FIG 1.

MGAS2221 is effectively cleared from pulmonary infections but not from subcutaneous infections of C57BL/6J mice. In total, 1.2 × 10⁸ and 0.8 × 10⁸ CFU of MGAS2221 were inoculated into mice intratracheally (I.T.) and subcutaneously (Subcut), respectively. (A) GAS loads in the lung or in skin infection sites at 1 h and 24 h after inoculation. (B and D) Representative Gram stain images of lung sections at 30 min (×20 magnification) (B) and 24 h (×4 magnification) (D) after inoculation. AD and BT, alveolar duct and bronchial terminus, respectively. Panel B shows GAS bacteria as blue spots at bronchial termini and along alveolar ducts, while panel D shows the absence of stained GAS bacteria. (C) Representative H&E-stained image of a lung section at 24 h after inoculation. The arrowheads indicate the clumps of recruited neutrophils at the bronchial termini or along alveolar ducts.