Metal homeostasis in bacteria is a complex and delicate balance. While some metals such as iron and copper are essential for cellular functions, others such as cadmium and arsenic are inherently cytotoxic. While bacteria regularly encounter essential metals, exposure to high levels of toxic metals such as cadmium and arsenic is only experienced in a handful of special habitats. Nonetheless, Listeria and other Gram-positive bacteria have evolved an impressively diverse array of genetic tools for acquiring enhanced tolerance to such metals. Here we summarize this fascinating collection of resistance determinants in Listeria, with special focus on resistance to cadmium and arsenic, as well as to biocides and antibiotics. We also provide a comparative description of such resistance determinants and adaptations in other Gram-positive bacteria. The complex co-selection of heavy metal resistance and other types of resistance seems to be universal across the Gram-positive bacteria while the type of co-selected traits reflects the lifestyle of the specific microbe. The roles of heavy metal resistance genes in environmental adaptation and virulence appear to vary by genus, highlighting the need for further functional studies to explain the mystery behind the array of heavy metal resistance determinants dispersed and maintained among Gram-positive bacteria.

中文翻译：

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利斯特氏菌和其他革兰氏阳性细菌中镉和砷抗性决定因素的传播和保存。

细菌中的金属稳态是一个复杂而微妙的平衡。尽管某些金属（例如铁和铜）对于细胞功能至关重要，但其他金属（例如镉和砷）本身具有细胞毒性。尽管细菌经常遇到必需金属，但只有在少数特殊栖息地中才会接触到高水平的有毒金属，例如镉和砷。尽管如此，李斯特菌和其他革兰氏阳性细菌已经进化出令人印象深刻的多种遗传工具，以增强对此类金属的耐受性。在这里，我们总结了李斯特菌中一系列令人着迷的抗性决定因素，特别关注对镉和砷的抗性以及对杀生物剂和抗生素的抗性。我们还提供了在其他革兰氏阳性细菌中这种抗性决定簇和适应性的比较描述。重金属抗性和其他类型抗性的复杂共选择似乎在革兰氏阳性细菌中很普遍，而共选择性状的类型则反映了特定微生物的生活方式。重金属抗性基因在环境适应性和毒力中的作用似乎因属而异，强调需要进一步的功能研究以解释在革兰氏阳性细菌中分散和维持的重金属抗性决定簇阵列背后的奥秘。