Shiga toxin-producing Escherichia coli infection: Temporal and quantitative relationships among colonization, toxin production, and systemic disease

Edema disease, a naturally occurring disease of swine caused by Shiga toxin -producing Escherichia coli (STEC), was used as a model for the sequence of events that occur in the pathogenesis of STEC infection. The mean time fro m production of levels of Shiga toxin 2e (Stx2e) detectable in the feces (d ay 1) to the onset of clinical disease (neurologic disturbances or death) w as 5 days (range, 3-9), Bacterial colonization and titers of Stx2e in the i leum peaked at 4 days after inoculation in pigs without signs of clinical d isease and at 6 days after inoculation in clinically affected pigs, Animals with the greatest risk of progressing to clinical disease tended to have t he highest fecal toxin titers (greater than or equal to 1 : 4096), Stx2e wa s detected in the red cell fraction from blood of some pigs showing clinica l signs of edema disease but was not detected in the serum or cerebrospinal fluid.