The Characteristics ofStaphylococcus aureusSmall Colony Variant Isolated from Chronic Mastitis at a Dairy Farm in Yunnan Province, China

Abstract

Staphylococcus aureusis a major causative agent leading to bovine mastitis and has specific phonotypical characteristics including small colony, slow growth, and decreased hemolysis, therefore named as the small colony variants (SCVs). Out of 30 tested samples of the chronicS. aureuscases, one strain of SCVs (S. aureusSCV22) was isolated along with its parental strains (S. aureus11).S. aureusSCV22 showed a slow growth rate when it is compared with the parental strain. However, their resistant patterns were similar. Meanwhile,S. aureusSCV22 depicted the lower rate of apoptosis in bovine mammary epithelial cells. These findings of the present study presented the unique characteristics ofS. aureusSCV22 for the first time in Yunnan province, which provided a prophase foundation for further study about the pathogenesis ofS. aureusSCVs in chronic mastitis.