Determination of the bacterial load in lung tissue

To determine the bacterial load in the lung tissue, the lung tissues of mice were homogenized and diluted with sterile saline (1:10⁴, 10⁵, 10⁶). Diluted lung tissue homogenate (100 µL) was inoculated into LB agar plates and incubated overnight at 37 °C. The bacterial load in the lung tissue was determined by counting the number of bacteria on the LB agar plates at different concentrations (colony-forming unit/g).