rUTI Resolution After FMT for Clostridioides difficile Infection: A Case Report.

Clostridioides difficile infection (CDI) is the leading cause of nosocomial infectious diarrhea. Fecal microbiota transplantation (FMT) is a successful treatment for recurrent CDI (rCDI), and in some patients FMT has been associated with the resolution of recurrent urinary tract infections (rUTI). Recent evidence suggests that the origin of most bacterial infections in the urinary tract is the gut. Thus, the possibility of using FMT to displace pathogens commonly involved in rUTIs has major therapeutic implications. We report the case of a 93-year-old female patient with a rCDI and rUTI that underwent FMT and reported a complete clinical resolution of CDI; unexpectedly, no new symptomatic UTI episodes were diagnosed post-FMT. We characterized the gut microbiota of the stool donor and of the patient before and after the procedure. Our patient presented a dysbiosis with clear predominance of Enterobacteriaceae (74%) before FMT, which was significantly reduced to 0.07% after FMT. These findings were maintained for almost a year. We also observed an increase in microbial diversity indices compared with the pre-FMT sample reaching diversity values comparable to the donor stool samples. We reasoned that the disappearance of UTIs in our patient resulted from the reduction of Enterobacteriaceae in the gut microbiota. Our findings support previous evidence suggesting the potential of FMT for rUTI, particularly in cases due to multi-drug resistant pathogens where conventional antibiotic treatment is not an option.