Escherichia coli as a probiotic?

The influence of oral treatment with a suspension of non-pathogenic Escherichia coli cells (commercially available as: Symbioflor II) on the morphological composition of the gut microflora and on the systemic humoral immune response (the IgG-, IgA- and IgM-isotype) against the bacterial cells in the Symbioflor II preparation was measured. After a pretreatment period of 21 days, ten healthy human volunteers ingested 1*10(8) cells of E. coli daily for 14 days. Thereafter a follow-up period of 28 days completed the study. The results of this study indicated that no effect of the treatment on the composition of the gut microflora could be observed. However, the immune-fluorescence measurements revealed a significant increase in circulating amounts of IgG directed against the administered E. coli cells. It is concluded that the treatment only resulted in a specific humoral immune response, while the gut microflora is not modulated.