UCD Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland
UCD Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland.
Appl Environ Microbiol. 2019 Jan 23;85(3). doi: 10.1128/AEM.01993-18. Print 2019 Feb 1.
is a xerotolerant neonatal pathogen epidemiologically linked to powdered infant food formula, often resulting in high mortality rates. Here, we used transcriptome sequencing (RNA-seq) to provide transcriptional insights into the survival of in desiccated conditions. Our RNA-seq data show that about 22% of the total genes were significantly upregulated and 9% were downregulated during desiccation survival. When reverse transcription-quantitative PCR (qRT-PCR) was used to validate the RNA-seq data, we found that the primary desiccation response was gradually downregulated during the tested 4 hours of desiccation, while the secondary response remained constitutively upregulated. The 4-hour desiccation tolerance of was dependent on the immediate microenvironment surrounding the bacterial cell. The removal of Trypticase soy broth (TSB) salts and the introduction of sterile infant formula residues in the microenvironment enhanced the desiccation survival of SP291. The trehalose biosynthetic pathway encoded by and , a prominent secondary bacterial desiccation response, was highly upregulated in desiccated SP291 Δ was significantly inhibited compared with the isogenic wild type in an 8-hour desiccation survival assay, confirming the physiological importance of trehalose in desiccation survival. Overall, we provide a comprehensive RNA-seq-based transcriptional overview along with confirmation of the phenotypic importance of trehalose metabolism in during desiccation. is a pathogen of importance to neonatal health and is known to persist in dry food matrices, such as powdered infant formula (PIF) and its associated production environment. When infections are reported in neonates, mortality rates can be high. The success of this bacterium in surviving these low-moisture environments suggests that species can respond to a variety of environmental signals. Therefore, understanding those signals that aid the persistence of this pathogen in these ecological niches is an important step toward the development of strategies to reduce the risk of contamination of PIF. This research led to the identification of candidate genes that play a role in the persistence of this pathogen in desiccated conditions and, thereby, serve as a model target to design future strategies to mitigate PIF-associated survival of .
是一种耐干燥的新生病原体，在流行病学上与粉状婴儿配方食品有关，常导致高死亡率。在这里，我们使用转录组测序（RNA-seq）为在干燥条件下的生存提供转录见解。我们的 RNA-seq 数据显示，在干燥生存过程中，大约 22%的总基因显著上调，9%下调。当使用逆转录定量 PCR（qRT-PCR）验证 RNA-seq 数据时，我们发现主要的干燥响应在测试的 4 小时干燥过程中逐渐下调，而次要响应保持组成型上调。4 小时的干燥耐受性取决于细菌细胞周围的即时微环境。去除胰蛋白酶大豆肉汤（TSB）盐并在微环境中引入无菌婴儿配方残留物增强了 SP291 的干燥生存能力。由 和 编码的海藻糖生物合成途径，一种突出的二次细菌干燥响应，在干燥的 SP291 中高度上调。与同基因野生型相比，在 8 小时干燥生存试验中，缺失突变体的干燥生存能力显著受到抑制，证实了海藻糖在干燥生存中的生理重要性。总体而言，我们提供了基于 RNA-seq 的全面转录概述，并确认了海藻糖代谢在干燥过程中对 的表型重要性。是一种对新生儿健康很重要的病原体，已知在干粉状基质（如粉状婴儿配方食品（PIF）及其相关生产环境）中存在。当在新生儿中报告感染时，死亡率可能很高。这种细菌在这些低湿度环境中生存的成功表明， 物种可以对各种环境信号做出反应。因此，了解有助于该病原体在这些生态位中持续存在的那些信号是朝着制定降低 PIF 相关生存风险的策略迈出的重要一步。这项研究确定了在干燥条件下有助于该病原体持续存在的候选基因，从而为设计未来的策略来减轻与 PIF 相关的生存提供了模型目标。
