The present invention describes a novel mechanism of adhesion by flagellated Gram-negative bacteria such as enterotoxigenic Escherichia coli (ETEC), where the bacteria secretes a protein, EtpA which binds to the conserved region of the flagellin protein located at the tip of the flagella. The present invention also discloses that EtpA-mediated interaction and intestinal colonization require interaction with flagellin. Also disclosed herein is a vaccine composition that can be used for either active or passive immunization of mammals for the prevention or treatment of infections caused by flagellated Gram-negative bacteria.
