title: Molecular Typing of Mastitis-Causing Staphylococcus aureus Isolated from Heifers and Cows.
abstract: Staphylococcus aureus is among the main etiologic agents of bovine mastitis. A total of 83 isolates of S. aureus from mammary glands of primiparous heifers were collected in the prepartum, calving and during lactation. For lactating cows, a total of  27 isolates of S. aureus from mammary glands were collected during lactation. The samples were taken in two dairy farms located in Sao Paulo State, Brazil. The highest frequency of S. aureus isolation in heifers was at the end of lactation. Strains were typified through Pulsed-field gel electrophoresis (PFGE) and grouped according to patterns of restriction enzyme SmaI. PFGE generated seven clonal profiles that were grouped into three different lineages, with the LA lineage being predominant and identified in heifers, as well as in the cows from the two regions studied. It was concluded that the cows showed a significant source of dispersion of S. aureus. At the first lactation the heifers were infected by the same clonal profiles of S. aureus which were isolated from multiparous lactating cows. The heifers were infected during milking over the months of lactation.
authors: Institute of Animal Science, Dairy Cattle Center, Nova Odessa 13460, São Paulo, Brazil. livia_cast@yahoo.com.br.
authors: Lívia
authors: L
authors: Castelani
authors: Aline Franciele Silva
authors: AF
authors: Santos
authors: Mariana
authors: M
authors: Dos Santos Miranda
authors: Luiz Francisco
authors: LF
authors: Zafalon
authors: Claudia Rodrigues
authors: CR
authors: Pozzi
authors: Juliana Rodrigues Pozzi
authors: JR
authors: Arcaro