Table 1 Stochastic version of the model

From: The effect of stochastic noise on antibiotic resistance in intestinal flora

No.

Reaction

Propensity function

State change vector

1

X

\({w}_{1}={r}_{p}(1-({k}_{1}\frac{X}{\Omega }+{k}_{2}\frac{Y}{\Omega }))X\)

(1,0,0)

2

X → :Z

\({w}_{2}={k}_{{PB}}\frac{{Z}^{2}}{{Z}^{2}+{a}^{2}{\Omega }^{2}}X\)

(−1,0,0)

3

X → 

\({w}_{3}={d}_{p}X\)

(−1,0,0)

4

X → 

\({w}_{4}={\eta }_{1}X\)

(−1,0,0)

5

Y

\({w}_{5}={r}_{p}(1-({k}_{1}\frac{X}{\Omega }+{k}_{2}\frac{Y}{\Omega }))Y\)

(0,1,0)

6

Y → :Z

\({w}_{6}={k}_{{PB}}\frac{{Z}^{2}}{{Z}^{2}+{a}^{2}{\Omega }^{2}}Y\)

(0,−1,0)

7

Y → 

\({w}_{7}={d}_{p}Y\)

(0,−1,0)

8

Y → 

\({w}_{8}={\eta }_{2}Y\)

(0,−1,0)

9

Z

\({w}_{9}={r}_{B}(1-\frac{Z}{\Omega })Z\)

(0,0,1)

10

Z → :X,Y

\({w}_{10}={k}_{{BP}}\frac{{({k}_{1}X+{k}_{2}Y)}^{2}}{{({k}_{1}X+{k}_{2}Y)}^{2}+{b}^{2}{\Omega }^{2}}Z\)

(0,0,−1)

11

Z → 

\({w}_{11}={d}_{p}Z\)

(0,0,−1)

12

Z → 

\({w}_{12}={\eta }_{1}Z\)

(0,0,−1)

  1. There were 12 reaction steps, each corresponding to a propensity function wj(j = 1, 2, …, 12) that depended on the dynamic parameters used in the deterministic equations and the bacterial population size. Parameter Ω, which had the unit of volume, controls the total population of microorganisms in the system and is often referred to as the system size.