Gut microbiome dynamics and Enterobacterales infection in liver transplant recipients: A prospective observational study.

Background & Aims: The aim of this study was to investigate gut microbiome (GM) dynamics in relation to carbapenem-resistant Enterobacterales (CRE) colonization, CRE infection, and non-CRE infection development within 2 months after liver transplant (LT). Methods: A single-center, prospective study was performed in patients undergoing LT from November 2018 to January 2020. The GM was profiled through 16S rRNA amplicon sequencing of a rectal swab taken on the day of transplantation, and fecal samples were collected weekly until 1 month after LT. A subset of samples was subjected to shotgun metagenomics, including resistome dynamics. The primary endpoint was to explore changes in the GM in the following groups: (1) CRE carriers developing CRE infection (CRE_I); (2) CRE carriers not developing infection (CRE_UI); (3) non-CRE carriers developing microbial infection (INF); and (4) non-CRE carriers not developing infection (NEG). Results: Overall, 97 patients were enrolled, and 91 provided fecal samples. Of these, five, nine, 22, and 55 patients were classified as CRE_I, CRE_UI, INF, and NEG, respectively. CRE_I patients showed an immediate and sustained post-LT decrease in alpha diversity, with depletion of the GM structure and gradual over-representation of Conclusions: GM profiling before LT could improve patient stratification and risk prediction and guide early GM-based intervention strategies to reduce infectious complications and improve overall prognosis. Impact and implications: Little is known about the temporal dynamics of gut microbiome (GM) in liver transplant recipients associated with carbapenem-resistant Enterobacterales (CRE) colonization and infection. The GM structure and functionality of patients colonized with CRE and developing infection appeared to be distinct compared with CRE carriers without infection or patients with other microbial infection or no infection and CRE colonization. Higher proportions of antimicrobial-resistant pathogens and poor representation of bacteria and metabolic pathways capable of promoting overall host health were observed in CRE carriers who developed infection, even before liver transplant. Therefore, pretransplant GM profiling could improve patient stratification and risk prediction and guide early GM-based intervention strategies to reduce infectious complications and improve overall prognosis.