Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity
Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity
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DOI：
10.1098/rspb.2016.1553
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发表时间：
2016-09-28
影响因子：
4.7
通讯作者：
McKenzie, Valerie J.
中科院分区：
文献类型：
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作者：
Kueneman, Jordan G.;Woodhams, Douglas C.;McKenzie, Valerie J.
宿主相关的微生物组执行许多有益的功能，包括抵抗病原体和训练免疫系统。在这里，我们表明，两栖动物在圈养发展失去了大量的皮肤细菌的多样性，主要是由于减少持续输入的环境来源。我们将野生和圈养两栖动物的研究与超过1000种菌株的数据库相结合，使我们能够检查皮肤微生物组的抗真菌功能。我们追踪了62只濒危北方蟾蜍Anaxyrus boreas的皮肤细菌群落，跨越18个时间点，4种益生菌治疗，以及两次暴露于圈养的致命真菌病原体Batrachochytrium dendrobaeum（Bd），并将这些与从相同生命阶段的野生种群中收集的33个样本进行了比较。随着时间的推移，圈养的两栖动物失去了Bd抑制细菌，在随后的暴露中，暴露于Bd的个体感染的比例从33%上升到100%。在第二次Bd挑战期间，接种Bd抑制性益生菌Janthinobacterium lividum导致存活率增加40%，表明微生物组消耗的影响通过恢复Bd抑制性细菌是可逆的。总之，这项研究强调了皮肤相关细菌的持续环境输入在减轻破坏性两栖动物病原体方面的功能作用，并且长期圈养会降低这种防御功能。
Host-associated microbiomes perform many beneficial functions including resisting pathogens and training the immune system. Here, we show that amphibians developing in captivity lose substantial skin bacterial diversity, primarily due to reduced ongoing input from environmental sources. We combined studies of wild and captive amphibians with a database of over 1 000 strains that allows us to examine antifungal function of the skin microbiome. We tracked skin bacterial communities of 62 endangered boreal toads, Anaxyrus boreas, across 18 time points, four probiotic treatments, and two exposures to the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) in captivity, and compared these to 33 samples collected from wild populations at the same life stage. As the amphibians in captivity lost the Bd-inhibitory bacteria through time, the proportion of individuals exposed to Bd that became infected rose from 33% to 100% in subsequent exposures. Inoculations of the Bd-inhibitory probiotic Janthinobacterium lividum resulted in a 40% increase in survival during the second Bd challenge, indicating that the effect of microbiome depletion was reversible by restoring Bd-inhibitory bacteria. Taken together, this study highlights the functional role of ongoing environmental inputs of skin-associated bacteria in mitigating a devastating amphibian pathogen, and that long-term captivity decreases this defensive function.