Table 2.

Summary of patient studies on gut microbiota in stroke.

Reference	Patient group	Participants enrollment	Outcome measures
Zhu et al. 2016 [111]	Plasma TMAO levels in subjects	>4000	The subject's plasma TMAO level independently predicted incident (3 years) risk of thrombosis (heart disease, stroke)
Yin et al. 2015 [142]	Patients with large-artery atherosclerotic ischemic stroke and transient ischemic attack	553	Patients with stroke and transient ischemic attack had more opportunistic pathogens, such as Enterobacter, macrophages, Oscillibacter, and Desulfovibrio, but fewer commensal or beneficial genera, such as Bacteroides, Prevotella, and Faecalibacterium, and had significantly lower TMAO levels
Swidsinski et al. 2012 [145]	Patients hospitalized in two stroke units	110	Typical for stroke was the migration of leukocyte into the mucus within 1–3 days; then, the main fermentative Roseburia, Bacteroides, and Faecalibacterium prausnitzii groups suddenly decontaminated and leukocytes in the stool disappeared; the arrest of bacterial fermentation between within 3–7 days; then Enterobacteriaceae, Bifidobacteriaceae, and Clostridium outnumbered Bacteroides, Roseburia, and Faecalibacterium prausnitzii, and after that declined to initial values
Yamashiro et al. 2017 [146]	Patients with acute ischemic stroke	81	The bacterial counts of Lactobacillus ruminis were significantly higher in stroke patients; ischemic stroke was independently associated with increased bacterial counts of Atopobium cluster and Lactobacillus ruminis, and decreased numbers of Lactobacillus sakei subgroup, and was associated with decreased and increased concentrations of acetic acid and valeric acid, respectively; changes in the prevalence of Lactobacillus ruminis were positively correlated with serum interleukin-6 levels
Ling et al. 2020 [147]	Patients with ischemic stroke	93	The abundance of Firmicutes and its members, including Clostridia, Clostridiales, Lachnospiraceae, and Lachnospiraceae_other, was significantly decreased in the age-matched poststroke cognitive impairment group; poststroke cognitive impairment was significantly correlated with the abundance of Enterobacteriaceae after adjustments
Haak et al. 2020 [148]	Patients with ischemic and hemorrhagic stroke	400	Disruption of intestinal communities during ischemic and hemorrhagic stroke; an enrichment of bacteria implicated in TMAO production and a loss of butyrate-producing bacteria; twofold lower plasma levels of TMAO; lower abundance of butyrate-producing bacteria within 24 h of hospital admission was an independent predictor of enhanced risk of poststroke infection
Xia et al. 2019 [149]	Patients with acute ischemic stroke	194	Eighteen genera were significantly different between stroke patients and healthy individuals; gut microbiota dysbiosis was significantly correlated with patients' outcome

TMAO: trimethylamine oxide.