L Forms of Bacteria as Contaminants in Tissue Culture

Abstract

THE occurrence of pleuropneumonia-like organism as contaminants in tissue culture is a common experience in many laboratories^1–5. Such infections may be inapparent or may cause progressive degeneration of the cells. The origin of this type of contamination has never been satisfactorily explained, and although the serum used in tissue culture media is often suspected we have never succeeded in isolating pleuropneumonia-like organisms from many samples of fresh human, bovine, horse and rabbit sera. Our results suggest that at least some of the pleuropneumonia-like organisms found in tissue culture are L forms of contaminating bacteria. This belief is based on the following observations.