Effects of long-term metal exposure on the structure and co-occurrence patterns of the oral microbiota of residents surrounding a mining area

This study aimed to investigate the effects of long-term exposure to heavy metals on the microbiome of the buccal mucosa. Subjects were divided into two groups: the exposure group and the control group. The most abundant bacteria identified at the phylum level were Firmicutes, Actinobacteriota, Proteobacteria. Due to long-term exposure to heavy metals, the relative abundance of Rhodococcus, Delftia, Fusobacterium, and Peptostreptococcus increased, while the abundance of Streptococcus, Gemella, Prevotella, Granulicatella, and Porphyromonas reduced. The concentration of heavy metals in the blood (Pb, Cd, Hg, and Mo) are associated with the growth of Rhodococcus, Delftia, Porphyromonas, and Gemella. In addition, the relative abundance of some pathogenic bacteria, such as Streptococcus anginosus, S. gordonii, and S. mutans, were found to be enriched in the exposure group. Altogether, this work should improve our understanding of environmental pollution and the structure of oral microbial communities.