THE PATHOLOGICAL EFFECT OF PEPTIDOGLYCAN ON RATS’ LUNGS PART ONE: PATHOGENIC BACTERIA STREPTOCOCCUS PNEUMONIAE

Twenty isolates of Streptococcus were obtained from fifty sputum specimens collected from patients presented with respiratory tract infections. Two of these isolates were identified as S. pneumoniae by conventional biochemical tests. For extraction of peptidoglycan from S. pneumoniae, mechanical disintegration by glass beads and vortex plus enzymatic digestion by DNase, RNase and pronase were applied. The partial purified peptidoglycan showed four protein bands compared with crude peptidoglycan which showed six bands when performed in polyacrylamide gel electrophoresis under undenaturing conditions. The rats injected with germ suspension or the peptidoglycan showed similar histopathological changes included disruption of alveoli walls, haemorrhage, infiltration of inflammatory cells, sloughing of the epithelial cells lining the bronchioles, and edema. The effects of histopathological changes of the peptidoglycan of S. pneumoniae were more severe than those of cell suspension