Specificity of immunomodulator secretion in urinary samples in response to infection by alpha-hemolysin and CNF1 bearing uropathogenic Escherichia coli.

Escherichia coli are the most common etiological agents of urinary tract infections (UTIs). Uropathogenic E. coli (UPECs) produce specific toxins including the cytotoxic necrotizing factor-1 (CNF1) and the alpha-hemolysin (alpha-Hly). CNF1 triggers, through Rho protein activation, a specific gene response of host cells, which results in the production for instance of interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and the macrophage inflammatory protein-3alpha (MIP-3alpha). The alpha hemolysin alpha-Hly also triggers the production of inflammatory mediators. Cnf1 is always associated with alpha-hly in a pathogenicity island conserved among UPECs. Using two complementary approaches we have investigated whether alpha-hly and cnf1 bearing UPECs are associated with a specific type of UTI both in term of pathology and host response. Here we report that UPECs bearing alpha-hly/cnf1 have a prevalence of 50% in UPECs isolated from hemorrhagic UTIs, as compared to 30% in the overall UPEC population. In addition, we observed that MCP-1, and IL-8 to a lower extent, is produced in urine at higher concentrations in UTIs caused by UPECs carrying alpha-hly/cnf1.