Authors

L E Peachey⁵; T P Jenkins⁵; N Ajami¹; ²; A S MacDonald⁶; M H Hsieh³; P Brindley⁴; C Cantacessi⁵; G Rinaldi⁷;  ¹ Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, UK;  ² Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, United States;  ³ Biomedical Research Institute, Rockville, Maryland, United States;  ⁴ George Washington University, United States;  ⁵ University of Cambridge, UK;  ⁶ University of Manchester, UK;  ⁷ Wellcome Trust Sanger Institute, UK

Discussion

Schistosomiasis is one of the most prevalent neglected tropical diseases. In spite of the extensive contribution of intestinal, liver and urogenital disease, little is known of the impact of schistosomes (blood flukes) on the composition of the commensal microbial flora of the vertebrate host. In particular, bacterial taxa with putative roles in the pathophysiology and immunology of schistosome infection and disease have yet to be identified. In this study, we characterised fluctuations in the composition of the microbial flora of the murine small (SI) and large intestine (LI) at two time-points, day 28 (D28) and day 50 (D50) post-infection with cercariae of Schistosoma mansoni. Bioinformatics analyses of microbial community high-throughput sequence data revealed an overall reduction in alpha diversity of the gut microbiome in S. mansoni-infected mice at D50 post-infection (SI P=0.006; LI P=0.02), alongside a significant increase in microbial beta diversity (SI P=0.004; LI P=0.008). Microbial composition analyses between groups showed expanded populations of Akkermansia muciniphila (phylum Verrucomicrobia) in the SI and LI of S. mansoni-infected mice at D28 and D50. Conversely, lactobacilli increased at D28 in the LI of S. mansoni infected mice, whilst at D50, infection was associated with changes in the relative abundance of a number of taxa. Amongst these, Turicibacterales were markedly reduced in the schistosome-infected mice compared with the uninfected counterparts. These findings demonstrate a significant dysbiosis in the gut microbial flora of mice at D50 post-infection with S. mansoni, at which time, parasite eggs are migrating across the intestinal wall. Observations of this study support a role for gut microbiota in the pathophysiology of schistosomiasis, and set a basis for future investigations of the mechanisms underlying the complex relationships among infection with parasitic worms, commensal flora, host immunity and disease outcome.