title: Studies on the etiologic role of gram-negative bacilli in infections of the respiratory tract.
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000209:etiology*