Listeria monocytogenes Source Distribution Analysis Indicates Regional Heterogeneity and Ecological Niche Preference among Serotype 4b Clones.
Listeria monocytogenes Source Distribution Analysis Indicates Regional Heterogeneity and Ecological Niche Preference among Serotype 4b Clones.
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DOI：
10.1128/mbio.00396-18
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发表时间：
2018-04-17
期刊：
影响因子：
6.4
通讯作者：
Kathariou S
中科院分区：
文献类型：
--
作者：
Lee S;Chen Y;Gorski L;Ward TJ;Osborne J;Kathariou S
最近对食源性病原体单增李斯特菌的生物多样性分析揭示了四种血清型 4b 主要高毒力克隆复合体 (CC)，即 CC1、CC2、CC4 和 CC6。与食物相比，人类临床分离株中这些克隆以及整个血清型 4b 的比例过高，表明具有高毒力。然而，有关不同地区血清型 4b 克隆之间潜在来源依赖性划分的数据很少。我们分析了主要来自北美的 347 个血清型 4b 分离株，以确定克隆在人类、其他动物、食物和水中的分布。 CC1、CC2、CC4 和 CC6 占主导地位，但令人惊讶的是，只有三个克隆，即 CC2 和单序列类型 (ST) ST382 和 ST639，表现出显着的来源依赖性关联，与其他来源相比，对食物 (CC2) 或水 (ST382 和 ST639) 的倾向更高。人类和食物分离株之间的配对比较发现，CC4 是人类分离株中唯一显着过高的血清型 4b 克隆。我们的分析还揭示了北美出现的几种血清型 4b 克隆。两个这样的新兴克隆，ST382（自 2014 年以来参与了几次疫情爆发）和 ST639，主要出现在人类和水分离株中。研究结果表明，尽管 CC1、CC2、CC4 和 CC6 普遍存在，但血清型 4b 的区域异质性比之前的推测要大得多。即使对一个地区的大型菌株组进行分析，也可能无法充分预测其他地区特有的和出现的克隆。血清型 4b 克隆复合体在生态位偏好方面可能有所不同，这表明需要进一步阐明储存库和载体，特别是对于新兴克隆。在单核细胞增生李斯特氏菌中，血清型 4b 菌株是导致人类疾病的主要因素，但不同来源和地区之间的血清型内分布仍不清楚。对来自四个不同来源（主要来自北美）的 347 个血清型 4b 分离株的分析证实了主要克隆 CC1、CC2、CC4 和 CC6 的总体优势，但发现只有 CC4 与人类疾病显着相关，而 CC2 与食物显着相关。值得注意的是，在来自北美的人类分离株中发现了几个新出现的克隆，其中一些还表现出对地表水的倾向。后者包括单克隆体 ST382（自 2014 年以来在美国多次爆发）和 ST639。这些克隆在来自其他地区的更大的样本组中明显代表性不足。尽管暂时与北美相关，但它们最终可能通过食品贸易或其他场所在全球传播。
Biodiversity analysis of the foodborne pathogen Listeria monocytogenes recently revealed four serotype 4b major hypervirulent clonal complexes (CCs), i.e., CC1, CC2, CC4, and CC6. Hypervirulence was indicated by overrepresentation of these clones, and serotype 4b as a whole, among human clinical isolates in comparison to food. However, data on potential source-dependent partitioning among serotype 4b clones in diverse regions are sparse. We analyzed a panel of 347 serotype 4b isolates, primarily from North America, to determine the distribution of clones in humans, other animals, food, and water. CC1, CC2, CC4, and CC6 predominated, but surprisingly, only three clones, i.e., CC2 and the singleton sequence types (STs) ST382 and ST639, exhibited significant source-dependent associations, with higher propensity for food (CC2) or water (ST382 and ST639) than other sources. Pairwise comparisons between human and food isolates identified CC4 as the only serotype 4b clone significantly overrepresented among human isolates. Our analysis also revealed several serotype 4b clones emerging in North America. Two such emerging clones, ST382 (implicated in several outbreaks since 2014) and ST639, were primarily encountered among human and water isolates. Findings suggest that in spite of the ubiquity of CC1, CC2, CC4, and CC6, regional heterogeneity in serotype 4b is substantially larger than previously surmised. Analysis of even large strain panels from one region may not adequately predict clones unique to, and emerging in, other areas. Serotype 4b clonal complexes may differ in ecological niche preference, suggesting the need to further elucidate reservoirs and vehicles, especially for emerging clones. In Listeria monocytogenes, serotype 4b strains are leading contributors to human disease, but intraserotype distributions among different sources and regions remain poorly elucidated. Analysis of 347 serotype 4b isolates from four different sources, mostly from North America, confirmed the overall predominance of the major clones CC1, CC2, CC4, and CC6 but found that only CC4 was significantly associated with human disease, while CC2 was significantly associated with food. Remarkably, several emerging clones were identified among human isolates from North America, with some of these also exhibiting a propensity for surface water. The latter included the singleton clones ST382, implicated in several outbreaks in the United States since 2014, and ST639. These clones were noticeably underrepresented among much larger panels from other regions. Though associated with North America for the time being, they may eventually become globally disseminated through the food trade or other venues.