CFB and infection: The analysis of virulence factors revealed that the majority of the strains (96%) amplified the following virulence genes: fbsA, fbsB, bibA, cfb, and cyl, which play a role in the stages of intramammary infection caused by S. agalactiae, such as adhesion (bibA), invasion and colonization (fbsA and fbsB), and infection (cfb and cyl).