Identification of p‐cresol sulfate and secondary bile salts in human urine as sensitive biomarkers of fecal microbiota transplantation in R‐CDI patients

Abstract

Fecal microbiota transplantation (FMT) has become an effective therapy for recurrent Clostridium difficile infection (R‐CDI). Besides reestablishing a normal intestinal microbiome that offers better resistance to R‐CDI, the introduction of microflora from healthy donors through FMT is also expected to change the metabolomes in the intestine and the whole body due to diverse metabolic activities of transplanted microbiota. Therefore, monitoring the metabolic changes in biofluids and excretes provides the opportunities for identifying noninvasive biomarkers of microbial recolonization and understanding the metabolic influences of FMT on host and microflora. In this study, FMT‐induced metabolic changes were examined by the metabolomic comparison of pre‐FMT and post‐FMT urine samples from 18 R‐CDI patients who had symptoms rapidly resolved after receiving FMT from two donors. After the liquid chromatography‐mass spectrometry (LC‐MS) analysis of urine samples from the patients and the donors, the LC‐MS data were processed by partial‐least squares‐discriminant analysis (PLS‐DA), leading to the establishment of a multivariate model revealing the separation between pre‐ and post‐FMT urine samples as well as the similarity between post‐FMT and donor samples. Among a group of urinary metabolites affected by the FMT, the most prominent biomarkers are p‐cresol sulfate and secondary bile acid conjugates, which were absent in most pre‐FMT samples, but dramatically increased in the post‐FMT samples. The presence of p‐cresol sulfate and secondary bile acid conjugates in urine after FMT reflected the recovery of microfloral metabolism on tyrosine and primary bile acids in R‐CDI patients. Their levels in urine may function as effective and sensitive therapeutic indicators of the readiness of CDI patient for FMT as well as the recolonization of healthy microfloral colonies after FMT.Support or Funding InformationNIAID grant R21 AI114722 and NIFA project MIN‐18‐092