Persistence and isolation of L cycle forms of Erysipelothrix rhusiopathiae in experimental infection.

In experimental infection of rats induced with teh S-form of Erysipelothrix rhusiopathiae the pathogen was found to persist for a long time (up to fifteen months according to the author's personal observations). Under the effect of the specific and unspecific defense of the animal's organism the causative agent suffered a number of morphologic changes. In the course of the first days of infection the R-form was isolated, and thirty days later up to the fifteenth month forms of the L cycle were recovered from the parenchymal organs, blood, and joints. An electron microscopic study was carried out on the structure of the isolated L-forms. The long-term persistence of the agent in its different morphologic forms may well account for the chronic course of the infection in rats.