Team:British Columbia/modeling results

The Binary Outcome

Biofilm Death

Figure 1: The simulated behavior of the biofilm and phage populations over 1200 mins (20 hrs). The percent of the total biofilm poopulation remaining after phage introduction (blue) sharply declines at 400 min. This coincides with the sharp increase of the percent of the biofilm population infected by phage (green). The phage population (here, represented by the P-factor) peaks shortly after 400 mins. These features suggest that the accumulation of phage particles in the biofilm between 0 and 400 min triggers mass host cell lysis leading to the destruction of the biofilm by 900 min (15 hrs).

Figure 2: The dynamics of the extracellular concentrations of AIP (purple) and DspB (red) over 1200 mins (20 hrs). The maximum level of AIP concentration and the activation threshold level are indicated by the upper and lower dashed lines, respectively. AIP concentration is shown to steadily decrease over time, but does not fall below the threshold level during the 1200 mins. DspB concentration rises rapidly at 400 min, coinciding with decrease in biofilm population and increase in phage population (indicated in Figure 1), and then peaks at 600 min when the biofilm population is substantially reduced.

Survival

Sensitivity Analyses

Phage virulence is critical to successful biofilm dispersal

Half-life is not a main outcome-determining factor

DspB Makes Life Easier For the Phage

Discussion

Although our model was initially developed to simulate the behavior of our genetically engineered (GE) system, it can be applied to predict the dynamics of other biofilm systems that are introduced to a biofilm matrix-degrading phage. By setting the model parameters to values that represent the properties of a real-world biofilm system, we can simulate scenarios where the biofilms are exposed to a GE phage functionally similar to ours. We can also incorporate information on the properties of the phage by modifying certain parameters. Below, we present results for simulations of medically relevant biofilm scenarios where GE phage may be considered for the therapeutic solution.