Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research highlights the involvement of L. monocytogenes plasmids in different stress response mechanisms, which contribute to its survival in food production facilities. Ultraviolet (UV) light in the UVC spectrum (200–280 nm) is used in food production to control microbial contamination. Although plasmid-encoded UV resistance mechanisms have been described in other bacteria, no research indicates that L. monocytogenes plasmids contribute to the UV stress response. The plasmids of L. monocytogenes strains 6179, 4KSM and R479a are genetically distinct and were utilized to study the roles of plasmids in the UV response. Wild-type and plasmid-cured variant cells were grown to logarithmic or late-stationary phase, plated on agar plates and exposed to UVC for 60 or 90 s, and colony-forming units (CFUs) were determined. CFUs of 6179 and 4KSM, bearing pLM6179 and p4KSM, respectively, were significantly (P-value < 0.05) higher than those of the plasmid-cured strains in both logarithmic and stationary phases. No difference in survival was observed for the R479a strain. Our data show for the first time that certain L. monocytogenes plasmids contribute to the survival of UVC light stress.

中文翻译：

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某些单核细胞增生李斯特菌质粒有助于增加 UVC 紫外线压力

单核细胞增生李斯特菌是高度致命的食源性疾病李斯特菌病的病原体，可以在食品生产环境中持续存在。最近的研究强调了单核细胞增生李斯特菌质粒参与不同的应激反应机制，这有助于其在食品生产设施中的生存。UVC 光谱（200–280 nm）中的紫外线 (UV) 用于食品生产以控制微生物污染。尽管在其他细菌中描述了质粒编码的紫外线抗性机制，但没有研究表明单核细胞增生李斯特菌质粒有助于紫外线应激反应。单核细胞增生李斯特菌的质粒菌株 6179、4KSM 和 R479a 在遗传上是不同的，用于研究质粒在紫外线反应中的作用。野生型和质粒治愈的变异细胞生长至对数期或后期稳定期，接种在琼脂平板上并暴露于 UVC 60 或 90 秒，并确定集落形成单位 (CFU)。分别带有 pLM6179 和 p4KSM 的 6179 和 4KSM 的 CFU 显着（P值 < 0.05）高于对数和固定相的质粒治愈菌株的CFU 。没有观察到 R479a 菌株的存活率差异。我们的数据首次显示某些单核细胞增生李斯特菌质粒有助于 UVC 光胁迫的存活。