There are 17+ studies on PubMed.
- “Parkinson’s disease reduced content of Dorea, Bacteroides, Prevotella, Faecalibacterium, Bacteroides massiliensis, Stoquefichus massiliensis, Bacteroides coprocola, Blautia glucerasea, Dorea longicatena, Bacteroides dorei, Bacteroides plebeus, Prevotella copri, Coprococcus eutactus, and Ruminococcus callidus, and increased content of Christensenella, Catabacter, Lactobacillus, Oscillospira, Bifidobacterium, Christensenella minuta, Catabacter hongkongensis, Lactobacillus mucosae, Ruminococcus bromii, and Papillibactercinnamivorans. ”  
- ” two genera belonging to the Clostridium leptum subgroup, Faecalibacteria and Papillibacter, display consistent patterns with respect to disease status and may thus serve as reliable ‘microbiomarkers’ for IBD. 
- “In general, the community changes induced by the three β-lactam antibiotics showed consistency in inhibiting Papillibacter, Prevotella and Alistipes while inducing massive growth of Clostridium”