Environmental Microbiology Laboratory, Department of Biology, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931.
Microbiol Spectr. 2017 Jan;5(1). doi: 10.1128/microbiolspec.EMF-0009-2016.
As the "human microbiome era" continues, there is an increasing awareness of our resident microbiota and its indispensable role in our fitness as holobionts. However, the host-microbe relationship is not so clearly defined for some human symbionts. Here we discuss examples of "accidental pathogens," meaning previously nonpathogenic and/or environmental microbes thought to have inadvertently experienced an evolutionary shift toward pathogenicity. For instance, symbionts such as Helicobacter pylori and JC polyomavirus have been shown to have accompanied humans since prehistoric times and are still abundant in extant populations as part of the microbiome. And yet, the relationship between a subgroup of these microbes and their human hosts seems to have changed with time, and they have recently gained notoriety as gastrointestinal and neuropathogens, respectively. On the other hand, environmental microbes such as Legionella spp. have recently experienced a shift in host range and are now a major problem in industrialized countries as a result of artificial ecosystems. Other variables involved in this accidental phenomenon could be the apparent change or reduction in the diversity of human-associated microbiota because of modern medicine and lifestyles. All of this could result in an increased prevalence of accidental pathogens in the form of emerging pathogens.
随着“人类微生物组时代”的继续，人们越来越意识到我们体内的常驻微生物及其作为整体生物的不可或缺的作用。然而，对于一些人类共生微生物来说，宿主-微生物的关系并不是那么明确。在这里，我们讨论了一些“偶然病原体”的例子，也就是说，以前被认为是非致病性的和/或环境微生物，它们被认为是无意中经历了向致病性的进化转变。例如，像幽门螺杆菌和 JC 多瘤病毒这样的共生体，从史前时代就一直伴随着人类，并且作为微生物组的一部分，在现存的人群中仍然大量存在。然而，这些微生物中的一小部分与其人类宿主之间的关系似乎随着时间的推移而发生了变化，它们最近分别作为胃肠道病原体和神经病原体而声名狼藉。另一方面，像军团菌属这样的环境微生物，由于人工生态系统的原因，最近宿主范围发生了变化，现在在工业化国家是一个主要问题。这种偶然现象涉及的其他变量可能是由于现代医学和生活方式，与人类相关的微生物多样性明显减少或减少。所有这些都可能导致以新出现的病原体形式出现更多的偶然病原体。
