A microbiologist wants to develop a vaccine for prevention of attachment of diarrheagenic E. coli to the specific receptors in the GI tract. All of the following would be appropriate vaccine candidates except:

All of the following among the given options would be appropriate vaccine candidates except P-pili as they have role in uropathogenic E.coli, not diarrheagenic E.coli. Option 1, 2, 3 - P-PILI: Have no role in the attachment of diarrheagenic E.coli to the GI receptors. Have role in Adherence of uropathogenic E.coli to urothelial cells. - CFA 1 and CS 2 - Colonization factor antigens of ETEC (diarrheagenic E.coli ). Option 4 - Fimbriae promote virulence of E. coli. - K88 and K99 antigens in E. coli strains causing diarrhea in animals or CFA in ETEC are examples of such fimbriae.