I just saw this on Science Blog : a common food preservative may be very powerful against the kind of bacterial infection which is so destructive to Cystic Fibrosis Sufferers. Mutations which cause CF in humans result in abnormally thick and acidic mucus. Bacteria such as Pseudomonas aeruginosa which can get in there are effectively shielded from the immune system by the mucus and their own deposits, which are referred to as alginate.
Now, in recent study of American CF patients, 84% of the Pseudomonas aeruginosa isolates themselves carried a mutation in the gene MucA. This mutation allows the bacteria to make more alginate, which in turn gives the mutant bacteria an improved shield against the immune system relative to the wild-type bugs. Here's where the story gets really cool- this same mutation makes the mutant bugs (which are frustratingly resistant to antibiotic or immune therapy) very sensitive to acidified sodium nitrite, a compound used as a preservative for hot dogs or bacon. So in principal this nitrite could be made into an aerosol and clear up the mutant bacteria; and other therapies could help get the rest.
The original reference is here.
For a description of recent work on saline washes as a way of getting the sticky mucus of CF sufferers out, see Aetiology.