Bacteria use viral genetic material for self-immunity

Bacteria, like humans, can be attacked by viruses. These viruses are known as bacteriophages, or phages. Researchers at Johns Hopkins Medicine are exploring how bacteria survive these infections to gain insights into human immunity and develop new medical treatments. The scientists discovered that Streptococcus pyogenes bacteria can protect themselves by taking genetic material from dormant phages. This process acts like a vaccination, helping the bacteria prepare an immune response against potential future attacks. When the phage is dormant, the bacteria capture parts of its DNA, which they pass on to their offspring, creating a memory of the invader. This research could explain how certain bacteria, such as those responsible for strep throat and other serious infections, become harmful to humans. The researchers focus on temperate phages, which can either kill bacteria or go dormant, allowing bacteria to form a memory of the virus without immediate danger. To conduct their study, the team infected bacterial populations with both natural dormant phages and engineered non-dormant phages. They found that the bacteria's CRISPR system was more efficient in capturing DNA from dormant phages. This system acts as a record of past infections, allowing bacteria to defend against future threats effectively. The scientists are hopeful that these findings can lead to improvements in phage therapies. These therapies could help treat bacterial infections that do not respond to antibiotics. The next steps in their research will explore how CRISPR systems can defend against viruses that remain active instead of going dormant.