Cardona Cesar, Lax Simon, Larsen Peter, Stephens Brent, Hampton-Marcell Jarrad, Edwardson Christian F, Henry Chris, Van Bonn Bill, Gilbert Jack A
Graduate Program in Biophysical Sciences, University of Chicago, Chicago, Illinois, USA.
Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA.
mSystems. 2018 May 29;3(3). doi: 10.1128/mSystems.00052-18. eCollection 2018 May-Jun.
Host-associated microbial dynamics are influenced by dietary and immune factors, but how exogenous microbial exposure shapes host-microbe dynamics remains poorly characterized. To investigate this phenomenon, we characterized the skin, rectum, and respiratory tract-associated microbiota in four aquarium-housed dolphins daily over a period of 6 weeks, including administration of a probiotic during weeks 4 to 6. The environmental bacterial sources were also characterized, including the animals' human handlers, the aquarium air and water, and the dolphins' food supply. Continuous microbial exposure occurred between all sites, yet each environment maintained a characteristic microbiota, suggesting that the majority of exposure events do not result in colonization. Small changes in water physicochemistry had a significant but weak correlation with change in dolphin-associated bacterial richness but had no influence on phylogenetic diversity. Food and air microbiota were the richest and had the largest conditional influence on other microbiota in the absence of probiotics, but during probiotic administration, food alone had the largest influence on the stability of the dolphin microbiota. Our results suggest that respiratory tract and gastrointestinal epithelium interactions with air- and food-associated microbes had the biggest influence on host-microbiota dynamics, while other interactions, such as skin transmission, played only a minor role. Finally, direct oral stimulation with a foreign exogenous microbial source can have a profound effect on microbial stability. These results provide valuable insights into the ecological influence of exogenous microbial exposure, as well as laying the foundation for improving aquarium management practices. By comparing data for dolphins from aquaria that use natural versus artificial seawater, we demonstrate the potential influence of aquarium water disinfection procedures on dolphin microbial dynamics.
宿主相关的微生物动态受饮食和免疫因素影响，但外源性微生物暴露如何塑造宿主-微生物动态仍知之甚少。为了研究这一现象，我们在6周的时间里每天对4只饲养在水族馆的海豚的皮肤、直肠和呼吸道相关微生物群进行了特征分析，包括在第4至6周期间施用益生菌。还对外源性细菌来源进行了特征分析，包括动物的人类饲养员、水族馆的空气和水以及海豚的食物供应。所有部位之间都存在持续的微生物暴露，但每个环境都维持着独特的微生物群，这表明大多数暴露事件不会导致定植。水的物理化学性质的微小变化与海豚相关细菌丰富度的变化存在显著但微弱的相关性，但对系统发育多样性没有影响。在不使用益生菌的情况下，食物和空气微生物群最为丰富，对其他微生物群的条件影响最大，但在施用益生菌期间，仅食物对海豚微生物群的稳定性影响最大。我们的结果表明，呼吸道和胃肠道上皮与空气和食物相关微生物的相互作用对宿主-微生物群动态影响最大，而其他相互作用，如皮肤传播，只起次要作用。最后，用外来的外源性微生物源进行直接口服刺激可对微生物稳定性产生深远影响。这些结果为外源性微生物暴露的生态影响提供了有价值的见解，也为改善水族馆管理实践奠定了基础。通过比较来自使用天然海水和人工海水的水族馆的海豚的数据，我们证明了水族馆水消毒程序对海豚微生物动态的潜在影响。
