Bacterial cooperation leads to heteroresistance

By challenging E. coli with sublethal norfloxacin for 10 days, Henry Lee and James Collins suggests the bacterial altruism leads to the population-wide resistance. By detailedly analyzing experiment data, we suggest that bacterial cooperation leads to population-wide resistance under norfloxacin pressure and simultaneously propose the bacteria shield is the possible feedback mechanism of less resistant bacteria. The bacteria shield is that the less resistant bacteria sacrifice the large number of themselves to consume norfloxacin and then to relieve the norfloxacin burden from highly resistant bacteria. Moreover, by employing Game Theory, the interaction between highly resistant bacteria and less resistant bacteria under norfloxacin can be considered as Iterated Prisoner’s Dilemma and the best strategy is to cooperate with each other, which agrees with bacterial cooperation achieved by analyzing experiment data. Thus, due to highly resistant bacteria and less resistant bacteria extracted from the same bacteria population, bacterial cooperation leads to heteroresistance. Additionally, the genetic relatedness of highly resistant bacteria and less resistant bacteria are very close, but the bacteria cooperate with each other, which provides a contradiction against Kin Selection Theory.