Antibiotics Can Actively Make Bacteria Stronger

Current understanding of the way bacteria develop resistance has been challenged. The current thought that resistance is caused by a few bacteria, which by chance had the ability to resist the antibiotic, was initially challenged when it was found that the surviving bacteria were also then more resistant to other subsequent yet different antibiotics.

A team at Harvard Medical School has found that some antibiotics actually induce mutations in bacteria. They do this by producing toxic free radicals which then result in mutations incorporated into bacterial DNA by the repair pathways. This process is greatest when drug levels are low and potentially could be blocked by inhibiting DNA repair. It is thought DNA repair inhibitors could limit the emergence of new “superbugs”

More info:
http://www.newscientist.com/article/...y-repairs.html
Molecular Cell, DOI: 10.1016/j.molcel.2010.01.003