The microbiome of uncontacted Amerindians.
Level 4 - case-series / case-control
Cross-sectional characterization of an isolated human cohort (design analogy, not clinical CEBM)
PubMed 26229982 · doi:10.1126/sciadv.1500183
What was done
Researchers characterized the fecal, oral, and skin bacterial microbiome and resistome from members of an isolated Yanomami Amerindian village with no documented prior contact with Western populations and no known exposure to antibiotics.
What was found
The Yanomami villagers harbored the highest bacterial and functional genetic diversity reported in any human population to date. Despite over 11,000 years of presumed ancestral isolation and zero commercial antibiotic exposure, their bacteria contained functional antibiotic resistance genes, including resistance elements active against synthetic antibiotics syntenic with genetic mobilization elements. The abstract reported no specific sample sizes or quantitative metrics.
Why it matters
This study indicates that modern westernization substantially reduces human microbiome diversity and reveals that functional antibiotic resistance genes naturally reside within the human microbiome even in the complete absence of pharmacological antibiotic pressure.
Limits
The abstract does not state the sample size, participant age or sex distribution, or specific quantitative values for diversity and gene expression. Findings are derived from a single cross-sectional cohort at one village, limiting comparisons across diverse non-Western ecological settings.
Cited by
- supports Indigenous hunter-gatherer populations can have a gut microbiome diversity that is tenfold higher than that of individuals living in modern industrialized societies.