Evidence for biliary excretion of vancomycin into stool during intravenous therapy: potential implications for rectal colonization with vancomycin-resistant enterococci.

Sixty-three stool samples and five bile samples were prospectively collected from 33 patients receiving intravenous vancomycin therapy and were quantitatively analyzed for vancomycin by a competitive immunoassay. Vancomycin was excreted via bile into the stools of almost all patients at concentrations of 3.3 to 94.8 microg/ml after >/=5 days of a therapy of 1 g every 12 h.