Down-regulation of the kps region 1 capsular assembly operon following attachment of Escherichia coli type 1 fimbriae to D-mannose receptors.

A differential-display PCR procedure identified the capsular assembly gene kpsD after Escherichia coli type 1 fimbrial binding to mannose-coated Sepharose beads. Limiting-dilution reverse-transcribed PCRs confirmed down-regulation of the kpsD gene, and Northern blot and lacZ fusion analyses showed down-regulation of the kpsFEDUCS region 1 operon. KpsD protein levels fell, and an agglutination test showed less K capsular antigen on the surface following the bacterial ligand-receptor interaction. These data show that binding of type 1 fimbriae (pili) to d-mannose receptors triggers a cross talk that leads to down-regulation of the capsule assembly region 1 operon in uropathogenic E. coli.