Escherichia coli is the major aetiological agent of urinary tract infections (UTI). Like diarrhoeagenic strains of E. coli, uropathogenic isolates possess virulence determinants that distinguish them from commensal strains and allow them to produce the clinical manifestations associated with UTI. Several autotransporter proteins have been associated with the ability of E. coli, and other Gram-negative bacteria, to cause disease. Recently, we described the existence within uropathogenic E. coli (UPEC) strains of Sat, a toxin of the serine protease autotransporter of Enterobacteriaceae (SPATE) subfamily. Using features common to proteins secreted via the autotransporter pathway we have identified nine additional autotransporter proteins from the genomic sequence data of UPEC CFT073. Surprisingly, two additional members of the SPATE subfamily were identified. One protein, designated PicU, was homologous to the Pic protein identified in Shigella flexneri and enteroaggregative E. coli. The PicU protein was expressed and investigated for functional activity.

Uropathogenic Escherichia coli is the most common cause of urinary tract infection (UTI). Cystitis in women is by far the most common UTI; pyelonephritis in both sexes and prostatitis in men are more severe but are less frequent complaints. The ability of E. coli to cause UTI is associated with specific virulence determinants, some of which are encoded on pathogenicity islands (PAI). One such PAI (PAI II CFT073 ), of the prototypical uropathogenic E. coli strain CFT073, contains 116 open reading frames, including iron-regulated genes, carbohydrate biosynthetic genes, the serine protease autotransporter picU, a two-partner secretion system, a type I secretion system, mobility genes, and a large number of hypothetical genes. To determine the association of PAI II CFT073 with UTI, PCR was used to examine the prevalence of the five virulence-associated loci among the ECOR collection and a collection of E. coli isolated from patients with cystitis, pyelonephritis, prostatitis, or septicemia. All PAI II CFT073 loci were found to be more prevalent among the B2 phylogenetic group than any other group within the ECOR collection and among invasive prostatitis strains than were cystitis or pyelonephritis strains. These data support the theory that clinical isolates causing prostatitis are more virulent than those producing cystitis or pyelonephritis in women.Urinary tract infections (UTIs) continue to be among the most common extraintestinal diseases. In the United States, UTIs account for 8.7 million annual physician and 2.3 million hospital visits (49). Cystitis in women is by far the most common UTI; pyelonephritis in both sexes and prostatitis in men are more severe but less frequent complaints. Several bacterial species may cause UTIs, but Escherichia coli is by far the most common cause (14), accounting for 50% of all nosocomial UTIs and 90% of infections among ambulatory patients.It is believed that uropathogenic E. coli (UPEC) are adapted to colonizing the urinary tract. The liberation of specific virulence factors may aid attachment to host mucosal tissue, allow evasion of immune defenses, and promote invasion of the normally sterile urinary tract and tissues (14, 15). Among these factors, adhesins, capsule, aerobactin, toxins, and proteases have been described (1,15,36,46). Analysis of the prevalence of virulence factors among commensal E. coli and those causing different UTIs has indicated a greater virulence potential of the disease-causing strains (18,33,46). Moreover, virulence determinants appear to be more prevalent among strains causing invasive disease (46). Interestingly, half of all UPEC isolates possess none, or only one, of the virulence factors characterized thus far. As such, it is reasonable to assume other, as-yet-uncharacterized, bacterial factors may be important in the pathogenesis of UTI (33).The genome sequence of the UPEC strain CFT073 has been determined, and this has allowed the identification of potential virulence genes (54). Several of the genes associated with the acquisition and devel...

Urinary tract infections continue to be among the most common extraintestinal diseases. Cystitis in women is by far the most common urinary tract infection; pyelonephritis in both sexes and prostatitis in men are more severe but less frequent complaints. Escherichia coli is by far the most common cause of urinary tract infection. It is believed that uropathogenic E. coli is adept at colonizing the urinary tract via the production of specific virulence factors. Recently, a novel virulence determinant, Vat, was described for the prototypical uropathogenic E. coli strain CFT073. Vat is a member of the SPATE (serine protease autotransporters of the Enterobacteriaceae) subfamily of the autotransporters. Previously, SPATEs have been described for all pathovars of E. coli, but until recently their presence had been noticeably absent in nonpathogenic E. coli. In this report we describe the prevalence and phylogenetic distribution of the SPATEs among uropathogenic E. coli and the ECOR collection, demonstrating an association between the presence of the SPATEs, including Vat, and uropathogenic E. coli phylogroups. In addition, we describe the distribution of SPATEs among nonpathogenic E. coli.Escherichia coli is the predominant cause of urinary tract infections (UTIs), accounting for 50% of all nosocomial urinary tract infections and 90% of infections among ambulatory patients (6). Among UTIs, cystitis in women is by far the most common, with the more severe complaints pyelonephritis and prostatitis being less frequent (34). The production of specific virulence factors is thought to be necessary for uropathogenic E. coli (UPEC) to colonize the urinary tract (6, 8). These factors include adhesins, capsule, aerobactin, toxins, and proteases, which may aid attachment to host mucosal tissues, allow evasion of immune defenses, and promote invasion of the normally sterile urinary tract and tissues (1,8,24,32). UPEC strains have a greater prevalence of virulence factors than commensal E. coli, with virulence determinants being more prevalent among strains causing invasive rather than noninvasive disease (13,22,32). However, half of all UPEC isolates possess none, or only one, of the virulence factors characterized thus far, and hence other as yet uncharacterized bacterial factors may be important in the pathogenesis of UTI (22).The genome sequence of the UPEC strain CFT073 has been completed, and this has propagated the identification of further potential virulence genes (35). Autotransporters are one category of secreted proteins implicated in the virulence of UPEC (17,18). Members of the serine protease autotransporters of the Enterobacteriaceae (SPATE) family are proteins from E. coli and Shigella spp. which, like the immunoglobulin A1 (IgA1) proteases and Hap autotransporters of Neisseria and Haemophilus spp