Fecal Microbiota Transplantation for Recurrent Infections in a Cystic Fibrosis Child Previously Screen Positive, Inconclusive Diagnosis (CFSPID): A Case Report.

infection (CDI) is generally treated with vancomycin, metronidazole or fidaxomicin, although fecal microbiota transplantation (FMT) represents a promising therapeutic option for antibiotic-resistant recurrent infections (rCDIs) in adults. In pediatric cystic fibrosis (CF) patients, CDIs are generally asymptomatic and respond to treatment. Here, we present the case of an 8-year-old female, initially diagnosed as "CFTR-related metabolic syndrome/cystic fibrosis screen positive, inconclusive diagnosis" (CMRS/CFSPID), who then progressed to CF at 12 months. In the absence of CF-related symptoms, she presented multiple and disabling episodes of bloody diarrhoea with positive tests for antigen and A/B toxin. After conventional treatments failed and several CDI relapses, FMT was proposed. Donor screening and GM donor-receiver matching identified her mother as a donor. Metataxonomy and targeted metabolomics provided, through a pre- and post-FMT time course, gut microbiota (GM) profiling to assess GM engraftment. At first, the GM map revealed severe dysbiosis, with a prevalence of Bacteroidetes and Proteobacteria (i.e., spp., ), a reduction in Firmicutes, a GM nearly entirely composed of Enterococcaceae (i.e., ) and an almost complete depletion of Verrucomicrobia and Actinobacteria, mostly represented by . Post FMT, an increment in spp. and spp. with a decrease in restored intestinal eubiosis. Consistently, four weeks after FMT treatment, the child's gut symptoms cleared, without CDI recurrence.