Molecular epidemiology and virulence factors of Staphylococcus aureus associated to bovine mastitis in dairy herds from São Paulo and Pernambuco state.

Author(s)

Franklin Geronimo Bispo Santos

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2009-07-31

Examining board members

Elizabeth Oliveira da Costa Freitas Guimarães; Nilson Roberti Benites; Eduardo Harry Birgel Junior; Elisabete Jose Vicente; Luiz Francisco Zafalon

• Advisor: Elizabeth Oliveira da Costa Freitas Guimarães

Abstract

A total of 107 S. aureus isolated from bovine milk, udder skin, milkers and milking machine, from São Paulo and Pernambuco herds was typed by molecular techniques. PCR-RFLP coa gene and PCR spa gene distinguished six amplicons. All strains amplified coa, spa, icaA genes and, 69% produced in vitro glucose-induced biofilm. PFGE identified 31 pulsotypes, 12 lineages. One of the lineages was predominantly isolated (P<0.0001) and widely disseminated. A same pulsotype was isolated from clinical and, subclinical mastitis as well as from carriers. There was genetic heterogeneity among isolates from the herds. Strains from human and animal origin were genetically different. Few isolates from milk, milking machine and udder skin showed similar pulsotype. An extramammary strain, 77% of the milk isolates and, 99% of the S. aureus isolated from carriers produced biofilm. It was not detected any correlation between SCC and biofilm production. The successive isolation during more than 16 days of a same pulsotype from the asymptomatic glands characterized the carrier status. (AU)