Bacteria Data

Benefits accrued by wild-type <i>E. coli </i>from antibiotic inhibition by antibiotic-resistant <i>E. coli</i> is often regarded as an example of altruism. However, how antibiotic-resistant cells respond to selection, benefit other cells, and then become positively assorted in a population remains poorly understood. Here, we show that some wild-type cells in <i>E. coli</i> population evolved into cooperative individuals via phenotypic plasticity under antibiotic pressure, and the process is rapid and reversible. Our experiments also showed a reciprocal exchange between the metabolism byproduct indole of antibiotic resistant cells and the consumption of indole by antibiotic sensitive cells. Mutually beneficial cooperation between antibiotic-resistant <i>E. coli</i> and antibiotic-sensitive <i>E. coli</i> was formed based on the metabolic byproduct indole. Such positive feedback will likely facilitate the evolution of the potentially costly reciprocal behavior, which has been previously demonstrated in both <i>E. coli</i> and <i>Salmonella enterica</i>. Identifying how variation in this mechanism drives the evolution of cooperation among bacterial cells will help us understand how bacteria evolve antibiotic resistance and facilitate the development of effective clinical treatments for antibiotic resistant microbes.