CONICET | Buscador de Institutos y Recursos Humanos

Staphylococcus aureus and coagulase-negative staphylococci (CNS) are important causes of intramammary infectionin dairy cattle, and their ability to produce biofilm is considered an important virulence property in the pathogenesisof mastitis. However, the published date on mechanisms and factors involved in infection persistence in the mammarygland remains unclear. The aim of this study was to investigate whether the main Staphylococcus species involved inbovine intramammary infections possess specific characteristics that promote colonization of the udder. We evaluated thebiofilm-forming ability and distribution of adhesion- and biofilm-associated genes of Staphylococcus spp. isolated frombovine mastitis infected animals in Argentinean dairy farms. For this purpose, the phenotypic biofilm formation ability of209 Staphylococcus spp. from bovine mastitis was investigated. All isolates produced biofilm in vitro, being 35,0% and45,0% of the 127 S. aureus or 51,0% and 29,0% of the 82 CNS strong and moderate biofilm producers respectively. AllS. aureus samples were PCR-positive for icaA, icaD, clfA, clfB and fnbpA genes, 76.3% were positive for fnbpB geneand 11.0% were positive for bap gene. In CNS isolates, the positive rates for icaA and icaD were 73.2%, while for clfA,clfB, fnbpA fnbpB and bap genes the percentage were lower. The results demonstrate that in Staphylococcus spp. biofilmformation, the polysaccharide and the adhesion- and biofilm-associated genes are of overall importance on bovine mastitisin Argentina. Therefore, future works should focus on these pathogenic specific factors for the development of moreeffective therapies of control, being essential to consider the ability of isolates to produce biofilm.