R-047. Amerindian Helicobacter pylori strains Go Extinct, as European Strains Expand their Host Range

M. G. Dominguez-Bello1, M. E. Pérez1, M. C. Bortolini2, F. M. Salzano2, L. R. Pericchi1, O. Zambrano-Guzmán3, B. Linz4;
1Univ. of Puerto Rico, San Juan, PR, 2Univ. Federal Rio Grande do Sul, Porto Alegre, BRAZIL, 3Univ. Pedagogica Experimental Libertador, Puerto Ayacucho, VENEZUELA, 4Max-Planck Inst. für Infektionsbiologie, Berlin, GERMANY.

As in other microbial environments, diversity of resources in the human body is predicted to provide niche diversification and species diversity. The evolutionary dynamics and ecological changes in microbes across human diversity have not been assessed. Since niche diversity widens the sets of microbiome resources, we hypothesized that high human diversity increased diversity of associated microbes. We studied population diversity in the H. pylori-human binomial natural experiment. H. pylori, associated with human gastric diseases, diverged along with humans, and strains from African, European, Asian and Amerindian ancestry can be recognized. Bacterial strains with Amerindian ancestry were found to be the least diverse, and those from European affiliation were the most diverse, had a mosaic structure reflecting recombination and had an expanded host range that included Spanish, Mestizos and Native Americans. In contrast, Amerindian strains seem to lack the needed diversity to survive the host diversity in non Amerindian hosts.