FIG. 5.

Analysis of organ weight and enumeration of bacterial loads in tissue and blood after induction of tularemia. Following intranasal infection, mice (n = 3 to 6) were sacrificed at different time intervals. Lungs and spleens were dissected, weighed, and homogenized, and samples were serially diluted to determine LVS CFU by culture. The data are reported as weight per milligram and CFU per milligram of either spleen (A and C) or lung (B and D) tissue over time, and the error bars represent standard deviations (SD). (E) In a separate experiment, bacterial loads were also evaluated in blood from all mice (n = 25) collected at different time intervals (24 to 96 h). Also shown are CFU values detected in the blood of ∼75% of the mice that became moribund at day 7 (n = 18) and the ∼25% of survivor mice at days 7, 15, and 50 (n = 7). The data are expressed as CFU per milliliter, and the error bars represent SD. Differences in organ weight (mg) were either significant (*, P < 0.05) or highly significant (**, P < 0.01) in comparison to uninfected controls. “Survivor” data in panels A and B include organ weights determined at days 7, 15, and 50 postinfection (no differences were observed between the time points).