The skin provides a remarkably good barrier against bacterial infections. Although many bacteria live on the skin, they're normally unable to establish an infection. Bacterial skin infections may affect a single spot, appearing as a pimple, or may spread within hours, affecting a large area. Skin infections can range in seriousness from minor acne to a life-threatening condition, such as staphylococcal scalded skin syndrome.
Many types of bacteria can infect the skin.
The most common are Staphylococcus and Streptococcus. Infections from less common bacteria may develop in hospitals or nursing homes or while gardening or swimming in a pond, lake, or ocean. Skin damaged by sunburn, scratching, or other irritation also is more likely to get infected. In fact, any break in the skin predisposes a person to infection. For the most part, keeping the skin undamaged and clean prevents infections.