TABLE 2.
LD50s for Y. pestis strains in mouse models of pneumonic and bubonic plague
| Model | Strain or mutation | LD50 (mean ± SD)a |
|---|---|---|
| Pneumonic plague | Wild type | 329 ± 105 |
| Δpsn2045.1 or psn::kan2045.6 | 1.1 × 104 ± 2.9 × 103 | |
| Δirp2-2046.3 or irp2::kan2046.1 | 2.6 × 105 ± 1.8 × 105 | |
| Δpgmb | >3.9 × 106 | |
| Bubonic plague | Wild type | 25 ± 12 |
| Δpsn2045.1 or psn::kan2045.6 | >2.6 × 107 | |
| Δirp2-2046.3 or irp2::kan2046.1 | >1.3 × 107 |
a
> indicates an LD50 above the highest bacterial doses tested from at least two independent experiments. Values were calculated from two or more independent trials. Probit analysis using SPSS determined that the intranasal LD50s of the three mutants are significantly different from each other (see text). For statistical analysis, the Δpgm LD50 was set at 3.9 × 106.
b
Two Δpgm strains [KIM5 and KIM5(pCD1Ap) (Table 1)] with a native and recombinant pCD1 were tested but showed the same loss of virulence.