TABLE 1.
Summary of GAS transmission dynamics in infant mice
| Strain | Ratioa | Inoculum (CFU)b | No. of litters | No. of index mice | No. of contact mice | % transmissionc | Transmission comparison(s) (ratio-CFU)d |
|---|---|---|---|---|---|---|---|
| emm3 | 1:1 | 104 | 3 | 20 | 20 | 0 | |
| 106 | 3 | 20 | 20 | 0 | |||
| 107 | 3 | 22 | 21 | 19.1 | 1:1-104, 106* | ||
| 1:2 | 104 | 3 | 13 | 28 | 0 | ||
| 106 | 3 | 12 | 23 | 47.8 | 1:1-106*** | ||
| 1:2-104# | |||||||
| 107 | 3 | 11 | 22 | 90.9 | 1:1-107# | ||
| 1:2-106** | |||||||
| emm3ΔhasA | 1:1 | 107 | 3 | 12 | 14 | 0 | emm3, 1:1-107 (P = 0.07) |
| emm87 | 1:1 | 104 | 2 | 11 | 11 | 27.3 | emm3, 1:1-104* |
| 107 | 2 | 12 | 13 | 53.8 | emm3, 1:1-107 (P = 0.13) | ||
| 1:2 | 104 | 2 | 9 | 16 | 0 | ||
| 107 | 3 | 10 | 18 | 38.9 | emm3, 1:2-107*** | ||
| emm87(hasAemm3) | 1:1 | 107 | 2 | 13 | 14 | 14.3 | emm87, 1:1-107* |
| emm87(hasAemm3-ΔcovS) | 1:1 | 107 | 3 | 18 | 18 | 5.6 | emm87, 1:1-107** |
| emm87ΔcovS | 1:1 | 107 | 2 | 13 | 14 | 0 | emm87, 1:1-107** |
a
Index-to-contact ratio of infant mice in litters.
b
CFU administered to index mice.
c
Transmission rate expressed as a percentage of contact mice with a detectable intranasal burden of the corresponding GAS strain.
d
Comparison of transmission rates using Fisher’s exact test (two tailed) (*, P < 0.05; **, P < 0.01; ***, P < 0.001; #, P < 0.0001).