Reaction of mouse lung tissue on the experimental airborne Klebsiella pneumoniae infection.

There are described the histological changes in the lung tissue of mice after airborne infection with the strains of Klebsiella pneumoniae CNCTC Klp 80/66 and CNCTC 82/67 whose clearance is significantly different. Using the strain Klp 82/67, which is fairly prompt eliminated from lungs, no morphological changes in the mucous membrane of bronchi were found. Using the strain Klp 80/66, which is characterised by a multiplication of organisms in the lungs already in the initial phase of infection without any remarkable adaptative phase, the accumulation of neutrophils in the walls and on the surface of bronchi was observed. The accumulation retarded during 48 hours when mostly the mononuclear cells were present. Uptake of 3H-thymidine in the lung tissue in vivo demonstrated that the proliferation response of bronchial lymphoid tissue is a relatively early reaction. Histological examination of spontaneously died animals revealed the changes characteristic for the purulent bronchopneumonia. The pathogenic activity of various Klebsiella pneumoniae strains is obviously conditioned by at least two factors, i. e. by surface structures determining the rate of bacterial elimination from the lungs and by the lipoprotein components of the cell walls inducing the leucocytes mobilization into bronchial tissue.