Antibiotics may cause bacteria to mutate, reproduce faster

"Our research suggests there could be added benefits for E coli bacteria when they evolve resistance to clinical levels of antibiotics," said Robert Beardmore, Professor at University of Exeter.
This was only seen in bacteria exposed to antibiotics - and when researchers took the drug away, the evolutionary changes were not undone and the new-found abilities remained.

Antibiotics may cause bacteria to mutate into “uber-bugs” which reproduce much faster, say scientists who found that a bug which causes severe stomach pain, diarrhoea and kidney failure in humans had increased resistance after each round of drug treatment.

Researchers at University of Exeter in the UK exposed E coli bacteria to eight rounds of antibiotic treatment.

They found that mutated E coli reproduced faster than before encountering the drugs and formed populations that were three times larger because of the mutations. Full Story