Characterization and Investigation of Staphylococcus aureus zfb Isolates from Bovine Mastitis

Abstract:

A Staphylococcus aureus strain, designated zfb, was isolated from a clinical bovine mastitis case of a dairy cow. Staphylococcus aureus zfb can have resistance to methicillin and no lipase contrast by ATCC 25923. The production of the capsule was assessed by the diffuse colonial morphology in serumsoft agar. A mouse infection model was used to determine the LD50 and the invasiveness of SA zfb. The LD50 of SA 25923 to experimental mice was 10-2.5/mL, and the LD50 of SA zfb to experimental mice was 10-4.33/mL. The purpose to detect characteristics of SA zfb makes it an interesting candidate for the preparation and assay of an avirulent mutants against staphylococcal infections and further investigate on pathogenic mechanism.

Key words:Staphylococcus aureus, Beta hemolysin, LD50