Effect of crude oil, dispersant and oil-dispersant mixtures on human intestinal microbiota

The Deepwater Horizon oil spill raised concern that the dispersant and dispersed oil as well as crude oil itself could contaminate shellfish and seafood habitats. Little is known about the effects of crude oil and dispersant incurred seafood residues if ingested by the consumer on the human intestinal microbiota. The aim of this research was to evaluate the potential impact of Deepwater Horizon crude oil and Corexit 9500 dispersant on human intestinal microbiota. In vitro cultures containing human fecal microbiota from healthy adults were treated with oil, dispersant and oil-dispersant mixtures and perturbations to the microbial community were monitored using denaturing gradient gel electrophoresis (DGGE) and pyrosequencing analysis. The molecular data indicated that the intestinal microbiota was impacted by oil alone and dispersed oil exposures, and the influences due to oil and dispersed oil were different to each other. The phylum of Bacteroidetes was decreased with increasing proportion of crude oil treated and oil-dispersant combination mixture samples in all individuals. While the Proteobacteria was increased in dispersed oil treated samples, there was variability in the changes of Proteobacteria in crude oil treated samples. At the species level, Bacteroides uniformis and Escherichia coli were affected more by dispersed oil than by oil alone exposure. The significant effects of dispersed oil on the human intestinal microbiota were observed by Principal Coordinate Analysis (PCoA). In conclusion, our study indicated that the intestinal microbiota was affected differently by oil and dispersed oil combinations, and intestinal microbiota was more significantly impacted by dispersed oil than oil and dispersant alone.