Association between enterotypes of the gut microbiota and features of stroke

Background An enterotype (e.g., genera Bacteroides and Prevotella ) is a classification of patients’ gut microbes into three types, and these types differ in their features of cardiovascular disease. We hypothesized that patients have different enterotypes depending on their arteriosclerosis risk factors, stroke subtype, and severity of stroke. Methods Stool specimens were collected from 100 patients (age: 73.4 ± 11.3 years, 62 men, 38 women) with ischemic stroke after consent was obtained. Data on age, sex, risk of arteriosclerosis, stroke subtype, history of stroke, neurological severity at admission, and prognosis were obtained from the patients’ medical records. Phylogenetic analyses of the 16S rRNA gene (V3–V4 region) extracted from each stool sample were performed. Quantitative analyses of the presence of each bacterial genus in the intestines were performed using a next-generation sequencer. After the number of each genus of gut microbes was extracted, ≥ 30% of the patients with the genus Bacteroides were classified as type I, ≥ 15% with the genus Prevotella were classified as type II, and the rest were classified as type III. We analyzed the association between the patients’ enterotypes and their characteristics (i.e., arteriosclerosis risk factors such as stroke subtype, and severity of stroke). Results Thirty-three patients had type I, 10 had type II, and 57 had type III, with no overlap. Patients with types I and II had a lower prevalence of dyslipidemia than those with type III (types I vs II vs III: 36% vs 20% vs 58%, P = 0.028), a lower National Institute of Health and Stroke Scale score at admission (1 vs 1 vs 4 [median], P = 0.025), and the modified Rankin Scale score at discharge tended to be lower (1 vs 1 vs 2 [median], P = 0.094). Conclusions The enterotype may affect the risk factors and severity of ischemic stroke.