Bacterial infection, which basically starts when the microorganism binds to certain host cells, is a multi-factorial process that can be subdivided into distinct stages. To initiate infection, pathogens must first be able to colonize an appropriate host target tissue. Colonization begins
with attachment. The primary stage of infection is modulated by specific molecules on both the pathogens and the host cells. The bacterial factors are often called adhesins, and the host cell factors are receptors. The initial contact between adhesins and receptors always involves biophysical and biochemical interactions. Although adhesin proteins and bacterial lectins are the most common functional elements of adhesins, the carbohydrate content of receptors is
their most functional part. Blocking the primary stage of infection may be the most effective strategy to prevent bacterial infections. Although adhesin-based vaccine studies have been demonstrated to protect against infections, the large number of bacterial adhesin structures
would necessitate the development of a different vaccine for each bacteria. In contrast, most of the adhesin receptors on eukaryotic cells are rich in carbohydrates, and many of these carbohydrate
moieties are rich in sialic acid, although some of them are not well defined. Thus receptor carbohydrate moieties and their sialic acid content may be key targets in this strategy.

Keywords: Adhesins, Bacterial - physiology, Bacterial Vaccines - isolation & purification, Gram-Negative Bacteria - pathogenicity, Gram-Negative Bacteria - physiology, Gram-Positive Bacteria - immunology, Gram-Positive Bacteria - pathogenicity, Gram-Positive Bacteria - physiology, N-Acetylneuraminic Acid - physiology, Receptors, Immunologic - physiology