Clostridium difficile in the normal adult faecal flora.

One hundred and seventy-seven out of 324 routine non-diarrhoeal faecal specimens investigated for the presence of Clostridium difficile were culture-positive. Twelve of the faecal specimens obtained from thirty-six normal healthy volunteers yielded Cl. difficile prior to oral administration of clindamycin. Thereafter all the volunteers excreted the organism from the second day to the fifth day during clindamycin administration. Three months after stoppage of oral clindamycin sixteen of the thirty-six volunteers still excreted Cl. difficile. Peak or trough serum levels of clindamycin had no relationship with the density of growth. None of the volunteers developed any Cl. difficile associated diseases.