Kanojiya Poonam, Haldar Tiyasa, Saroj Sunil D
Symbiosis School of Biological Sciences, Symbiosis International (Deemed University)Lavale, Pune, Maharashtra, 412115, India.
Arch Microbiol. 2025 Jan 29;207(2):46. doi: 10.1007/s00203-025-04249-8.
Environmental factors play a crucial role in bacterial virulence. During transmission, in a non-host environment bacteria are exposed to various environmental stress which could alter bacterial physiology and virulence. N. meningitidis is transmitted from person to person through direct contact. However, the role of environmental desiccation in the virulence of bacterial pathogens is not clearly understood. Therefore, the effect of environmental desiccation on survival, transmission, and virulence needs further investigation. We demonstrate that N. meningitidis was sensitive to desiccation stress. The viable counts reduced significantly (p < 0.05) after desiccation. It was found that desiccation induces a viable but non-culturable state (VBNC) in N. meningitidis. We considered cells to be in VBNC when no viable counts were obtained on growth media and live cells were detected after live-dead staining. After resuscitation, N. meningitidis retained virulence characteristics which indicate that it can transit between the host in VBNC state. Furthermore, the relative expression of capsule increased significantly after 12 and 24 h of desiccation. The observations indicate that the environmental desiccation might induce capsule biosynthesis in N. meningitidis, leading to enhanced virulence and survival in macrophages.
环境因素在细菌毒力中起着关键作用。在传播过程中，在非宿主环境中细菌会受到各种环境压力，这可能会改变细菌的生理特性和毒力。脑膜炎奈瑟菌通过直接接触在人与人之间传播。然而，环境干燥对细菌病原体毒力的作用尚不清楚。因此，环境干燥对生存、传播和毒力的影响需要进一步研究。我们证明脑膜炎奈瑟菌对干燥胁迫敏感。干燥后活菌数显著减少（p < 0.05）。研究发现干燥会诱导脑膜炎奈瑟菌进入活的但不可培养状态（VBNC）。当在生长培养基上未获得活菌数且经死活染色后检测到活细胞时，我们认为细胞处于VBNC状态。复苏后，脑膜炎奈瑟菌保留了毒力特征，这表明它可以在VBNC状态下在宿主之间传播。此外，干燥12小时和24小时后，荚膜的相对表达显著增加。这些观察结果表明，环境干燥可能会诱导脑膜炎奈瑟菌中的荚膜生物合成，从而导致其毒力增强和在巨噬细胞中的存活率提高。
