Preferred Reporting Items for Microbiotherapy (PRIM) Guidelines Across Medical Disciplines: An International Delphi Consensus

Microbiotherapy has opened new avenues for managing dysbiosis-related diseases. However, many studies did not cover all the necessary reporting items for microbiotherapy making the interpretation of results, safety assessment, technology extension, and even the transparency of legitimacy difficult. This project consisted of 2 phases. First, we proposed an initial preferred reporting items for microbiotherapy (PRIM) checklist and applied it to oncology studies from 2011 to 2023 according to Meta-Analyses guideline. Only 39.3% (n = 64) of these studies (n = 163) met all PRIM checklist items. The culture-based microbiotherapy (CMT) studies had higher score than non-culture-based (NMT) ones (p = 0.018). In the second phase, the expert panel consisting of 22 specialists from eight countries across Asia, Australia, Europe, and North America refined and finalized the PRIM guidelines (named as PRIM 2024) through Delphi consensus. The PRIM 2024 guidelines conclude 10 statements and 18 points on diagnosis, delivery route, source, classification, preparation, dosage, state, concomitant treatment, efficacy, and safety. The panel defined less than 80% of all PRIM points (14 points) as low-quality reports. These guidelines are recommended for reporting on microbiotherapy in clinical studies and reports on compassionate use, including but not limited to fecal microbiota transplantation, phage therapy, probiotics, and synbiotics. These consistent and transparent reporting items can help researchers and practitioners better evaluate, compare, implement research findings in microbiotherapy.