LW/BW ratio and bacterial counts in organs and blood.

Lungs, spleen, and kidneys were removed aseptically from euthanized animals, weighed, and immediately processed. The right lung, spleen, and kidneys were cut into <0.5-cm pieces, and 0.2- to 0.3-g samples were homogenized in 0.9% saline, followed by quantification of CFU by serial dilutions on 5% sheep blood agar (Remel). Arterial blood collected every 2 to 4 h for biomarker analysis (see above) was diluted (100 μl of blood in 900 μl of sterile water) and plated for quantitative culture on 5% sheep blood agar (Remel).