Wozniak Hannah, Gaïa Nadia, Lazarevic Vladimir, Le Terrier Christophe, Beckmann Tal Sarah, Balzani Eleonora, Urner Martin, Pugin Jérôme, Schrenzel Jacques, Heidegger Claudia-Paula
Intensive Care Unit, Department of Acute Medicine, Geneva University Hospitals, Geneva, Switzerland.
Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada.
Ann Intensive Care. 2024 Nov 26;14(1):174. doi: 10.1186/s13613-024-01407-x.
Critical illness is associated with an altered gut microbiota, yet its association with poor outcomes remains unclear. This study evaluates the early gut microbiota diversity changes in intensive care unit patients and its association with mortality. Additionally, it explores fecal pH as a potential biomarker for these changes.
In this prospective observational cohort study, fecal samples were collected at two time points: S1, the first stool passed upon intensive care unit admission, and S2, the first stool passed at least 24 h after S1. Full-length 16S rRNA gene sequencing was performed for gut microbiota analysis, with α-diversity measured using the Shannon index. Bayesian joint models were used to estimate the association between time-varying changes in gut microbiota diversity and 60-day mortality, as well as the association between daily changes in stool pH and in diversity.
Twenty-four of 96 patients overall died during follow-up. Daily Shannon index decreased on average by -0.1 points [95% Credible Intervals (CrI) -0.20 to -0.10]. Every point decrease in Shannon index was associated with a 1.99-fold increase in the hazard of death (95% CrI, 1.04 to 4.51). Time-varying fecal pH levels were not associated with changes in Shannon index.
Gut microbiota diversity decreased over time, associated with increased mortality. Fecal pH is an unreliable marker of gut microbiota change. Future studies on gut microbiota and related biomarkers should focus on the initial days in the intensive care unit to detect and mitigate a decline in gut microbiota diversity.
危重病与肠道微生物群改变有关，但其与不良预后的关联仍不明确。本研究评估了重症监护病房患者早期肠道微生物群多样性的变化及其与死亡率的关联。此外，还探讨了粪便pH值作为这些变化的潜在生物标志物。
在这项前瞻性观察性队列研究中，在两个时间点采集粪便样本：S1，重症监护病房入院后排出的第一次粪便；S2，在S1之后至少24小时排出的第一次粪便。对肠道微生物群进行全长16S rRNA基因测序分析，使用香农指数测量α多样性。采用贝叶斯联合模型估计肠道微生物群多样性随时间变化与60天死亡率之间的关联，以及粪便pH值每日变化与多样性之间的关联。
96例患者中有24例在随访期间死亡。每日香农指数平均下降-0.1分[95%可信区间（CrI）-0.20至-0.10]。香农指数每下降1分，死亡风险增加1.99倍（95% CrI，1.04至4.51）。随时间变化的粪便pH值水平与香农指数的变化无关。
肠道微生物群多样性随时间下降，与死亡率增加有关。粪便pH值是肠道微生物群变化的不可靠标志物。未来关于肠道微生物群和相关生物标志物的研究应聚焦于重症监护病房的最初几天，以检测和减轻肠道微生物群多样性的下降。
