Researchers at Washington University have discovered that intestinal bacteria can cause people (AKA bacterial growth medium) to produce an antibiotic that is specific to invading bacteria. Angiogenins, thought to promote blood vessel growth, apparently are an effective and specific antibiotic (and not only bacteria, but yeast too). Our bodies don’t think all bacteria are bad – not only do we need them for certain vital tasks, we take care not kill those off when we try to kill off the ones that attack us.
You might recall the big hoopla around angiogenins awhile back because researchers discovered they could cure cancer in mice with anti-angiogenic compound – they could starve a tumor by taking away its blood supply. Sadly, it hasn’t seemed to work in humans. Sadly, I couldn’t find a decent link, so you’ll just have to rely on my memory.