Polystyrene nanoplastics foster Escherichia coli O157:H7 growth and antibiotic resistance with a stimulating effect on metabolism

The ever-increasing environmental risks posed by nanoplastics (NPs) have been drawing more concerns to their biological effects, but with limited information on pathogenic bacteria. This work reported the alterations in bacteriological properties of Escherichia coli O157:H7 (E. coli O157:H7) under exposure to polystyrene (PS) NPs of different sizes. Results found that E. coli O157:H7 growth was promoted by the addition of PS-NPs. At environmentally relevant exposure levels, E. coli O157:H7 underwent metabolic adaptation after different PS-NP treatments, showing differentiated responsive volatile metabolic features. Moreover, enzymatic activity analysis suggested that E. coli O157:H7 could address PS-NP-induced oxidative stress mainly via supporting glutathione (GSH) synthesis. Furthermore, it could fuel the TCA cycle through highly expressing regulatory enzymes as well with a greater response to small PS-NPs. Also, there was an observed increase in the expression of the AcrAB-TolC efflux pump after the treatment of PS below 100 nm and with a possible consequence of heightening E. coli O157:H7 resistance. Together, our findings provided the first look into the potential implications mediated by PS nanoparticles on E. coli O157:H7 growth and development and in turn emphasized a potential increased contamination of E. coli O157:H7 as a waterborne pathogen in PS-NP polluted water.