A dangerous hospital-acquired bacteria can digest and live on plastics present in sutures, stents, wound dressings and implants in your body. Researchers from UK’s Brunel University also found that when the bacteria used plastics as its food source, it led to the formation of more biofilms — barriers that can protect the pathogen from attacks by the immune system and antibiotics. The finding means that bacteria, such as the one they studied, could degrade medical implants, lead to infections at the site of the implant and cause infections that are harder to treat. What did the researchers find? There are bacteria in the environment that have developed the capacity to break down different types of plastics. So researchers wanted to see whether bacteria that cause infections in humans could also lead to such degradation within the body. For the study, scientists looked for different pathogens with genes that could potentially produce enzymes similar to the ones that environmental bacteria use to degrade plastics. While they found several hits, they selected a Pseudomonas aeruginosa sample that came from a patient’s wound. They isolated an enzyme — which they named Pap1— that could digest a type of bio-degradable plastic frequently used in medical devices called polycaprolactone (PCL) plastic. The researchers found that the enzyme degraded 78 per cent of the plastic sample in just seven days. Importantly, the researchers found that the bacteria were not only degrading the plastic, they were also using it as their carbon source — effectively eating it. “This means we need to reconsider how pathogens exist in the hospital environment. Plastics, including plastic surfaces, could potentially be food for these bacteria. Pathogens with this ability could survive for longer in hospitals,” Dr Ronan McCarthy, author and professor of biomedical sciences at Brunel University, said in a release. Why is this concerning? This is concerning for several reasons: One, bacteria could live on in hospitals or within a patient even when there aren’t any other nutrients present. Two, they could degrade medical devices that use plastics, leading to their failure. This could lead to a rethink of materials that should be used for medical devices. Three, researchers found that the plastic-digesting bacteria could cause more severe infections. The researchers further found that the bacteria were using the broken down plastic molecules to create biofilms (a matrix made of sugars, proteins, fats and DNA) that make pathogens more resistant and difficult to treat. Four, degrading medical devices would also mean that the pathogens would be able to create pits and niches within the human body, where it could be shielded from the immune system and antibiotics, again causing difficult-to-treat infections. Are there other pathogens that could have this ability? Researchers found that other pathogens like Streptococcus pneumoniae, Klebsiella pneumoniae and Acinetobacter baumannii, too, carried genes that could potentially create plastic-digesting enzymes. More studies are needed. Importantly, the researchers found that Pap1 enzyme was structurally similar to known enzymes that can degrade even more hardy plastics such as PET bottles.
