TABLE 2

ID50 determination for strains in urogenital tract infections

Strain and methodNo. of positive mice (n = 10) inoculated with dose (IFU) ofa:ID50 (IFU)b
103104105106
L2P
    Culture1237316,227
    Seroconversion2479251,116
L2P.pGFP::SW2
    Culture5910101,000
    Seroconversion791010<1,000
L2P.pCDS5KO
    Culture125926,827
    Seroconversion345721,258
  • a For culture, data are numbers of mice that were culture positive at any time point postinfection. Culture detection of infection was attempted on swabs collected at 4, 7, 10, 14, and 21 days postinfection (Fig. 1). For seroconversion, data are numbers of mice displaying seroconversion for plasma IgG antibody (day 35 postinfection; positive seroconversion was empirically set at a titer of 20).

  • b Calculated dose that will achieve a 50% infection rate. Data were calculated by the method of Reed and Muench (36).