A SIMULATION OF MICROBIAL COMPETITION IN THE HUMAN COLONIC ECOSYSTEM

Many investigations of the interactions of microbial competitors in th e gastrointestinal tract used continuous-flow anaerobic cultures, The simulation reported here was a deterministic 11-compartment model code d by using the C programming language and based on parameters from pub lished in vitro studies and assumptions where data were unavailable, T he resource compartments were glucose, lactose and sucrose, starch, so rbose, and serine, Six microbial competitors included indigenous nonpa thogenic colonizers of the human gastrointestinal tract (Escherichia c oli, Enterobacter aerogenes, Bacteroides ovatus, Fusobacterium varium, and Enterococcus faecalis) and the potential human enteropathogen Sal monella typhimurium. Flows of carbon from the resources to the microbe s were modified by resource and space controls, Partitioning of resour ces to the competitors that could utilize them was calculated at each iteration on the basis of availability of all resources by feeding pre ference functions, Resources did not accumulate during iterations of t he model, The results of the computer simulation of microbial competit ion reproduced published experimental results, Graphical output of sim ulations was presented for the base case competition model and for var ious modifications of the model, The results were based on few measure d parameters but may be useful in the design of user-friendly software to aid researchers in defining and manipulating the microbial ecology of colonic ecosystems as relates to food-borne disease.