What is a common sign of a bacterial infection?

Pus is a common sign of a bacterial infection because it is a direct result of the body's immune response to fight off bacteria. When a bacterial infection occurs, the immune system sends white blood cells to the site of infection. These white blood cells help to combat the bacteria, and as they accumulate and die, they can form pus – a thick fluid that often contains dead cells, bacteria, and tissue debris. The presence of pus typically indicates that the infection is localized, and it can often be seen in conditions such as abscesses, wounds, or certain skin infections. This makes pus a strong indicator of a bacterial infection when compared to other signs, which may be related to different types of infections or health issues.