Effect of bacterial species treatment on EAE severity

This is a part of a study where, B6 mice were with specific bacteria enriched in multiple sclerosis patients and healthy controls. PC (P. copri DSM18205) and one of the predominant Blautia species in the human gut, B. wexlerae (DSM19850) (BW) were obtained from DSMZ. Phoeciola vulgatus (PV) was used as a control treatment as it contributed the most in the MSHC cluster. PV was cultured in house from healthy human fecal samples and confirmed using 16S rRNA sanger sequencing. Starting one week prior to the experiment, the gut microbiota was normalized among the groups by daily mixing cage bedding. Following this, all groups of mice underwent a short antibiotic cocktail treatment on days 6, 7, and 8 to create a conducive colonizing environment, followed by treatment with PC, PV or BW on days 9, 10, and 11. Subsequently, to determine the effect of PC, PV or BW on structuring gut microbial community, each group received two doses of healthy human fecal sample containing diverse microbiota on day 13 and 14. Fecal samples used for quantifying fecal biomarkers and fecal DNA was sequenced by amplifying 16S rRNA gene. Fecal samples collected at the end of the experiment (day 27) showed that fecal lipocalin-2 and calprotectin levels were significantly higher in mice administered BW compared to both those given PC or PV suggesting gut dysbiosis and higher gut inflammation in BW-administered mice. The changes in the gut microbiota was compared and on day 27 (end point) PC-administered mice had significantly higher abundances of Bacteroidota and lower levels of Desulfobacterota, Proteobacteria, and Verrucomicrobiota compared to the other two groups. However, the BW-administered group had significantly higher levels of Proteobacteria and Verrucomicrobiota whereas the PV-administered group had significantly higher levels of Desulfobacterota, Actinobacteriota and Firmicutes. At the genus level there were 26 taxa that were abundant at different levels between three groups. Bacteroides, Clostridum_sensu-stricto_1, Turicibacter, Marvinbryantia, Enterococcus, Rombutsia and Merdibacter were enriched in the PC-administered group, Akkermansia, Parasutterella and Coriobacteriaceae_UCG-002 were enriched in the BW-administered group, and 17 other genera including Parabacteroides, Adlercreutizia and Butyricimonas were enriched in the PV-administered group. This shows that specific bacteria enriched in MS patients when administered to mice alter gut microbiota and produce higher pro-inflammatory environment in the gut.