3D Hydrodynamic Model for Heterogeneous Biofilms with Antimicrobial Persistence.

摘要

Biofilms are known to be more persistent to antimicrobial treatment than planktonic bacterial cells. In addition to the protective extracellular matrix formed primarily by expopolysaccharides (EPS) one of the current point of views on this issue is that there may exist a small portion of phenotypic bacterial variants, known as persisters, which are invulnerable to antimicrobial agents, while the majority of the bacterial cells is susceptible to antimicrobial agents. In this paper, a 3D hydrodynamic model for spatially heterogeneous biofilms based on the phase field formulation is proposed and applied to analyze the mechanism of antimicrobial persistence of biofilms by acknowledging the existence of persisters and susceptible cells in the total population of bacteria. A numerical scheme is devised to solve the model consisting of partial differential equations, which is implemented on graphic processing units (GPUs) for high performance computing, in 3-D space and time. Antimicrobial treatment in an infinitely long quiescent water channel and in a short water tube under inflow and outflow boundary conditions are simulated using the new model, in which multiple dosing locations and strategies are investigated. The model demonstrates the internal spatial and temporal distribution of bacteria, EPS, nutrient and antimicrobial agents, providing a useful tool for analyzing the mechanism of biofilm persistence to antimicrobial agents in an aqueous environment. The numerical result also confirms that the periodic dosing strategy is more effective than the constant dosing strategy in disinfecting biofioms.