These three strains also possessed tcpA. TcpA is major subunit of TCP, which plays an important role in the process of establishing an infection of V. cholerae. For example, TCP is involved in colonization on the surface of the human small intestine, via self-aggregation to protect against host defenses and concentrate the secreted CT (Taylor et al., 1987; Ghasemi et al., 2020). This evidence concerns the gene SPINK1 and infection.