Which condition refers to tissue decay due to bacterial invasion?

Gangrene refers to tissue decay caused by the presence and activity of bacteria, leading to the death of body tissue. It is typically associated with a loss of blood supply, which can result from various factors, including infection, trauma, or chronic health conditions. As bacteria invade and proliferate in the affected tissue, they produce toxins that can exacerbate the decay, leading to more extensive damage.

While first-degree and second-degree burns are injuries to the skin caused by heat, chemicals, or radiation, they do not directly involve bacterial invasion leading to decay. Pressure sores, also known as bedsores or decubitus ulcers, are localized areas of tissue damage that can result from prolonged pressure in combination with shear and friction, but they do not specifically denote decay due to bacterial infection. In contrast, gangrene encapsulates the concept of bacterial invasion leading to significant tissue damage and necrosis, making it the most fitting choice for this question.