What infection can lead to severe tissue death if not treated promptly?

Cellulitis is a bacterial skin infection that spreads rapidly through the layers of skin and surrounding tissue. If not treated promptly, it can lead to severe complications, including tissue death, also known as necrosis. This is particularly concerning in cases where the infection progresses due to delayed treatment, as the bacteria can multiply and produce toxins that damage the tissue, leading to serious conditions such as sepsis.

The other infections listed do not typically result in severe tissue death if left untreated. Pneumonia primarily affects the lungs; urethritis is an infection of the urethra; and bronchitis involves inflammation of the bronchial tubes. While these conditions can lead to other significant health problems, they do not have the same immediate risk of causing extensive tissue necrosis as cellulitis does.