Liver transplantation (LT) is a single option for treatment end-stage of liver diseases. Although repeated antibiotic therapy can cause major changes in the intestinal microbiota. There is growing evidence regarding the role of gut microbiota in the before and after operative course and their impact on patient outcomes in LT. It plays a crucial role in controlling the process of digestion because gut microbiota produce, extract, and absorb a wide range of metabolites, such as lipids, vitamins, bile acids, short chain fatty acids, and amino acids. Additionally, gut microbiota have the ability to directly stop the colonization of foreign bacteria by impeding their growth by appropriating available resources and/or producing antibacterial molecules. This study was conducted on 31 liver transplant patients in Gastroenterology Surgical Center (GEC), Mansoura University, Egypt. We collected 87 stool samples for the current study, dividing them into 3 groups, before LT, after one week from LT and two weeks from LT. Isolated bacteria from patient before LT including Phylum: Bacteroidota (38.1%), phylum: Firmicutes (58.75%) and Phylum: Proteobacteria (3.17%). Isolated bacteria from patients after one week of LT including Phylum: Bacteroidota (38.1%), Phylum: Firmicutes (58.7%) and Phylum: Proteobacteria (39.0%). Isolated bacteria from patients after two weeks LT including Phylum: Bacteroidota (21.43%), Phylum: Firmicutes (58.7%) and Phylum: Proteobacteria (35.7%).

Keywords: Liver transplantation, Microbiota, Bacteroidota, Firmicutes, Proteobacteria.