A deadly bacterial pathogen that is often found in hospitals and frequently resistant to drugs, Pseudomonas aeruginosa, is apparently able to degrade plastic that is commonly used in medical procedures. This dangerous germ can consume the polycaprolactone (PCL) that is often used in stents, sutures, dressings, drug patches, and surgical mesh, to survive. These bacteria might even live longer in hospitals and in patients because of this 'food' source. The findings, which upend assumptions about how bacteria interact with medical plastics, have been published in Cell Reports.
“It means we need to reconsider how pathogens exist in the hospital environment,” said study leader Professor Ronan McCarthy of the Brunel University of London. “Plastics, including plastic surfaces, could potentially be food for these bacteria. Pathogens with this ability could survive for longer in the hospital environment. It also means that any medical device or treatment that contains plastic could be susceptible to degradation by bacteria.”
In this study, the investigators found an enzyme called Pap1 from a type of P. aeruginosa that was first collected from a patient with a wound infection. The Pap1 enzyme was able to break down 78% of a bit of plastic within about a week, using that plastic as its only source of carbon.
The bacterium appears to become more dangerous after consuming the plastic as well. P. aeruginosa was able to form stronger biofilms after exposure to plastic. Biofilms are strong communities of bacteria that can take on new properties and become much more tenacious and hard to remove compared to a few bacterial cells. Biofilms can also resist the effects of drugs and disinfectants.
It's not only the Pap1 enzyme of P. aeuruginosa that can eat plastic, either. The researchers found indications that other microbial pathogens carry similar enzymes. It raises the possibility that medical plastics such as polyethylene terephthalate or polyurethane that are used in bone scaffolding, dental implants, catheters, or breast implants, for some examples, may also be vulnerable.
Plastic is probably helping the bacteria survive in hospitals too, and may be promoting outbreaks of infection. As such, it may be time to look for other materials that microbes cannot degrade. Researchers might have to screen pathogens for enzymes that allow bacteria to consume plastic, and integrate these findings into hospital disinfection procedures, McCarthy suggested.
However, McCarthy also noted that this is just one study, and more research should be conducted to find out more about how widespread this problem may be and how many microbes or plastics may be involved.
“Plastic is everywhere in modern medicine, and it turns out some pathogens have adapted to degrade it and we need to understand the impact this has on patient safety,” said McCarthy.
Sources: University of Brunel, Cell Reports