Table I.

Average scores for histopathological lesions. In these cases, vasculitis is regarded as transmural inflammation, while interstitial edema refers to perivascular and peribronchial edema

	E. coli	P. aeruginosa
Extent of interstitial edema	1.1	1.3
Extent of alveolar edema	1.9	0.9
Amount of fibrin	1.6	1.6
Number of interstitial leukocytes	1.3	1.2
Number of alveolar leukocytes	1.5	1.9
Extent of necrosis	1.5	1.4
Number of erythrocytes in alveoli	1.6	2.3
Vasculitis	0.3	0.6
Thrombosis	0.1	0.3
Epithelial cell loss in conductive airways	1.6	1.9
Lymphoid cuffing	0.6	0.2

The severity of lesions was graded as 0 — no lesions (0%), 1 — mild lesions (0% to 33% of tissue) or a few cells, 2 — moderate lesions (34% to 66% of tissue) or a moderate number of cells, and 3 — massive/severe lesions (> 66% of tissue) or a massive number of cells.