*4.1.4 S and F1C fimbriae*

S and F1C fimbriae are also involved in the urinary tract infection process. Both fimbriae are shown to have very related biogenesis genes however they have different adhesin alleles. They exhibit binding to epithelial and endothelial cells from the lower urinary tract and kidneys in humans [25, 26]. S fimbriae binds to sialic acid epitopes which are present in renal sialylated lipoproteins. Also, they particularly are also responsible for other extraintestinal infections such as sepsis, meningitis apart from UTI because they may promote the dissemination of bacteria within the host tissues. As per various pooled studies, F1C fimbriae are more usually seen in strains from pyelonephritis and cystitis patients than fecal strains used as controls [27]. Furthermore, experiments conducted in a try to know their exact role in UTI have not been reported clearly but in strain CFT073, in which type 1 and P fimbriae encoding genes have been inactivated, F1C fimbriae were expressed at elevated levels demonstrating a synchronize fimbrial expression in UPEC [28].
