Uncontacted Amerindians and Antibiotic-Resistance Genes

Richard T. Ellison III, MD reviewing Clemente JC et al. Sci Adv 2015 Apr 17.

Remote Amazonian villagers with no known previous Western contact have a highly diverse microbiome that includes bacteria carrying antibiotic-resistance genes.

Knowledge of the human microbiome is certain to have immense implications for our understanding of human physiology. One concern is the likelihood of marked alterations in the microbiome over the last century due to changes in lifestyle and the widespread use of antimicrobial agents. To gain insight into the microbiome before these transitions, researchers analyzed samples collected from Yanomami villagers during a medical mission to a remote region of the Amazon jungle in Venezuela. Inhabitants of this area were not known to have had previous contact with the modern world.

Samples from the oral cavity, skin, and feces collected from 34 villagers were subjected to 16S ribosomal RNA and metagenomic analyses. The microbiome was found to have the greatest diversity ever reported in any human population. Phenotypic resistance testing of 131 Escherichia coli strains isolated from the fecal samples showed susceptibility to 23 antibiotics. However, functional libraries created from the genomic DNA of such strains revealed the presence of 28 antibiotic-resistance genes, including ones that confer resistance to penicillin, piperacillin, piperacillin-tazobactam, ceftazidime, aztreonam, chloramphenicol, tetracycline, and tigecycline.

CITATION(S):

Clemente JC et al. The microbiome of uncontacted Amerindians. Sci Adv 2015 Apr 17; 1:e1500183.