Long-term continuous cultivation of Kenyan infant fecal microbiota using the host adapted PolyFermS model

Appropriate in vitro models to investigate the impact of novel nutritional strategies on the gut microbiota of infants living in rural Africa are scarce. Here, we aimed to develop such a continuous gut fermentation model based on the PolyFermS platform. Eight immobilized Kenyan infant fecal microbiota were used as inoculum for continuous PolyFermS colon models fed with medium mimicking the weaning infant diet. Fructo-oligosaccharides (FOS) supplementation (1, 4 and 8 g/L) and cultivation pH (5.8 and 6.3) were stepwise investigated. Conditions providing a close match between fecal and in vitro microbiota (pH 5.8 with 1 g/L FOS) were selected for investigating long-term stability of four Kenyan infant PolyFermS microbiota. The shared fraction of top bacterial genera between fecal and in vitro microbiota was high (74-89%) and stable during 107 days of continuous cultivation. Community diversity was maintained, and two distinct fermentation metabolite profiles, propiogenic and butyrogenic, of infant fecal microbiota established from day 8 onwards and stayed stable. We present here the first rationally designed and accurate continuous cultivation model of African infant gut microbiota. This model will be important to assess the effect of dietary or environmental factors on the gut microbiota of African infants with high enteropathogen exposure.