Low Carriage Rates of Multidrug-Resistant Organisms in Prospective Stool Donors in a Large Fecal Microbiota Transplantation (FMT) Stool Bank

Abstract

Background: Fecal microbiota transplantation (FMT) has emerged as standard of care for Clostridioides difficile not responsive to antibiotic therapy. Rigorous screening of healthy donors is critical to patient safety. As part of routine donor evaluation for FMT, multidrug-resistant organism (MDRO) screening is performed to assess the presence of extended-spectrum β-lactamase–producing organisms (ESBLs), vancomycin-resistant enterococci (VRE), carbapenem-resistant Enterobacteriaceae (CRE), and methicillin-resistant Staphylococcus aureus (MRSA). Carriage rates of these organisms in a healthy, low-risk population are largely unknown. We report MDRO carriage rates among individuals screened for a stool donation program at a large-scale FMT stool bank. Methods: Individuals were screened at a nonprofit stool bank (OpenBiome, Cambridge, MA). Potential donors underwent in-person clinical assessment, including MDRO risk factors (eg, travel, occupation, healthcare exposure). If they met the clinical assessment criteria, laboratory testing, including MDROs, was performed. Once enrolled in the donor program, donors underwent repeated clinical and laboratory screening at 60-day intervals, with intermittent health checks throughout the donation period. Stool samples provided at 60-day intervals were screened for MDROs (ie, ESBL, CRE, VRE), and nasal swabs for MRSA were tested using culture-based methods. All stool samples tested for MDROs from prospective and enrolled donors were included. Results: Between February 2017 and July 2019, 247 individuals were screened for MDROs. Overall, 11 samples (0.04%) tested positive for ESBL, MRSA, or VRE. No CRE carriers were identified. Also, 2 individuals tested positive twice for ESBL, resulting in 13 of 1,688 (0.77%) positive screens. International travel in the previous 12 months was reported by 6 of 11 MDRO carriers. Occupations typically associated with MDROs were not observed in carriers. Most of the MDRO-positive donors were students; however, students make up the majority of the stool donor cohort. Conclusions: This study is the first to report background MDRO carriage rates in a population of otherwise healthy FMT stool donors. Although rare, MDROs were detected and should be part of standard guidelines for FMT donor screening. Most subjects testing positive for MDROs had defined risk factors associated with MDRO carriage, including international travel or exposure to healthcare environments. However, occupational exposure was not a factor associated with carriage in this study. Standardized donor screening guidelines for FMT are urgently needed to ensure that MDROs and risk factors for MDRO carriage are routinely screened for by all FMT providers. Stool banks present a unique public health opportunity to evaluate the background carriage rate of MDROs in healthy populations.

Funding: None

Disclosures: None