What is a sign of Staphylococcus aureus infection?

A sign of Staphylococcus aureus infection is dermatitis, which refers to inflammation of the skin. This condition can manifest as redness, itching, and swelling, and it often appears in areas where the bacteria may have entered the skin, such as through cuts or abrasions. Staphylococcus aureus can cause a variety of skin infections, ranging from mild to severe, including boils, cellulitis, and impetigo, all of which can lead to dermatitis.

The other options pertain to different conditions or infections that do not specifically indicate a Staphylococcus aureus infection. For example, gelatinous nodules may indicate cysts or other dermatological conditions not necessarily linked to this bacterium, fecal staining typically suggests gastrointestinal issues or parasitic infections, and mild diarrhea could be a symptom of gastrointestinal disturbances that are not specific to Staphylococcus aureus. Therefore, dermatitis is the most relevant and indicative sign of an infection caused by this bacterium.