flexneri infections (Fasano et al., 1995). The ShET-2 toxin is encoded by the sen gene located on the 140-MDa invasiveness plasmid Nivolumab in vitro (Fasano et al., 1995). This toxin has been reported in different species of Shigella causing traveller’s diarrhoea (Vargas et al., 1999) and increases transepithelial conductance in an

in vitro model, although the relevance of the toxin in clinical disease is unknown (Nataro et al., 1995). The enteroaggregative heat stable toxin 1 (EAST-1) toxin is encoded by the astA gene (Savarino et al., 1996). This toxin is thought to play a role in EAEC pathogenicity. Epidemiological studies have associated this gene with E. coli pathotypes other than EAEC such as ETEC and EHEC and with other bacterial genera including Salmonella (Vargas et al., 1999; Paiva de Sousa & Dubreuil, 2001). EAST-1 is a 38 amino-acid peptide, and the astA gene is detected in commensal and diarrheic E. coli strains (Kaper et al., 2004). EAST-1 induces the production of Ku-0059436 concentration high levels of cGMP in the cell, inhibiting the Na/Cl

cotransport system and reducing the absorption of electrolytes and water from the intestine at villus tips (Dreyfus & Robertson, 1984), resulting in an elevated secretion of Cl− and water in crypt cells. However, the role of this toxin in the development of diarrhoea has yet to be defined. AggR is a transcriptional factor encoded by the aggR gene, which controls expression of not only adherence factors (AAFI and AAFII) but also chromosomal genes (Nataro et al., 1994). Relationships between susceptibility to several antimicrobial agents and virulence have been demonstrated. Thus, exposure to subinhibitory concentrations

of quinolones Morin Hydrate induces a loss of VFs contained within PAIs (Soto et al., 2006). The transference of VFs contained in PAIs and other mobile genetic elements among different species plays an important role in bacterial pathogenicity, and thus the aim of this study was to determine the presence and spread of the genes encoding the ShET-1, ShET-2 and EAST-1 toxins and AggR factor in E. coli strains causing bacteraemia and their possible relationship with both clinical and microbiological characteristics in order to elucidate whether these enterotoxins could play a role in the pathogenicity of these infectious diseases. A total of 174 E. coli blood isolates collected from patients with bacteraemia in the Hospital Clinic of Barcelona during 2002 were included. The uropathogenic E. coli (UPEC) clinical strain HC91255 was used as a control for biofilm assay.