Experimental modeling of pediatric intestinal dysbiosis using an artificial gastrointestinal tract bioreactor system

BACKGROUND: Traditional microbial culture methods cannot replicate the complex intermicrobial interactions characteristic of the intestinal microbiota in vivo. Therefore, the development and use of modern bioreactor systems for experimental modeling of pediatric intestinal dysbiosis are relevant, as they ensure standardized experimental conditions and reproducibility of results without ethical limitations.

AIM: The study aimed to develop and validate a method for experimental modeling of pediatric intestinal dysbiosis using an artificial gastrointestinal tract bioreactor system to study the pathogenic mechanisms of microbiota imbalance and assess the efficacy of corrective interventions.

METHODS: The study was performed using an automated gastrointestinal tract modeling system consisting of three reactors (stomach, duodenum, colon) with controlled temperature, pH, and anaerobic conditions. A stool sample from a six-year-old donor was used. The observation period was 35 days following fecal suspension inoculation into the reactors. Validation criteria included the correspondence between the microbial profile of the artificial microbiota and the clinical profile of the initial sample, and stability of the microbial consortium by key taxa. Evaluation methods included bacteriological culture on selective media and quantitative polymerase chain reaction using the Kolonoflor-16 panel. A coefficient of variation ≤20% for major bacterial populations was established as the stability criterion.

RESULTS: Polymerase chain reaction and bacteriological testing of the initial stool sample revealed a critical deficiency of obligate microbiota (reduced lactobacilli and bifidobacteria) and excessive growth of opportunistic microorganisms, consistent with grade III dysbiosis. The developed bioreactor model successfully reproduced dysbiotic alterations. The total bacterial mass in the colon reactor was 13.21 ± 0.20 log DNA copies/mL on day 8 and 13.38 ± 0.09 log DNA copies/mL on day 35 with baseline 13.30 log DNA copies/mL. The model reproduced the key characteristics of pediatric dysbiosis, including obligate microbiota deficiency (Lactobacillus spp., Bifidobacterium spp.) and overgrowth of opportunistic microorganisms (E. coli, C. perfringens, Enterobacter spp., etc.). Stability analysis demonstrated coefficients of variation <20% for all key bacterial populations starting from week 2 of cultivation. The model ensured stable reproduction of grade III intestinal dysbiosis throughout the 35-day observation period.

CONCLUSION: A method for experimental modeling of pediatric intestinal dysbiosis using an artificial gastrointestinal tract system has been successfully developed and validated. This model provides new opportunities for in-depth study of pathogenetic mechanisms of microbiota disturbances in childhood, as well as for screening and evaluating the efficacy of probiotics, prebiotics, and other corrective interventions under conditions approximating physiological ones.