Resistance can spread even without the use of antibiotics

Bacteria are becoming increasingly resistant to common antibiotics. Often, resistance is mediated by resistance genes, which can simply jump from one bacterial population to the next. It’s a common assumption that the resistance genes spread primarily when antibiotics are used, a rationale backed up by Darwin’s theory: only in cases where antibiotics are actually being used does a resistant bacterium have an advantage over other bacteria. In an antibiotic-free environment, resistant bacteria have no advantage. This explains why health experts are concerned about the excessive use of antibiotics and call for more restrictions on their use.

However, a team of researchers led by scientists from ETH Zurich and the University of Basel have now discovered an additional, previously unknown mechanism that spreads resistance in intestinal bacteria that is independent of the use of antibiotics.