E.coli is an impoant causative agent of pyelonephritis in man. The propey that helps the bacteria in this is most likely to be:-

Adhesive propey of E.coli helps the bacteria in this case. Option 1 Adhesins: E. coli organisms possess numerous highly specialized adhesins. These adhesins include: (a) CFA-I,II,III (b) Aggregative adherence fimbriae (AAF I,II,III) (c) Bundle-forming pili (Bfp) (d) Intimin (e) P pili(binds to P blood group antigens) (f) Ipa (invasion plasmid antigen) protein (g) Dr fimbriae (bind to Dr blood group antigens). All these adhesins facilitate firm adhesion of E. coli to the gastrointestinal or urinary tract mucosa, thereby preventing the bacteria being eliminated by the flushing action of voided urine or intestinal motility. Option 2 Enterotoxins are impoant virulent factors of diarrhogenic E. coli. Three distinct types of E. coli enterotoxins include : (a) Shiga toxins (Stx-1, Stx-2) (b) heat-stable toxins (STa and STb) (c) heat labilet oxins (LT-I and LT-II). Option 3 Hemolysins are considered impoant in the pathogenesis of disease caused by uropathogenic strains of E. coli. Option 4 Hydrophilic capsular K antigens protect E. coli from phagocytosis, which repel the hydrophobic phagocytic cell surface. The capsular antigens interfere with the binding of antibodies to the bacteria.