Unravelling novel mechanisms of horizontal transfer of integrons in bacteria: implications for the dissemination of antibiotic resistance

The widespread use of antibiotics has resulted in rapid evolution of bacterial genomes facilitated by horizontal gene transfer (HGT). Class 1 integrons are dynamic genetic units responsible for the ongoing spread of resistance genes in clinical settings. Identical integrons have been found in the chromosome of unrelated bacteria suggesting the presence of mechanisms facilitating horizontal intercellular movement of integrons. In this PhD project, we present the hypothesis that HGT by natural transformatio n with released DNA may play a key role in transfer of chromosomally located integrons among clinical strains. We will describe the genetic diversity of recently discovered integrons and test the hypothesis that natural transformation is a key mechanism i nvolved in integron dynamics among clinically relevant bacteria. Understanding the mechanisms facilitating movements of integrons is important to develop effective measures to control antibiotic resistance and to unravel the molecular mechanisms behind HG T leading to rapid bacterial adaptation to pharmaceuticals.