As the DMannose passes through the kidneys, a considerable proportion of the sugar is extracted and added to the urine.  The DMannose-sweetened urine flows from the kidneys through the ureters to the bladder and on to the urethra, literally sugar-coating any free-floating E.coli it might encounter and preventing them from attaching to any cells.

It also dislodges any bacteria which already attached to the inner surface of the bladder and urinary tract, ultimately flushing them all down the toilet.