TABLE 1

Virulence of Y. pestis strains expressing subsets of type III secretion effector proteinsa

Strain% lethality (no. of mice killed/total no. of mice infected)Median time to death (days)Significance against KIM1001 (P value)
KIM1001ΔT3SE0 (0/8)NA<0.0001
KIM1001ΔT3SE::+yopHE0 (0/10)NA<0.0001
KIM1001ΔT3SE::+yopHEM0 (0/6)NA<0.0001
KIM1001ΔT3SE::+yopHEK0 (0/6)NA<0.0001
KIM1001ΔT3SE::+yopHEKM53 (9/17)9<0.0001
KIM1001ΔT3SE::+yopHEKMA88 (14/16)60.1305
KIM1001ΔT3SE::+yopHEKMT87 (13/15)60.1184
KIM1001ΔT3SE::+yopHEKMJ85 (22/26)5.50.1031
KIM1001ΔT3SE::+yopHEKMJT100 (5/5)70.1501
KIM1001ΔT3SE::+yopHEKMAJ100 (5/5)70.4756
KIM1001ΔT3SE::+yopHEKMAT80 (4/5)70.1206
KIM1001ΔT3SE::+yopHEKMAJT100 (15/15)50.3890
KIM1001100 (12/12)4.5NA
  • a All infection experiments were performed with a subcutaneous dose of 1 × 103 CFU in C57BL/6 mice. Median time to death references only those mice within each group that succumbed to infection; any mice that survived for the duration of the experiment were excluded from the calculation of this metric. Significance was calculated for each curve compared to the KIM1001 curve by the Mantel-Cox test. NA, not applicable.