Molecular Characterization of Staphylococcus aureus Isolates Implicated in Bovine Mastitis

Abstract

Staphylococcus aureus is a well-known contagious and opportunistic pathogen responsible for bovine mastitis worldwide, and in Malaysia, the sequence types (STs) of these isolates associated with bovine mastitis had not been previously characterized. This study therefore aimed to characterize S. aureus isolates from bovine mastitis cases in Malaysian dairy herds, using isolates recovered following standard procedures and analyzed via multi-locus sequence typing with a boiling method. A total of ten isolates were analyzed, revealing six distinct sequence types: ST97 (CC97) was the most prevalent (n=4), followed by ST1 (CC1) (n=2), and then ST221 (CC5) (n=1), ST1496 (CC1) (n=1), ST4427 (CC97) (n=1), and ST2125 (CC1) (n=1). Notably, ST2125 and ST1496 were identified for the first time in association with bovine mastitis. The most widespread S. aureus ST linked to subclinical mastitis in Malaysia was ST97, and the molecular epidemiology of this ST, along with the other STs identified, was compared to S. aureus STs reported globally.