Scientists have recently begun to discover ways in which they can adapt parts of bacteria DNA in order to destroy the pathogens inside. Some strands of DNA can easily move between bacteria strains. By doing this they introduce genes that produce new toxins which in turn make the strain more dangerous. Scientists are now able to replace the toxic genes with genes that have shown the ability to battle staph bacteria. The tests have so far been highly effective in mice.
If they have a similar effect in humans, these genes could provide a solid alternative to the antibiotics used today. This is especially true for some of the deadlier strains of the Staphylococcus aureus bacteria.
These same strands of DNA, which are also known as pathogenicity islands, have already displayed the ability to “sabotage” genes from the inside. Combining stretches of this DNA creates ideal conditions for implementing new genes into bacteria. These small packages of DNA are then used as Trojan horses, as they replace the genes that produce toxins with CRISPR sequences which then alter the DNA of the bacteria.
One of the CRISPR sequences was able to cut the staph DNA effectively killing the bacteria. Another version was able to attach itself to the gene that controls the harmfulness of the staph bacteria and make it less effective.
These DNA packages or drones as the scientists like to call them have gone through extensive testing in mice. Researchers injected both versions of the CRISPR sequences underneath the mice skin, avoiding the creation of abscesses. The mice which received a deadly dose of staph bacteria were able to survive when injected with the first version of the CRISPR sequence.
In a way, the use of these packages is similar to phage therapy. Phage therapy is an alternative to the use of antibiotics. During this treatment patients consume cocktails which contain different bacteriophages. Bacteriophages are viruses that specifically target bacteria. This practice is still not available in the United States, as it is not FDA approved. It has seen use, and more importantly, success, in Eastern European countries.
The CRISPR treatment shows more promise though. A phage needs to reproduce in a cell to be effective in killing it. The “drones” only eliminate a gene which in turn kills the bacteria.
But this treatment still needs to be perfected. Some bacterial strains have shown resistance towards both CRISPR versions. We are a long way from clinical testing and the next step is applying this to other infections that develop as a result of staph.