To investigate the disruption of the brush border of polarized epithelial cells, SL1344 wild-type (WT), sipA, sopA, sopB, sopE, sopE2mutant strains, M712 strain, which lacks the five mentioned effector proteins, and their complemented derivates were used for invasion experiments in MDCK Pf and C2bbe1 cell lines, the later were also used to evaluate the disruption of the trans-epithelial electrical resistance (TEER) by the Salmonella infection.