Strain | Relevant phenotype | Expt | Geometric mean CFU^{a} per well after Henle 407 cell lysis (SD) | |
---|---|---|---|---|

0 h | 4 h | |||

Ty2 | Wild type; regulated Vi expression | 1 | 6.86 × 10^{4} (1.42) b | 5.03 × 10^{5} (2.05) c |

2 | 4.68 × 10^{5} (1.02) d | 2.54 × 10^{6} (1.66) e | ||

CVD 908-htrA
| Vaccine strain; regulated Vi expression | 1 | 5.43 × 10^{3} (1.04) f | 1.30 × 10^{4} (1.41) g |

2 | 9.03 × 10^{3} (2.27) h | 3.00 × 10^{4} (1.04) i | ||

CVD 909 | Vaccine strain; constitutive Vi expression | 1 | 7.52 × 10^{2} (1.08) j | 1.05 × 10^{3} (1.39) k |

2 | 8.72 × 10^{2} (1.70) l | 1.08 × 10^{3} (1.26) m |

↵a Geometric mean of duplicate wells. Comparisons by Student's

*t*test: b versus f, P = 0.06; f versus j, P = 0.005; d versus h, P = 0.092; h versus l, P = 0.095; c versus g, P = 0.049; g versus k, P = 0.017; e versus i, P = 0.048; and i versus m, P = 0.026. Overall probability using Fisher's test of combined probabilities: Ty2 versus CVD 908-*htrA*, P = 0.034 and*P*= 0.017 at 0 and 4 h, respectively; CVD 908-*htrA*versus CVD 909, P = 0.004 and P = 0.004 at 0 and 4 h, respectively.