What is the major cause of nosocomial infections that naturally resides on the skin?

Staphylococcus is a genus of bacteria that naturally resides on the skin and is recognized as a major contributor to nosocomial infections, which are infections acquired in a healthcare setting. One of the most common species, Staphylococcus aureus, can lead to various infections, ranging from minor skin infections to more severe conditions such as pneumonia and sepsis.

This genus is particularly concerning in hospitals because it is capable of forming biofilms on medical devices and can easily transfer from person to person or surface to surface, especially when proper hygiene practices are not followed.

In contrast, while Streptococcus and Enterococcus are also associated with infections, they do not primarily reside on the skin and are less frequently linked to nosocomial infections compared to Staphylococcus. Therefore, Staphylococcus is correctly identified as the major cause among the options provided.