Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA.
Harvard Chan Microbiome in Public Health Center, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA.
Appl Environ Microbiol. 2021 Mar 11;87(7). doi: 10.1128/AEM.02924-20.
Perturbation of natural microbial communities by antimicrobials, such as triclosan, can result in selection for antibiotic tolerance, which is of particular concern when pathogens are present. Members of the genus are found in many natural microbial communities and frequently demonstrate increased abundance following triclosan exposure. The pathogen and well-studied model organism exhibits high triclosan tolerance; however, it is unknown if all species share this trait or if there are susceptible strains. We characterized the triclosan tolerance phenotypes of diverse isolates obtained from triclosan-exposed built environments and identified both tolerant and sensitive strains. High tolerance is associated with carriage of the enoyl-acyl carrier reductase (ENR) isozyme gene , compared to the lesser protective effects of efflux or presence of ENRs. Given its unique importance, we examined distribution throughout species using large-scale phylogenomic analyses. We find presence or absence is largely invariant at the species level but demonstrates multiple gain and loss events in its evolutionary history. We further provide evidence of its presence on mobile genetic elements. Our results demonstrate the surprising variability in triclosan tolerance in and confirm to be a useful indicator for high triclosan tolerance in These findings provide a framework for better monitoring of in triclosan-exposed environments and interpreting effects on species and gene composition. Closely related species are typically assumed to demonstrate similar phenotypes driven by underlying conserved genotypes. When monitoring for the effect of antimicrobials on the types of species that may be selected for, this assumption may prove to be incorrect, and identification of additional genetic markers may be necessary. We isolated several phylogenetically diverse members of from indoor environments and tested their phenotypic tolerance toward the commonly used antimicrobial triclosan. Although isolates are broadly regarded to be highly triclosan tolerant, we demonstrate the presence of both triclosan-tolerant and -susceptible strains, separated by a difference in tolerance of nearly 3 orders of magnitude. Bioinformatic and experimental investigation demonstrated that the presence of the gene was associated with high tolerance. We demonstrate that is not evenly distributed in all species and that its presence could be a useful predictor of high triclosan tolerance suitable for antimicrobial monitoring efforts involving triclosan.
抗生素（如三氯生）会扰乱自然微生物群落，导致抗生素耐药性的选择，而当病原体存在时，这尤其令人担忧。属的成员存在于许多自然微生物群落中，并且在暴露于三氯生后经常表现出丰度增加。病原体和研究充分的模式生物 表现出对三氯生的高度耐受性；然而，尚不清楚所有 物种是否都具有这种特性，或者是否存在敏感菌株。我们对从暴露于三氯生的建筑环境中获得的不同 分离株的三氯生耐受性表型进行了表征，并鉴定出了耐受和敏感菌株。与外排或存在 ENR 的保护作用较小相比，高耐受力与携带烯酰基辅酶 A 还原酶（ENR）同工酶基因 有关。鉴于其独特的重要性，我们使用大规模系统发育基因组学分析研究了 在 物种中的分布。我们发现 的存在或缺失在种水平上基本不变，但在其进化历史中表现出多次获得和丧失事件。我们进一步提供了其存在于移动遗传元件上的证据。我们的结果表明 在三氯生耐受性方面存在惊人的可变性，并证实 是 中三氯生高耐受性的有用指标。这些发现为更好地监测暴露于三氯生环境中的 提供了框架，并解释了其对物种和基因组成的影响。密切相关的物种通常被认为由于潜在的保守基因型而表现出相似的表型。在监测抗生素对可能被选择的物种类型的影响时，这种假设可能被证明是不正确的，可能需要确定其他遗传标记。我们从室内环境中分离出几种系统发育上多样化的 成员，并测试了它们对常用抗菌剂三氯生的表型耐受性。尽管 分离株被广泛认为具有高度的三氯生耐受性，但我们证明了存在对三氯生耐受和敏感的菌株，其耐受性差异近 3 个数量级。生物信息学和实验研究表明，基因 的存在与高耐受性有关。我们证明 并非均匀分布在所有 物种中，其存在可能是一种有用的预测因子，适用于涉及三氯生的抗菌监测工作。
