Necrotizing pneumonia: This is a rare complication of bacterial pneumonia (lung infection by bacteria) in which tissue death (necrosis) begins to occur in the lung. Necrosis is the word for cellular or tissue death due to lack of oxygen. In necrotizing pneumonia, there is a reduction in the vascular supply to the lungs, leading to areas of cellular death. The lack of blood supply due to damaged blood vessels impairs the delivery of antibiotics to the infection, allowing for further progression of the infection.
Chatha, Neela, Dalilah Fortin, and Karen J. Bosma. "Management of necrotizing pneumonia and pulmonary gangrene: A case series and review of the literature." Can Respir J 21.4 Jul-Aug 2014: 239-245.