This is a rare one to be seen with CFS
There are 8+ studies on PubMed, many dealing with fish.
- ” According to 16S rRNA gene sequencing, Romboutsia spp. and C. difficile are closely related (>95% sequence identity).” 
- “DiCQAs (from ku ding cha tea) increased the relative abundances of Alistipes, Bacteroides, Bifidobacterium, Butyricimonas, Clostridium sensu stricto, Escherichia/Shigella, Parasutterella, Romboutsia, Oscillibacter, Veillonella, Phascolarctobacterium, Lachnospiracea incertae sedis, Gemmiger, Streptococcus, and Haemophilus and decreased the relative abundances of Ruminococcus, Anaerostipes, Dialister, Megasphaera, Megamonas, and Prevotella. ”