Table 1.
Estimates from bootstrap analysis of in vivo mathematical model.
| Day | Standard plating CFU ml−1a |
Plasmid frequency % |
Per day (95% confidence interval) |
Generation timec h |
Cumulative bacteria CFU ml−1 (95% confidence interval)b |
|
|---|---|---|---|---|---|---|
| r | δd | |||||
| 1 | 3.78 × 102 | 66.68 | 3.78 × 102 (3.03 × 102 – 4.20 × 102) | |||
| 13 | 3.03 × 104 | 12.46 | 0.78 (0.68 – 0.88) | 0.41 (0.33 – 0.51) | 21.42 | 6.39 × 104 (3.18 × 104 – 1.04 × 105) |
| 26 | 6.31 ×105 | 6.06 | 0.31 (0.19 – 0.41) | 0.07 ( 0.05 – 0.18) | 54.04 | 8.56 × 105 (5.79 × 105 – 1.12 × 106) |
| 69 | 8.55 × 105 | 2.33 | 0.12 (0.07 – 0.18) | 0.12 (0.06 – 0.18) | 134.51 | 4.78 × 106 (2.79 × 106 – 7.01 × 106) |
| 111 | 1.31 × 106 | 0.61 | 0.18 (0.12 – 0.24) | 0.17 (0.11 – 0.22) | 94.36 | 1.27 × 107 (1.08 × 107 – 1.45 × 107) |
| 77 | 5.95 ×× 106 | 1.05 | 0.55 (0.27 – 0.83) | 0.31 (0.04 – 0.56) | 30.10 | 1.64 × 107 (1.16 × 107 – 2.15 × 107) |
Day 77 data represent mice treated with dexamethasone for 8 d.
a
Mean of five mice per time point.
b
Calculations made with s = 0.18.
c
Generation time = ln(2) / r; hence, if r = 1, doubling time = 16.6 h; if r = 0.1, doubling time = 166 h.
d
Variation in the death rate is reflected in the cumulative bacterial burden. For the extreme case that δ= 1, the cumulative burden at day 111 would be 7.76 × 106 CFU ml−1; if δ= 0, the cumulative burden would be the same as that determined by standard plating.