Study of the molecular diversity of strains of Staphylococcus aureus isolated from bovine mastitis

Abstract

Mastitis is considered the disease of greatest impact in the global dairy industry and in Brazil, production losses between 12 and 15% are estimated, which represents about three billion liters of milk / year. However, despite adoption of the current management practices to minimize the occurrence of mastitis, results are not satisfactory for the control of mastitis by Staphylococcus aureus, the major causative agent of bovine mastitis. Besides veterinary importance, there are also implications for human health due to the potential for zoonotic spread of S. aureus by unpasteurized dairy products, and due to the extensive use of antibiotics in the treatment and control of disease. Molecular epidemiology studies are important in the understanding of the genetic diversity among causative agents of mastitis in a region or country, the distribution of pathogen groups within and between herds and their phylogenetic relationship. Typing by sequencing single locus (SPA typing) and multilocus (MLST) has been successfully used to investigate the population structure of pathogenic bacteria, especially S. aureus. Both methods are suitable for epidemiological studies since they provide information that can be compared between different laboratories. Comparison of the profile (sequence type ST) among S. aureus from different sources (animals and properties) is useful in the understanding of the role of these hosts as reservoirs for pathogenic strains and of the epidemiological aspects involved in the transmission of this pathogen. This project aims to understand the genetic diversity of S. aureus strains isolated from bovine mastitis, identify possible new ST profiles, and to know the distribution of ST in space and time. (AU)