Bacterial adherence in pathogenicity

Escherichia coli adhesins associated with extraintestinal infections such as acute pyelonephritis and neonatal meningitis are carboxyhydrate-binding proteins preferentially located at the tips of pili (fimbriae). Strategies to purify the adhesins prior to their polymerization into the pilus are discussed as a means to obtain structural and functional information concerning adhesin-receptor interactions. Such information is important for the future design of improved receptor analogues. The manner in which structural variation in an adhesin gene may yield antigenic and epitopic binding variants is also discussed. It is suggested that minor differences in the binding pocket of the adhesin may have major consequences on the tropism of the adhering organism. Finally, it is emphasized that bacterial adhesins may also recognize host proteins, and binding to matrix proteins as a means for bacterial attachment is briefly discussed.