Gut Microbiome Signatures Predict ICU Delirium Risk in Mechanically Ventilated Older Adults
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Background: ICU delirium is a frequent neurological complication of critical illness, while emerging evidence suggests that intestinal dysbiosis may contribute to neurological vulnerability through microbiota-gut-brain interactions. Objective: To investigate the relationship between early gut microbiome characteristics and ICU delirium in mechanically ventilated adults aged ≥65 years. Methods: This analytical observational study included 85 mechanically ventilated older adults treated in tertiary-care ICUs in Punjab between September and December 2025. Fecal samples obtained within 48 hours of mechanical ventilation were analysed using 16S rRNA gene sequencing. Delirium was assessed twice daily using CAM-ICU. Microbial diversity and selected bacterial families were compared according to delirium status, followed by multivariable logistic regression adjusting for age, APACHE II score, and broad-spectrum antibiotic exposure. Results: Delirium occurred in 38/85 participants (44.7%). Shannon diversity was lower in participants with delirium than without delirium (2.14±0.45 vs 3.12±0.58; mean difference −0.98, 95% CI −1.20 to −0.76; p<0.001). Lachnospiraceae (4.2% vs 12.8%) and Ruminococcaceae (3.6% vs 9.4%) were depleted, whereas Enterococcaceae was increased (8.9% vs 2.4%). Higher Shannon diversity (aOR 0.35, 95% CI 0.18–0.68; p=0.003) and greater Lachnospiraceae abundance (aOR 0.78, 95% CI 0.64–0.94; p=0.011) were independently associated with lower odds of delirium. Conclusion: ICU delirium was associated with reduced microbial diversity and altered bacterial composition. These findings support further prospective validation of gut microbiome characteristics as potential markers of delirium vulnerability
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1. Fan YY, Luo RY, Wang MT, Yuan CY, Sun YY, Jing JY. Mechanisms underlying delirium in patients with critical illness. Front Aging Neurosci. 2024;16:1446523.
2. Dabrowski W, Siwicka-Gieroba D, Gasinska-Blotniak M, Zaid S, Jezierska M, Pakulski C, et al. Pathomechanisms of non-traumatic acute brain injury in critically ill patients. Medicina (Kaunas). 2020;56(9):469.
3. Xu X, Hu Y, Yan E, Zhan G, Liu C, Yang C. Perioperative neurocognitive dysfunction: thinking from the gut? Aging (Albany NY). 2020;12(15):15797.
4. Ticinesi A, Parise A, Nouvenne A, Cerundolo N, Prati B, Meschi T. The possible role of gut microbiota dysbiosis in the pathophysiology of delirium in older persons. Microbiome Res Rep. 2023;2(3):19.
5. Tan S, Chen W, Kong G, Wei L, Xie Y. Peripheral inflammation and neurocognitive impairment: correlations, underlying mechanisms, and therapeutic implications. Front Aging Neurosci. 2023;15:1305790.
6. Yong SJ. Long COVID or post-COVID-19 syndrome: putative pathophysiology, risk factors, and treatments. Infect Dis (Lond). 2021;53(10):737-754.
7. Corriero A, Gadaleta RM, Puntillo F, Inchingolo F, Moschetta A, Brienza N. The central role of the gut in intensive care. Crit Care. 2022;26(1):379.
8. Garcez FB, Garcia de Alencar JC, Fernandez SSM, Avelino-Silva VI, Sabino EC, Martins RCR, et al. Association between gut microbiota and delirium in acutely ill older adults. J Gerontol A Biol Sci Med Sci. 2023;78(8):1320-1327.
9. Park H, Lee CH. The impact of pulmonary disorders on neurological health (lung-brain axis). Int Neurourol J. 2024;24(3):e20.
10. Duve K, Petakh P, Kamyshnyi O. COVID-19-associated encephalopathy: connection between neuroinflammation and microbiota-gut-brain axis. Front Microbiol. 2024;15:1406874.
11. Lu X, Xue Z, Qian Y, Wei S, Qiao Y, Zhang W, et al. Changes in intestinal microflora and its metabolites underlie the cognitive impairment in preterm rats. 2022;12:945851.
12. Ling Z, Zhu M, Yan X, Cheng Y, Shao L, Liu X, et al. Structural and functional dysbiosis of fecal microbiota in Chinese patients with Alzheimer's disease. Front Cell Dev Biol. 2021;8:634069.
13. Ayten Ş, Bilici S. Modulation of gut microbiota through dietary intervention in neuroinflammation and Alzheimer's and Parkinson's diseases. Curr Nutr Rep. 2024;13(2):82-96.
14. Chaudhry TS, Senapati SG, Gadam S, Mannam HPSS, Voruganti HV, Abbasi Z, et al. The impact of microbiota on the gut-brain axis: examining the complex interplay and implications. 2023;12(16):5231.
15. Moustafa SA, Mohamed S, Dawood A, Azar J, Elmorsy E, Rizk NA, et al. Gut brain axis: an insight into microbiota role in Parkinson's disease. Metab Brain Dis. 2021;36(7):1545-1557.
16. Suresh SB, Malireddi A, Abera M, Noor K, Ansar M, Boddeti S, et al. Gut microbiome and its role in Parkinson's disease. 2024;16(11).
17. Xiao W, Su J, Gao X, Yang H, Weng R, Ni W, et al. The microbiota-gut-brain axis participates in chronic cerebral hypoperfusion by disrupting the metabolism of short-chain fatty acids. Microbiome. 2022;10(1):62.
18. Hu A, Zaongo SD, Harypursat V, Wang X, Ouyang J, Chen Y. HIV-associated neurocognitive disorder: key implications of the microbiota-gut-brain axis. Front Microbiol. 2024;15:1428239.
19. Chen Q, Shi J, Yu G, Xie H, Yu S, Xu J, et al. Gut microbiota dysbiosis in patients with Alzheimer's disease and correlation with multiple cognitive domains. 2024;16:1478557.
20. Borrego-Ruiz A, Borrego JJ. Neurodevelopmental disorders associated with gut microbiome dysbiosis in children. Children (Basel). 2024;11(7):796.