Autopsy of the body of a 43-year-old man, who died of heart and lung failure, detected a cavity 3 cm in diameter in his lower right pulmonary lobe. The cavity is filled with green-gray contents. Histology revealed that the wall of this formation is made up of connective tissue and juvenile granulation tissue; the lumen contains neutrophilic leukocytes and their decay products. What type of inflammation is it?