Abstracts (first author)
Deadly antibiotics and evolutionary rescue via horizontal gene transfer
Evolution has caused one of the most concrete problems in the modern world by selecting for drug resistant bacteria. When bacteria are exposed to lethal levels of antibiotics, it has been assumed that there needs to be a pre-existing mutation for resistance within the population in order for the bacterial strain to survive the drug treatment. However and given that majority of resistance genes are carried by mobile genetic elements such as conjugative plasmids that can move between bacterial cells, it is possible that the resistance gene pre-exist in another bacterium which then rescues susceptible bacteria via horizontal gene transfer. We investigated whether bacteria may survive lethal antibiotic selection by acquiring resistance genes horizontally, and, if so, could this process be somehow prevented. Indeed and contradictory to previous paradigm, we demonstrate that the resistance does not need to pre-exist within the population as some bacteriosidic antibiotics cannot kill susceptible bacteria when the surrounding bacterial community carries mobile elements with resistance genes. Moreover, we show that viruses specifically infecting bacteria with mobile elements can both prevent the spread of resistances to other bacteria and to lead to the loss of resistance conferring elements from the population. Altogether these results suggest that the composition of bacterial community along with their viruses can play a defining role in the evolution antibiotic resistances.