全球化趋势对与我们相伴的菌群影响会有多大？最近对生活在委内瑞拉原始部落土著（Yanomami人）身上菌群的研究能给我们一些启示。这些土著从来不曾和外界有过任何接触。

2009年，委内瑞拉的科学家第一次与这一部落接触，并采集了年龄从4岁到50岁的34位村民口腔，皮肤和粪便细菌样品。来自美国的科学家对样品中细菌的多样性进行了分析。通过与美国人群，还有其它两个与西方文明仅有有限接触的人群（来自委内瑞拉的Guahibo，和非洲Malawi农村社区的人），惊奇的发现与世隔绝的Yanomami人身上的菌群存在高度的多样性：anomami人的细菌多样性是美国人的两倍，比后两类人群的多样性高出30%-40%说明，即便是低限度的接触现代生活方式，也能导致菌群多样性的大幅度下降；而且有些anomami人皮肤上细菌在西方生活方式的人身上已经消失，只在土壤样品中才可以检测到它们。

另外一点就是，虽然anomami人可能从来没有和我们一样暴露过抗生素，他们的口腔和肠道微生物对抗生素反应很敏感，但是他们的菌群中确实存在抵抗现代合成的包括三代和四代的头孢菌素的抗生素抗性基因，这提示抗生素抗性是菌群的一种自然特性，只是通过抗生素滥用，这类抗性更倾向于活化形成强烈的对抗抗生素杀伤的能力。

原文：http://advances.sciencemag.org/content/1/3/e1500183

Abstract

Most studies of the human microbiome have focused on westernized people with life-style practices that decrease microbial survival and transmission, or on traditional societies that are currently in transition to westernization. We characterize the fecal, oral, and skin bacterial microbiome and resistome of members of an isolated Yanomami Amerindian village with no documented previous contact with Western people. These Yanomami harbor a microbiome with the highest diversity of bacteria and genetic functions ever reported in a human group. Despite their isolation, presumably for >11,000 years since their ancestors arrived in South America, and no known exposure to antibiotics, they harbor bacteria that carry functional antibiotic resistance (AR) genes, including those that confer resistance to synthetic antibiotics and are syntenic with mobilization elements. These results suggest that westernization significantly affects human microbiome diversity and that functional AR genes appear to be a feature of the human microbiome even in the absence of exposure to commercial antibiotics. AR genes are likely poised for mobilization and enrichment upon exposure to pharmacological levels of antibiotics. Our findings emphasize the need for extensive characterization of the function of the microbiome and resistome in remote nonwesternized populations before globalization of modern practices affects potentially beneficial bacteria harbored in the human body.

群晓生物

http://blog.sina.com.cn/s/blog_7038ff370102vfyj.html