Characterization of a putative virulence island in the chromosome of uropathogenic Escherichia coli possessing a gene encoding a uropathogenic-specific protein

This study was initiated to search for a homologue of the Vibrio cholerae z ot gene in uropathogenic Escherichia coli (UPEC) using a specific DNA probe . The faint signal obtained at low stringency with some UPEC strains associ ated with prostatitis cases prompted us to examine UPEC strains by PCR usin g primers designed from the conserved regions of the proteins of the Zot gr oup of putative NTPases containing the classical NTP binding motif. This le d to the discovery of a DNA fragment in UPEC strains which hybridized with a probe designed from the PCR. Further analysis of this DNA fragment reveal ed an ORF which was designated as uropathogenic specific protein (Usp). The gene encoding Usp was 1038 bp long and codes for 346 amino acids with an a ppropriate SD sequence. Upstream and downstream analysis of usp revealed mo tifs of prokaryotic consensus promoters and three small ORFs with SDs and r ibosome binding sites transcribed in the same direction of usp. The proximi ty of these set of genes in a specific area of the bacterial chromosome res embling a block of genes preferentially associated with UPEC coupled with t he presence of a motif matching that of a Tn3 transposon family lead us to believe that this could be an hitherto unknown pathogenicity island. (C) 20 00 Academic Press.