffusion method and virulence genes will be screened by PCR. Finally, clonal relationship will be investigated by pulsed field gel electrophoresis (PFGE). The statistical analysis of the microbiological results will be done using the (c²) test for comparison of percentage values (qualitative variables) when n is higher than 5 and the Fischer´s exact test when n is 5 or less. A statistical significance will be defined by a p value d 0.05. The evaluation of discriminatory capacity will be determined according to the numerical index described by Hunter & Gaston (1988). (AU)