Fecal Microbiome Transplantation (FMT) in Pediatric Patients Colonized With Antibiotic-resistant Pathogens Before Hematopoietic Stem Cell Transplantation (HSCT)

Recipients Inclusion Criteria: 1. detection by microbiology culture in any localization species of: * Pseudomonas aeruginosa * Clostridium difficile * Vancomycin-resistant Enterococcus * Streptococcus viridans * ESBL Enterobacteriaceae, including Escherichia coli and Klebsiella pneumoniae * Stenotrophomonas maltophilia * Acinetobacter * Methicillin-resistant Staphylococcus aureus 2. Indications for allo-HSCT Exclusion Criteria: 1. indications for therapy with antibiotics for the next 7 days after FMT 2. Nonstable condition during 1 week before FMT 3. Therapy with antibiotics less than 48 hours before FMT 4. Age less than 3 years 5. Neutrophils count \< 0,5 K/mcL at FMT day and\\or predicted decrease during 2 days after Donors (healthy volunteers) Inclusion Criteria: 1. Age 3-50 years old 2. Donor choosing order in the absence of contraindications: 1\) HLA-match/mismatch HSCT family donor; 2) Closest family relative with whom the recipient lives; 3) Unrelated healthy volunteer from the FRCC PCM bank of frozen transplants Exclusion Criteria: 1. Presens of: * ESBL Esherihia coli * Klebsiella pneumoniae * Pseudomonas aeruginosa * Clostridium difficile * MRSA * VRE * Streptococcus viridans * ESBL Enterobacteriaceae * Stenotrophomonas maltophilia * Acinetobacter in feces by microbiology culture assay 2. Therapy with antibiotics less than 3 months before donation 3. Any infection disease revealed during the screening 4. Latent period of infection disease according to the questionnaire 5. Gut disease 6. Longitudinal treatment with drugs 7. Any diet for 3 months before donation. 8. Obesity (BMI ≥ 30).