As the rate of hospital acquired infections (HAIs) grows, ballooning to 1.7 million every year and resulting in 99,000 deaths, a solution is urgent. But the solution, some scientists say, won’t come from new antibiotics but from “living medicine.”
The term biofilm is not common for many of us, but an example we’re all familiar with is the plaque that forms on teeth and causes tooth decay.
It consists of a multi-layered colony of bacteria that clump together and are held in place by a matrix of sugary molecular strands called extracellular polymeric substances, meaning that they form outside the walls of cells.
This enables them to resist attack from the body’s immune system and makes them highly resistant to penetration by antibiotics.
In hospital settings these antibiotic resistant bacteria are a real problem, particularly in patients with medical implants. The broad-spectrum drug treatments currently on offer are highly toxic to normal tissues and produce nasty side effects.
However, researchers at The Barcelona Institute of Science and Technology say they’ve come up with a better idea.
Genetically Manipulated Bacteria
The Spanish team tested the idea of introducing living, genetically manipulated, enzyme-producing bacteria to dissolve dangerous biofilm.They chose a common species of bacteria called Mycoplasma pneumoniae, which can cause mild infections of the respiratory system. They picked this species because it lacks a cell wall. This makes it easier to release the enzymes, helps it evade the human immune system, confers a low risk of mutating, and won’t allow the bacteria to transfer any of its modified genes to other microbes in the vicinity.
The scientists’ first task was to modify the bacteria so it wouldn’t cause illness. Next, they tweaked it some more to produce two enzymes to dissolve the biofilm. Once this was completed the bacteria could now attack the cell walls of the biofilm bacteria that were embedded within and kill them. A further modification allowed the treatment bacteria to secrete antimicrobial enzymes more efficiently.
Healed 82 Percent of Mice
Once completed, the Spanish team tested the experimental treatment on infected catheters using three different methods. Their testing proved successful in each case.One of the methods involved injecting the living medicine under the skin of mice. The researchers reported that this treatment cured the infection in 82 percent of them.
Professor Luis Serrano, a member of the research team, said, "Bacteria are ideal vehicles for 'living medicine' because they can carry any given therapeutic protein to treat the source of a disease.
“One of the great benefits of the technology is that once they reach their destination, bacterial vectors offer continuous and localized production of the therapeutic molecule. Like any vehicle, our bacteria can be modified with different payloads that target different diseases, with potentially more applications in the future."
The Spanish team expects to start human clinical trials in 2023—I’ll keep you posted on their findings.
