Abstract
The interaction between nanoplastics and bacteria remains still largely unclear. In this study, we determined the effect of nanopolystyrene particle (NP) on a bacterial pathogen of Acinetobacter johnsonii AC15. Scanning electron microscopy (SEM) analysis indicated the aggregation of NPs from 10 μg/L to 100 μg/L on surface of A. johnsonii AC15, suggesting that A. johnsonii AC15 acted as the vector for NPs. Exposure to 100−1000 μg/L NPs increased the growth and colony-forming unit (CFU) of A. johnsonii AC15. In addition, exposure to 100−1000 μg/L NPs enhanced the amount of formed biofilm of A. johnsonii AC15. Alterations in expressions of 3 survival-related (zigA, basD, and zur), 5 biofilm formation-related (ompA, bap, adeG, csuC, and csuD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were observed after exposure to 1000 μg/L NPs. Moreover, both CFU and survival rate of A. johnsonii AC15 in normal human serum (NHS) were significantly increased by 1−1000 μg/L NPs, suggesting the enhancement in serum resistance of Acinetobacter pathogen by NPs. In the NHS, expressions of 3 survival-related (zigA, basD, and zur), 9 biofilm formation-related (ompA, bap, adeF, adeG, csuA/B, csuC, csuD, csuE, and hlyD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were affected by 1000 μg/L NPs. Expressions of 1 survival-related (zigA), 5 biofilm formation-related (bap, adeG, csuC, csuD, and csuE), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were also altered by 10 μg/L NPs after the addition of NHS. Therefore, exposure to NPs in the range of μg/L has the potential to enhance bacterial virulence by increasing their growth, biofilm formation, and serum resistance.