Spatiotemporal Population Dynamics of Genetically Modified and Native Gut Bacteria for CRC Detection

Because colorectal cancer (CRC) is a major contributor to cancer mortality, early detection is critical. Genetically modified E. coli could serve as living sensors for CRC, but to be effective these engineered bacteria must survive, engraft and proliferate in the gut. We model the spatiotemporal population dynamics of native and engineered native bacteria (ENB) using generalized Lotka–Volterra equations coupled to diffusion and advection. By varying initial concentrations, growth rates, and interaction types and strengths, we obtain phase diagrams delineating coexistence, dominance, and disappearance of the ENBs. Numerical simulations in one and two dimensions show how mutualism, competition, commensalism and predator–prey interactions govern spatial patterns and stability. Our results identify parameter regimes where engineered bacteria can persist within the native microbiome, providing insights for synthetic sensors of CRC.