A recent study from the Fineran Lab has shown that bacterial immune systems can increase the transduction of bacterial genetic material, such as the genes associated with antibiotic resistance. The findings have been published in the latest issue of mBio, a premier journal of the American Society for Microbiology.
Transduction, the phage-mediated transfer of bacterial DNA between cells, has a significant impact on horizontal gene transfer. In some bacteria, the spread of bacterial genetic material between cells is prevented by a type of immune system called CRISPR-Cas, which is conceptually similar to the human immune system.
Prior research has demonstrated that this system can also block invasion by phages (viruses that infect bacteria). However, authors Bridget Watson (PhD student), Dr Raymond Staals (former Postdoctoral Fellow) and Associate Professor Peter Fineran (PI) have discovered unexpectedly that CRISPR-Cas can actually enhance the spread of genetic material when it is transferred by phages.
The generation of genetic diversity through acquisition of DNA is a powerful contributor to microbial evolution, and so the results of this study may provide insight into how genes that cause resistance to antimicrobial drugs can still spread in the presence of CRISPR-Cas immune systems.