Pseudomonas aeruginosa clinical isolates can encode plastic-degrading enzymes that allow survival on plastic and augment biofilm formation

Multiple bacteria encoding plastic-degrading enzymes have been isolated from the environment. Given the widespread use of plastic in healthcare, we hypothesized that bacterial clinical isolates may also degrade plastic. This could render plastic-containing medical devices susceptible to degradation and failure and potentially offer these pathogens a growth-sustaining substrate, enabling them to persist in the hospital-built environment. Here, we mined the genomes of prevalent pathogens and identified several species encoding enzymes with homology to known plastic-degrading enzymes. We identify a clinical isolate of Pseudomonas aeruginosa that encodes an enzyme that enables it to degrade a medically relevant plastic, polycaprolactone (PCL), by 78% in 7 days. Furthermore, this degradation enables the bacterium to utilize PCL as its sole carbon source. We also demonstrate that encoding plastic-degrading enzymes can enhance biofilm formation and pathogenicity. Given the central role of plastic in healthcare, screening nosocomial bacteria for plastic-degrading capacity should be an important future consideration.