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CALCULUS IS A LONG-TERM RESERVOIR OF DISEASE
The rst detailed analysis of ancient oral microbiome ecology and function has revealed that despite signicant changes in diet and
lifestyle over the last 1,000years, the oral cavity has been a long-term host for opportunistic pathogens that initiate oral and respiratory diseases, as well as bacteria associated with the development of heart disease and other systemic diseases.
The study published in Nature Genetics analysed fouradult human skeletons from the medieval monastic site of Dalheim, Germany (c.950-1200AD), which presented evidence of mild to severe periodontal diseases, as well as the dental calculus of ninetwenty-rstcentury individuals with known dental histories. Previously, ve common oral bacteria have been identied in historic dental calculus, but by applying shotgun DNA sequencing the researchers were able to distinguish 40putative opportunistic pathogens, nding the calculus strongly dominated by bacterial DNA.
DNA sequences also revealed antibiotic resistance genes, suggesting that even before therapeutic antibiotics were used by humans, the oral cavity functioned as a source of low-level antibiotic resistance. Forty-threehuman proteins were identiedin the calculus, 25of which are involved in the innate immune system, driving inammation and host defence processes. The wealth of inammatory
proteins supports the evidence of attachment loss and active periodontal disease.
As well as the researchers providing direct insight into common diseases of the human evolutionary past, their studyalso used plant and...