Figure 2. Increased bacterial burdens and lung damage after A. baumannii infection in aged mice. Young and aged mice were infected intratracheally with 5×106 CFU of LAC-4 and the lung, blood, and spleen were collected at 0 h and 24 hpi. (A) Bacterial burdens in the lung, blood, and spleen of young and aged mice at 24 hpi were counted on TSA plates. (B) Lung histopathology of young and aged mice were observed at 0 h and 24 hpi (magnification=200×). (C) Serum albumin levels in BALF of young and aged mice were determined by ELISA. Data are presented as mean ± SEM of five mice per condition and represent one of 2 independent experiments. Statistical analyses were performed by Student’s t test. *, P < 0.05, **, P < 0.01.