[Isolation of L-form of Yersinia pestis from wild rodents in an epizootic focus].

Four Y. pestis cultures with unbalanced growth and 15 Y. pestis cultures in unstable L-forms were isolated from wild rodents Rhombomys opimus in the vicinity of lake Balkhash. Morphologically they were mainly represented by granular, spheroplast-like and filiform elements. When stained with luminescent serum, they acquired specific fluorescence; in indirect hemagglutination they yielded positive result. Electron microscopy revealed the presence of morphological elements characteristic of the process of L-transformation. After subculturing reversion to rod-like forms was observed in 13 Y. pestis strains.