The homogeneity of the faecal coliform flora of normal school-girls, characterized by serological and biochemical properties

The homogeneity of fecal coliform flora in 52 schoolgirls was studied by serotyping and biotyping 10 randomly selected colonies in one fecal culture from each child. Ninety-eight clones were identified and of these 52 were dominant and 46 were minor strains. The probability of including at least one isolate of the dominant clone in a small random sample of colonies was calculated to be 86% for one colony, 94% for 2, 97% for 3, 99% for 4, and 99.3% for 5 randomly selected colonies.