The human respiratory, digestive and urogenital tracts are the prime sites of bacterial colonization. Together they offer an area of 300–400 square meters constituting major sites for bacterial adherence (Ribet and Cossart, 2015). Therefore, the present study used epithelial cell lines originating from pharyngeal, gastric, intestinal and cervical tissues and 25 different bacterial strains to study the early host response upon bacterial colonization.