Electron microscopic studies on altered forms of Erysipelothrix rhusiopathiae obtained under the effect of novobiocin.

Altered and L-forms of Erysipelothrix rhusiopathiae were obtained through in vitro and in vivo treatments with novobiocin. Electron microscopic studies were carried out on the changes taking place in the morphology and ultrastructure of strains showing a varying degree of resistance. When lower concentrations of the antibiotic were employed (15, 25, 200, 400 mcg) strongly elongated and threadlike forms were established manifesting characteristic changes in the cell wall and the inner structure. The use of high concentrations of novobiocin (1000 and 2000 mcg) incited the production of L-forms the morphology and ultrastructure of which are dealt with in detail.