Figure 1. Clinical disease course after an intracerebral infection with E. coli K1 (10⁵ CFU/ml) in young and aged mice.

(A) Mortality following intracerebral E. coli K1 infection was significantly higher in aged mice (73%) than in young mice (47%; **p = 0.0025, log-rank test). (B) Deceased aged mice showed a significantly higher clinical score than deceased young mice 24 hours p.i. (*p = 0.02), 48 hours p.i. (**p = 0.008), and 72 hours p.i. (**p = 0.002; Mann-Whitney U-test followed by Bonferroni correction) indicating a faster development of clinical symptoms. Data are shown as medians (25./75. percentile). (C) Weight loss 48 hours p.i. was more pronounced in aged mice than in young mice (4.7 ± 2.5 g versus 2.8 ± 2.2 g, *p = 0.02; Student's t-test). After the acute phase of the infection, young mice rapidly gained weight again, whereas aged mice did not recover weight. Data are shown as means ± SD.