Better ecosystem resistibility but with severer risk deriving from potential pathogens and antibiotic resistances in marine sediments adjacent to Yellow River estuary under oil contamination

Abstract

Estuaries, a vital coastal system, exhibit extensive anthropogenic impacts on their ecological integrity. However, little is known about microbial responses and associated risks in marine sediments around Yellow River estuary (YRE) at an outbreak of oil pollution. Herein, via molecular sequencing and physicochemical experiments, the characteristics of microbiota, potential pathogens and antibiotic resistance were comprehensively investigated in sediments collected from three areas with varying distances to YRE at diesel-polluted microcosms. Specifically, higher stability, stronger stochasticity-dominated assembly processes and more abundant petroleum metabolic pathways were observed in bacterial community nearest to the estuary (YE). Furthermore, an enrichment of potential pathogens and antibiotics resistance genes (ARGs), those mainly related to multidrug-resistance efflux pumps, as well as the accelerated dissemination of ARGs, all were found across all regions along the pollution time, especially those in YE. Several core pathogens (e.g., Pseudomonas) were simultaneously related with multidrug resistances and their transmissions, and a more robust relationship among them was found in YE. Culturable experiments demonstrated numerous potential pathogens were capable of efficiently degrading oil contaminants. A global investigation revealed the sediment pathogens with oil degradation potential were widely distributed in shallow- and deep-sea water bodies, with higher abundance in coastal zones, suggesting extensive pathogenic risks from these bacteria also in oil-polluted aquatic environments. Altogether, the findings unmask the sound resistibility but with serious hazard of potential pathogens and antibiotic resistance in oil-contaminated sediment ecosystem nearest to YRE, and offer novel insights and potential targets for estuarine risk assessment and control.