Fig. 3.
Kidney and bladder bacterial burden. A: mean bladder colony-forming unit (CFU) counts at 24 h afte uropathogenic Escherichia coli (UPEC) inoculation were significantly higher at 1.38 × 107 ± 1.35 × 107 in Car2−/− mice versus 2.83 × 106 ± 3.66 × 106 in Car2+/+ mice (P = 0.006). However, at 48 h after UPEC inoculation, bladder CFUs were similar between Car2+/+ and Car2−/− mice at 2.04 × 107 ± 2.55 × 107 versus 1.68 × 107 ± 1.25 × 107 (P = 0.745). B: mean kidney 24 h postinoculation CFUs were higher in Car2−/− mice compared with Car2+/+ mice at 301,357 ± 749,330 and 19,987 ± 53,965, respectively (P = 0.04). Mean CFUs were also higher at 48 h in Car2−/− mice compared with Car2+/+ mice at 959,488 ± 2.96 × 106 versus 101,357 ± 197,686, respectively. These 48-h kidney CFU changes did not reach statistical significance secondary to a smaller n value and larger SD (P = 0.26). Bacterial clearance from the kidney was evaluated at 24 and 48 h. Kidney clearance of bacteria was achieved in 47% of Car2+/+ kidneys versus 19% of Car2−/− kidneys at 24 h and 50% of Car2+/+ kidneys versus 6% of Car2−/− kidneys at 48 h. Both 24- and 48-h kidney bacterial clearance differences between genotypes were significant, with P values of 0.032 and 0.012, respectively. n = 32 kidneys/genotype at 24 h and 14 kidneys for Car2+/+ genotype along with 16 kidneys for the Car2−/− genotype.