[Results of a study of some methods of differentiating M. pneumoniae strains by the virulence of the degree of attenuation].

Study of five M. pneumoniae strains by the intensity of hemolysis and hemadsorption demonstrated no definite differences between them. Experiments on Cricetus auratus W. showed a higher virulence of the strains isolated from the patients with pneumonia in comparison with the strains isolated in acute respiratory diseases of the upper respiratory tracts. Attenuated straines were characterized by a weak intensity to reproduction in the lung tissue of Cricetus auratus W. and mildness of the histopathological changes which they caused.