430: Phage Stimulated by Antibiotic Exposure
A recent paper in Applied and Environmental Microbiology demonstrated that exposure to the antibiotic norfloxacin to E. coli O157:H7 resulted in increased transcription of gene products associated with Stx phage. I'll take the time to explain this in English. O157:H7 is a strain of E. coli that can caused lethal food poisoning, and is also found in cattle (where it doesn't cause disease). Some of the really nasty compounds that cause disease ('shiga toxins') are encoded by genes found in bacterial viruses, or phage. Essentially, when the bacterium is exposed to antibiotics, the cell produces more toxins.
That means that more virulent E coli result from inadequate antibiotic treatment.