In a new study, researchers found that a probiotic drink could become a promising new weapon in the battle against antibiotic-resistant bacteria.
It works by targeting small DNA molecules, called plasmids, inside bacterial cells. These molecules frequently carry genes that give resistance to antibiotics, which the bacteria are able to use.
The plasmids replicate independently, spreading between bacteria and carrying resistance genes with them.
By preventing the target plasmids from replicating, the team was able to displace the resistance genes available to the bacteria, effectively ‘re-sensitising’ them to antibiotics.
The research was conducted by a team of scientists at the University of Birmingham.
Antibiotic resistance is one of the biggest medical challenges. Doctors need to be tackling this on a number of different fronts including by reducing the use of antibiotics and searching for new, more effective drugs.
The drink will contain bacteria (in a similar way to drinks like Yakult) carrying a new type of plasmid, which the researchers call pCURE plasmids.
These work in two ways: they prevent the resistance plasmids from replicating and they also block a so-called ‘addiction system’ which the plasmids use to kill any bacteria that lose them.
In this system, the resistance plasmid carries a stable toxin and an unstable antidote into the host cell. If the plasmid is lost from the cell, the antidote breaks down, leaving the harmful toxin to attack its host.
pCURE plasmids also carry the antidote, ensuring that cells that lose the resistance plasmid survive and take over the gut.
The team discovered that by doubling the number of copies of the pCURE plasmid in each bacterium it became very effective at displacing different types of resistance plasmids and would spread through laboratory cultures unaided, to clear out resistance.
The team then collaborated with colleagues at the University of Sydney, Australia, to test the pCURE plasmids in mice. They found the pCURE plasmids worked effectively.
The next step is to see if plasmids can spread fast enough in human volunteers to get rid of resistance plasmids.
One author of the study is Professor Christopher Thomas.
The study is published in the journal PLOS ONE.
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