Mycobacterial Challenge and Bacterial Counting

Mice were exposed to an aerosol of Mtb H37Rv or BCG Pasteur strain to deposit a low dose of ∼100 CFU per lung by an inhalation exposure system (Glas-Col).64 The mycobacterial burden was determined by plating homogenates of spleen and lung onto Middlebrook 7H11 agar plates supplemented with 10% OADC and antibiotic mixture (40 U/mL polymyxin B, 4 μg/mL amphotericin, 50 μg/mL carbenicillin, and 2 μg/mL trimethoprim).