Abstract: Objective To explore the differences in gut virome and microbiome between patients with stroke and healthy volunteers. Methods Fifteen patients with acute ischemic stroke treated in the Department of Neurology of Nanfang Hospital between February, 2014 and February, 2016 and 15 healthy volunteers matched for age and sex were enrolled in this study. Virome sequencing and 16S rRNA sequencing were performed on stool samples of all the participants, and the composition and structures of the virome and microbiome were compared between the two groups. Results No significant difference was found in the overall diversity of virome between the stroke patients and the healthy volunteers (alpha diversity: P=0.320; beta diversity: P=0.169, R2=0.037), but virome composition differed significantly between the two groups. The relative abundance of Bacteroides phage B40_8 and Cronobacter phage CS01 increased significantly in patients with stroke. The structures and composition of the microbiome in patients with stroke also differed significantly from those of the healthy volunteers (alpha diversity: P=0.950; beta diversity: P=0.005, R2=0.117). The relative abundance of Megasphaera increased while that of Bifidobacterium decreased in patients with stroke. Correlation analysis showed that in the virome of stroke patients, the relative abundance of the phage preying Streptococcus was positively correlated with that of their hosts (r=0.550, P=0.036), while in the virome of healthy volunteers, the relative abundance of the phage preying Faecalibacterium (r=0.520, P=0.049), Bilophila (r=0.541, P=0.040) and Roseburia (r=0.526, P=0.046) were positively correlated with that of their respective hosts. Conclusion Stroke patients have similar overall diversity of the virome to healthy volunteers but different virome composition and interaction patterns between the virome and microbiome. The gut microbiome also differs between stroke patients and healthy volunteers. The relative abundance of opportunistic pathogens increases but that of symbiotic bacteria decreases in stroke patients.

Key words: gut microbiome; virome; stroke; bacteriophage