Modulation of gut microbiota through in vitro exposure to a traditional fermented food in the context of pathogen invasion

The gut microbiota consisting of bacteria, fungi, archea, and viruses and plays a role as a barrier against pathogen invasion to promote intestinal health and preventing organismal infections. This study examined the potential protective properties of Mabisi, a widely consumed traditional fermented dairy product in Zambia, against pathogen invasion in the gut. Using the in-vitro static INFOGEST model, we challenged the gut microbiota from a pooled stool sample pf six Zambian children) and previously exposed to Mabisi by adding model pathogens. We hypothesized that pathogen invasion is suppressed in in-vitro gut microbiota treated with Mabisi due to its ability to modulate the gut microbiota composition. Our microbiota challenge treatments were Mabisi, fructooligosaccharides (FOS) as a positive control, sterile water as a negative control, and with and without pathogens. Out of the two strains of pathogens added to the gut microbiota, Escherichia coli established in FOS treated gut microbiota, however not in Mabisi and sterile water treatments. Furthermore, we show that Mabisi modulated gut microbiota by increasing Pediococcus, a commensal bacteria and increased production of short chain fatty acids including acetate, propionate, lactate, isobutyrate, formate, and succinate in Mabisi treated gut microbiota compared to both FOS and sterile water treated gut microbiota. This study contributes to evidence of the beneficial role of fermented foods such as Mabisi through the prevention of pathogen invasion of the gut microbiota in children. ImportanceThis study provides evidence supporting the protective role of Mabisi, a traditional fermented dairy product, in preventing pathogen invasion in the gut microbiota of children. By using an in-vitro approach, we demonstrate that Mabisi treatment suppresses the establishment of Escherichia coli, a key pathogen, unlike fructooligosaccharides (FOS), a well-known prebiotic. Additionally, Mabisi modulates gut microbiota composition by increasing beneficial bacteria such as Pediococcus and enhancing short-chain fatty acid (SCFA) production, which is essential for gut health. These findings highlight the potential of traditional fermented foods as affordable, accessible dietary interventions for improving gut health and preventing infections, particularly in low-resource settings like Zambia.