Gene expression profile in patients inoculated with E. coli 83972

Urinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation, in which the contrasting effects of pathogens and commensals on host tissues are clearly displayed. While virulent Escherichia coli cause severe, potentially life-threatening disease by breaking the inertia of the mucosal barrier and infecting the kidneys, the most common outcome of bacteriuria is an asymptomatic carrier state resembling commensalism at other mucosal sites. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease associated responses in the host. To address this question, we examined the effects of asymptomatic bacterial carriage on host gene expression. Therapeutic urinary tract inoculation with the prototype ABU strain E. coli 83972 is a safe alternative approach in patients with therapy-resistant recurrent UTI. The strain establishes persistent bacteriuria, protecting patients against super-infection with more virulent strains. Using this protocol, we examined if the establishment of asymptomatic bacterial carriage alters host gene expression. After antibiotic treatment to remove prior infection, patients were inoculated with E. coli 83972 through a catheter. Blood samples were obtained before and 24 h after inoculation.