Gene expression profile in patients inoculated with Escherichia coli 83972

Mucosal surfaces provide ideal living conditions for the normal flora but paradoxically, they also serve as attack sites for numerous bacterial pathogens that cause extensive morbidity and mortality. Understanding this dichotomy is critical for efforts to selectively target and remove pathogens without disturbing the commensal flora or its protective effects. The complex nature of disease predicts that virulence is multifaceted and that pathogens need multiple virulence factors to initiate tissue attack, disrupt immune homeostasis and create symptoms and pathology. The urinary tract supports ABU; a commensal-like state, which has been shown to prevent super-infection with more virulent strains. To reproduce this protective effect, we have established a protocol to create ABU, by inoculation with the ABU strain E. coli 83972. The therapeutic efficacy and safety of this procedure has been documented in placebo-controlled studies in patients with incomplete bladder voiding. Genome sequencing of E. coli 83972 has revealed a general “loss of virulence” phenotype, which includes fimbrial genes. E. coli 83972 lacks functional P or type 1 fimbriae, due to attenuating point mutations in the papG adhesin gene and a large, inactivating deletion in the fim gene cluster. Both fimbrial types have been proposed to enhance bacterial persistence in the urinary tract. In an attempt to increase the efficiency of E. coli 83972 inoculation and extend its use to include UTI-prone patients with complete bladder voiding, we restored P- and type 1-fimbrial expression and addressed how fimbriae affect the gene expression in inoculated human hosts. Prior to inoculation, patients were treated with antibiotics to sterilize their urine. E. coli was cultured overnight (16 h) in lysogeny broth, cells were harvested by centrifugation and re-suspended in PBS to a concentration of 10^5 cfu/ml. Patients were inoculated with 30 ml of the solution through a catheter, which was then removed. Blood samples were collected prior to inoculation, 3, 24 and 48 hours and at 1 and 2 weeks after inoculation.