World's first 'living medicine' that could treat drug-resistant lung infections

To treat lung infections, researchers have developed the first "living medicine". A prevalent cause of infections in hospitals, Pseudomonas aeruginosa is a form of bacteria that is naturally resistant to many different types of antibiotics.

A modified form of the bacteria called Mycoplasma pneumoniae that has been repurposed to fight P. aeruginosa instead of causing disease is used in the treatment. Low doses of antibiotics that would not ordinarily be effective alone are combined with the transformed bacterium.

Researchers examined the treatment's effectiveness in mice and discovered that it greatly decreased lung infections. Compared to the mouse's survival rate without therapy, the "living medication" doubled it. No toxicity was visible in the lungs following the administration of a single, high dose of the medication. The transformed bacteria were eradicated by the innate immune system four days after the course of treatment was complete, reported Medical News.

The research was published in the journal Nature Biotechnology.

Since P. aeruginosa bacteria reside in communities called biofilms, treating infections caused by them can be challenging. Biofilms are impermeable formations that can grow on a variety of bodily surfaces and resist antibiotic treatment.

Endotracheal tubes used by severely ill patients who need mechanical ventilators to breathe can develop P. aeruginosa biofilms on their surface. This results in ventilator-associated pneumonia (VAP), which affects one in four patients (9–27% of those who need intubation). VAP can cause an ICU stay to extend by up to 13 days and can be fatal for up to one in eight patients (9–13%).

By giving M. pneumoniae the ability to manufacture numerous compounds, including pyocins, which are toxins naturally produced by bacteria to kill or limit the growth of Pseudomonas bacterial strains, the study's authors modified M. pneumoniae to disintegrate biofilms. 

They took P. aeruginosa biofilms from the endotracheal tubes of intensive care unit patients to test the treatment's effectiveness. They discovered that the therapy broke through the barrier and effectively removed the biofilms.

Before beginning the clinical trial phase, the researchers will conduct more studies with the goal of using "living medicine" to treat VAP. A nebuliser, which is a machine that transforms liquid medication into a mist that is then inhaled through a mouthpiece or a mask, will likely be used to provide the treatment.