Research of genes icaA, icaD and bap bacterial intercellular adhesion and biofilm formation by Staphylococcus aureus and Staphylococcus coagulase-negative isolated from bovine mastitis

Abstract

Milk represents an important sector of worldwide economy. In Brazil, milk industry has also a social relevance; generating millions of jobs by about a million farms. However, mastitis is still an obstacle for dairy farming despite the high number of researches for its diagnosis and control. It is an infectious process of mammary gland, characterized by clinical and subclinical cases, caused by physiological, traumatic, allergic, metabolic, psychological, and/or infectious processes. In the infectious cases, there are many species of pathogens involved, such as Staphylococcus aureus (S. aureus) and coagulase-negative Staphylococcus (CNS) commonly. There are many virulence factors related to these pathogens, one of them is the production of biofilms. The aim of the present study is to investigate the presence of icaA, icaD and bap genes that are generally associated with intercellular adhesion and biofilm formation, and with the persistence of intramammary infection, high severity of clinical cases, and somatic cell count increase (SCC/mL milk) in subclinical cases. A hundred strains of S. aureus and 100 strains of CNS isolated from cases of clinical and subclinical mastitis in dairy herds of different properties of Sao Paulo State will be evaluated. Genes for production of biofilm will be searched by Polymerase Chain Reaction (PCR) and phenotypic characterization will be done by Congo Red Agar (CRA). The purpose of this study is to contribute for a better understanding of the evolution of mastitis caused by S. aureus and CNS, associated with virulence factors.