Bacterial Adhesin

Bacterial Adhesin Dr. Mohammed Sabri
Adhesins are cell-surface components or appendages of bacteria that facilitate adhesion or adherence to other cells or to surfaces. Adhesins are a type of virulence factor.
Adherence is an essential step in bacterial pathogenesis or infection, required for colonizing a new host.
The first stage of microbial infection is colonization: the establishment of the pathogen at the appropriate portal of entry. Pathogens usually colonize host tissues that are in contact with the external environment. A key step in the host-pathogen interaction is adherence of the pathogen to host surfaces. These surfaces include skin, mucous membranes (oral cavity, nasopharynx, urogenital tract), and deeper tissues (lymphoid tissue, gastric and intestinal epithelia, alveolar lining, endothelial tissue). Microbial adherence factors are called adhesins and can be made from polypeptides (proteins) or polysaccharides (carbohydrates or sugars).
bacterial adherence or attachment to a eucaryotic cell or tissue surface requires the participation of two factors: a receptor and an ligand. The receptors so far defined are usually specific carbohydrate or peptide residues on the eucaryotic cell surface. The bacterial ligand, called an adhesin, is typically a macromolecular component of the bacterial cell surface which interacts with the host cell receptor. Adhesins and receptors usually interact in a complementary and specific fashion.