Author(s): Vedor, Rita ; Barbosa, Joana C. ; Machado, Daniela ; Carvalho, Nélson Mota de ; Costa, Célia Maria ; Madureira, Ana Raquel ; Gomes, Ana M.
Date: 2025
Persistent ID: http://hdl.handle.net/10400.14/55789
Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Introduction: Gut microbiota are the collection of bacteria, archaea and eukarya that colonise the gastrointestinal tract of animals and humans [1]. Prebiotics, probiotics and postbiotics have a positive e=ect on improving intestinal homeostasis by modulating both the microbiota profile and metabolic functions. This modulation may lead to beneficial changes in the production of specific organic acids and the consumption of extracellular ammonia. [2]. To study the e=ects of macro- or micronutrients, bioactive compounds and/or pre- or probiotics on the gut microbiota, in vitro digestion and colonic fermentation models have been developed. These models are a powerful tool to determine the e=ect of prebiotics or probiotics on the microbiota profile and/or the e=ect of these on metabolite production [4]. Objectives: The main goal of the study was to evaluate the influence of a pre-digested encapsulated next- generation probiotic, Akkermansia muciniphila, on gut microbiota during dysbiosis, caused by the oro-gastrointestinal pathogen Escherichia coli O157:H8. The specific aim is to determine whether the encapsulated probiotic has a therapeutic e=ect or primarily acts as a preventive measure. The analysis is focused on ammonia and short chain fatty acids (SCFAs) to understand the e=ect of the encapsulated A. muciniphila on gut microbiota metabolism. Furthermore, this work focused on evaluating the modulation of the gut microbiota in terms of microbial diversity. Conclusions: The incorporation of A. muciniphila, encapsulated in a calcium-alginate matrix, led to the modulation of both healthy and E. coli O157:H7-infected microbiota. This modulation resulted in an increase in the microbial diversity of the gut microbiota, a decrease in extracellular ammonia, and an increase in the production of SCFA, particularly acetate and propionate. In relation to total nitrogen ammonia, the results indicate that A. muciniphila takes in ammonia intracellularly, leading to a decrease in levels after 48 hours of faecal fermentation. The supplementation with calcium- alginate capsules containing A. muciniphila resulted in the modulation of microbiota diversity and metabolism, leading to increased levels of propionate and acetate, while butyrate was absent. This study found an increase in beneficial microbial genera, including Morganella, Bifidobacterium, and Bacteroidetes, indicating the restoration of gut microbiota homeostasis after a state of dysbiosis caused by infection with E. coli O157:H7.
