title: Development of ampicillin-resistance during treatment of haemophilus influenzae pneumonia.
mesh_terms: D000667:Ampicillin / Q000627:therapeutic use*; D002701:Chloramphenicol / Q000627:therapeutic use; D006192:Haemophilus Infections / Q000188:drug therapy*; D006193:Haemophilus influenzae; D006801:Humans; D008297:Male; D008875:Middle Aged; D010403:Penicillin Resistance; D011014:Pneumonia / Q000188:drug therapy*
chemical_list: D002701:Chloramphenicol; D000667:Ampicillin