Spatial Variation and Survival of Salmonella enterica Subspecies in a Population of Australian Sleepy Lizards (Tiliqua rugosa)
Spatial Variation and Survival of Salmonella enterica Subspecies in a Population of Australian Sleepy Lizards (Tiliqua rugosa)
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澳大利亚瞌睡蜥蜴（Tiliqua rugosa）种群中肠沙门氏菌亚种的空间变异和生存
DOI：
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发表时间：
2015
影响因子：
4.4
通讯作者：
David M. Gordon
中科院分区：
文献类型：
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作者：
S. Parsons;C. Michael Bull;David M. Gordon
许多肠道细菌的生命周期需要在两种截然不同的环境之间过渡。它们的主要栖息地是宿主的胃肠道，而在从一个宿主传播到另一个宿主的过程中，它们的次要栖息地是宿主外部的环境，如土壤、水和沉积物。因此，宿主和环境因素共同塑造肠道细菌种群的遗传结构。本研究在南澳大利亚半干旱地区的一种嗜睡蜥蜴（Tiliqua rugosa）种群中检测了四种肠道沙门氏菌亚种的分布。研究人员对生活在1920米乘720米研究区域内的蜥蜴进行了无线电跟踪，并在它们的活动季节（2001年、2002年和2006年）定期取样它们的肠道细菌。肠链球菌的6个亚种中有4个存在于该种群中，并且在蜥蜴中非随机分布。特别是肠球菌亚种。diarizonae仅限于生活在研究地点最阴暗的部分，上面有木麻黄树。研究肠球菌细胞在半自然条件下存活的实验表明，细胞存活率随着温度升高和紫外线照射的增加而下降。在测试的三个肠球菌亚种中，肠球菌亚种。Diarizonae的平均预期寿命一直比其他两个亚种短。在个体寄主内，肠链球菌亚种间不存在竞争优势等级。因此，肠链球菌亚种在该种群中的非随机分布似乎是由它们在外部环境中的不同生存特征驱动的。
ABSTRACT The life cycles of many enteric bacterial species require a transition between two very distinct environments. Their primary habitat is the gastrointestinal tract of the host, while their secondary habitat, during transmission from one host to another, consists of environments external to the host, such as soil, water, and sediments. Consequently, both host and environmental factors shape the genetic structure of enteric bacterial populations. This study examined the distribution of four Salmonella enterica subspecies in a population of sleepy lizards, Tiliqua rugosa, in a semiarid region of South Australia. The lizards living within the 1,920-m by 720-m study site were radio tracked, and their enteric bacteria were sampled at regular intervals throughout their active seasons in the years 2001, 2002, and 2006. Four of the six subspecies of S. enterica were present in this population and were nonrandomly distributed among the lizards. In particular, S. enterica subsp. diarizonae was restricted to lizards living in the most shaded parts of the study site with an overstorey of Casuarina trees. Experiments undertaken to investigate the survival of S. enterica cells under seminatural conditions revealed that cell survival decreased with increased exposure to elevated temperatures and UV light. Among the three S. enterica subspecies tested, S. enterica subsp. diarizonae consistently had an average expected life span that was shorter than that observed for the other two subspecies. There was no indication in the data that there was any competitive dominance hierarchy among the S. enterica subspecies within individual hosts. Thus, the nonrandom distribution of S. enterica subspecies in this population of lizards appears to be driven by their different survival characteristics in the external environment.