Characterizations of Streptococcus agalactiae from subclinical mastitis cases in dairy cow

Abstract

Abstract Subclinical mastitis (SCM) is a disease that often infects dairy cow, which then reduce milk production. Streptococcus agalactiae is well known as a dominant causative agent of SCM. An experiment to identify S. agalactiae from subclinical mastitis cases in dairy cows has been conducted. These isolates were examined using presumptive S. agalactiae of Christie, Atkins, and Munch-Petersen (CAMP) test and followed by Grouping test to identified it, which was cultured in soft agar (SA) and serum soft agar (SSA) to observed the capability at surface phenotype expression. Haemagglutination test of these isolates were used 1% cow erythrocyte. Fifty-seven positive Gram and negative catalase of cocci bacteria were isolated from the process of identification, of which 34 were CAMP positive. From the grouping test of these, 14 isolates of S. agalactiae Group B (SGB) were identified. Furthermore, 8 isolates are diffuse cultured in SA, while the remain 6 isolates are compact in SSA. Noncapsulated SGB with antigenic side would be expressed as compact culture in SA and SSA. Haemaglutynine (Hn+) property of SGB have a role in adhesive process at epithelial of mamary gland alveolus.