Abstract
Although several studies have identified a distinct gut microbiota in individuals with acute ischemic stroke (AIS), there is a limited amount of research that has simultaneously investigated alterations in the oral and intestinal microbiota in AIS patients and their correlation with clinical prognosis. This was a prospective and observational single-center cohort study in which we included 160 AIS patients who were admitted within 24 h after a stroke event. We collected oral and rectal swab samples for analysis using 16S rRNA high-throughput sequencing. Our study revealed that patients with unfavorable outcomes after AIS showed early disruptions in their oral and intestinal microbiota. Rectal swabs showed increased levels of facultatively anaerobic bacteria in patients with a poor prognosis, while the oral cavity exhibited higher levels of anaerobic and opportunistic pathogenic bacteria. By employing machine learning analysis, we found that the microbiota composition at both rectal and oral sites could predict early and long-term outcomes. Moreover, patients with a poor prognosis displayed increased oral bacterial colonization in the rectal microbiota and altered interactions between the oral and gut microbiota. This study reveals distinct rectal and oral bacteria that could predict unfavorable outcomes for AIS patients. Monitoring the microbiota of various body sites during the early stages after admission may hold prognostic value and inform personalized treatment strategies. The presence of oral bacteria colonizing the intestines during the acute phase of stroke could serve as an early indication of poor outcomes for AIS patients.