Which type of bacterial infection commonly occurs on the skin?

Staphylococcus aureus is a type of bacteria that is commonly found on the skin and can lead to infections, particularly when it breaches the skin barrier through cuts, abrasions, or other forms of damage. This bacterium is part of the normal flora of the human body, residing in areas such as the nose and skin without causing harm in healthy individuals. However, under certain conditions, such as immunocompromised states or when it enters the body through wounds, it can cause a range of infections, including boils, cellulitis, and more serious systemic infections.

The other options do not accurately represent common bacterial infections on the skin. Viruses are not bacteria and cause different types of infections, such as colds or skin rashes, but they are not considered bacterial infections. Fungi can cause skin conditions like athlete's foot or ringworm, but they belong to a different category of pathogens. Protozoa are also not bacteria and typically cause infections of internal organs or systemic issues rather than localized skin infections. Therefore, Staphylococcus aureus stands out as the primary bacteria associated with skin infections.