Table 2.
Persistence of vaccine strainsa.
| Vaccine strain | Initial culture conc. | Inoculum/mouse | Persistence as measured by kan- or hyg-resistant CFUs | ||
|---|---|---|---|---|---|
| CFUs at 6-weeksb | CFUs at 12-weeksb | CFUs at 18-weeksb | |||
| PBS (liver) | 0 | 0 | 0 | 2760 | 1120 |
| PBS (spleen) | 0 | 0 | 0 | 3380 | 2570 |
| MAP K-10 (liver) | 1.47 × 106 | 1.47 × 105 | 0 | NDc | ND |
| MAP K-10 (spleen) | 3 | ND | ND | ||
| Strain 315 (liver) | 2.8 × 104 | 2.8 × 103 | 0 | 0 | 0 |
| Strain 315 (spleen) | 0 | 32 | 0 | ||
| Strain 316 (liver) | 1.8 × 105 | 1.8 × 104 | 0 | 0 | 0 |
| Strain 316 (spleen) | 0 | 8 | 0 | ||
| Strain 317 (liver) | 1.26 × 106 | 1.26 × 105 | 0 | 0 | 0 |
| Strain 317 (spleen) | 0 | 104 | 0 | ||
| Strain 318 (liver) | 4.2 × 105 | 4.2 × 104 | 0 | 0 | 0 |
| Strain 318 (spleen) | 0 | 0 | 0 | ||
| Strain 319 (liver) | 2.1 × 105 | 2.1 × 104 | 0 | 20 | 0 |
| Strain 319 (spleen) | 0 | 0 | 0 | ||
| Strain 320 (liver) | 4.2 × 106 | 4.2 × 105 | 554 | 420 | 34 |
| Strain 320 (spleen) | 2180 | 1410 | 0 | ||
| Strain 321 (liver) | 2.95 × 106 | 2.95 × 105 | 738 | 20 | 12 |
| Strain 321 (spleen) | 1550 | 2860 | 0 | ||
| Strain 329 (liver) | 2.14 × 106 | 2.14 × 105 | 476 | 580 | 2 |
| Strain 329 (spleen) | 206 | 712 | 0 | ||
a
All values are reported as average CFU/ml among five mice.
b
All values represent kan- or hyg-resistant colonies except for the PBS control where the K-10 challenge was plated on non-selective media.
c
ND, not determined. Because K-10 challenge dose could not be distinguished from K-10 vaccination dose, these values could not be obtained.