title: Letter: Prevention of gram-negative pneumonia.
mesh_terms: D001424:Bacterial Infections / Q000517:prevention & control*; D002986:Clinical Trials as Topic; D006801:Humans; D011014:Pneumonia / Q000517:prevention & control*; D011113:Polymyxins / Q000627:therapeutic use*
chemical_list: D011113:Polymyxins